MICROBIOLOGY TESTING

With a full service microbiology lab, Chestnut Labs offers a wide range of microbiological analysis. From emerging pathogens to invasive spoilage organisms, our microbiologists will work with you to deliver quality data detailed interpretation of your test results. We employ a variety of test methodologies including AOAC, ISO, FDA, USDA, and customer specified methods to assure the microbiological safety and quality of your product. Chestnut Labs will partner with you to provide a value added service with uncompromising quality and a commitment to excellence.

OUR LIST OF SERVICES INCLUDE:

Pathogens

BACILLUS CEREUS

This test allows for a <3, or <10 specification. For the <3 MPN specification, the sample is prepared in dilution water, and pipetted into tubes containing Trypticase Soy-Polymyxin broth resulting into three separate dilutions. After diluting, the sample tubes are incubated, and checked for turbidity. If turbid the dilutions will be carried onto a MYP plate and examined for growth. Likewise, for the <10 specification, the sample is distributed across MYP plates. The plates are then incubated for 48 hrs. and checked for hot pink growth. If colonies are presumptive the colonies are carried on, and confirmed using the Vitek 2 Compact Identification System.

Food poisoning caused by Bacillus cereus may occur when foods are prepared, and held without adequate refrigeration for several hours before serving. Bacillus cereus is an aerobic spore forming bacterium that is commonly found in soil, on vegetables, and in many raw and processed foods. Consumption of foods that contain Bacillus cereus can result in food poisoning. Bacillus cereus food poisoning occurs after the ingestion of foods in which the organism has grown, and formed its toxin(s).

Minimum Sample Size Requirements
25g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
Compendium of Microbiological Methods for the Exam

CAMPYLOBACTER - VIDAS

The VIDAS is an enzyme-linked fluorescent immunoassay. Automated system is used for the detection of Campylobacter antigens using the ELFA technique (Enzyme Linked Fluorescent Assay). The Solid Phase Receptacle (SPR) serves as the solid phase as well as the pipetting device for the assay. The interior of the SPR is coated with anti-Campylobacter antibodies. The reagents for the assay are ready to use, and pre-dispensed in the sealed reagent strips. The sample is placed into the reagent strip by the user. Then the sample is cycled in, and out of the SPR for a specific length of time. The unbound sample components are washed away. Alkaline phosphatade-labeled polylonal antibodies are cycled in, and out of the SPR, and will bind to any Campylobacter antigen captured on the SPR wall. Further wash steps remove unbound conjugate. During the final detection step, the substrate is cycled in, and out of the SPR. The conjugate enzyme catalyzes the hydrolysis of this substrate into a fluorescent product, the fluorescence of which is measured at 450nm. When the assay is completed, the results are analyzed automatically by the instrument, and a test value is generated for each sample. This value is then compared to an internal reference, and each result is interpreted (positive or negative).

Minimum Sample Size Requirements
25g
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
4 days
Method
AOAC

CLOSTRIDIUM PERFRINGENS - DIRECT PLATE COUNT

Sample dilutions are plated onto selective (TSC) agar plates, and overlaid with an additional agar medium. Plates are incubated under anaerobic conditions, and examined for the growth of typical colonies. Presumptive colonies are confirmed and identified by biochemical tests.

Clostridium perfringens is an organism that is responsible for food-borne illness that generally causes mild gastroenteritis. The bacterial cells either sporulate or die, and release enterotoxins that produce the symptoms. The enterotoxins responsible for food-borne illness generally is produced in the intestine although sporulation and enterotoxin production may also occur in foods. Clostridium perfringens is a gram-postivie rod, non-motile, fairly strict anaerobe, spore former. These spores are heat resistant. This organism can replicate very fast (7-8 min/generation) n.producing large amounts of gas creating a stormy fermentation.

Minimum Sample Size Requirements
25g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
FDA-BAM

CRONOBACTER SAKAZAKII - BAX

When Cronobacter sakazakii is present in food or environmental samples, the genetic-based BAX® system uses the polymerase chain reaction (PCR) to rapidly create (amplify) millions of copies of a unique, C. sakazakii -specific DNA fragment through a heating, and cooling process. After this process of amplification, the BAX system begins a detection phase where the fluorescent signal is measured. During this detection, the temperature of the sample is raised to the point where the DNA strands separate, releasing a dye and lowering the signal. The change in fluorescence can be plotted against temperature to generate a melting curve, which is interpreted by the BAX system.

Cronrobacter sakazakii has been reclassified from genus Enterobacter to genus Cronobacter (still within the Enterobacteriaceae family). What was once one species has now been identified as six separate species and three subspecies. Cronobacter sakazakii is a gram-negative, non-spore-forming bacterium. C. sakazakii is a rare, but life-threatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, C. sakazakii kills 40-80 percent of infected newborns diagnosed with this type of severe infection. C. sakazakii meningitis may lead to cerebral abscess or infarction with cyst formation and severe neurologic impairment.

Minimum Sample Size Requirements
25g min
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
DuPont Qualicon BAX

CRONOBACTER SAKAZAKII - ISO 22964

Information on Request

Cronrobacter sakazakii has been reclassified from genus Enterobacter to genus Cronobacter (still within the Enterobacteriaceae family). What was one species has now been identified as six separate species and three subspecies. Cronobacter sakazakii is a gram-negative, non-spore-forming bacterium. C. sakazakii is a rare, but life-threatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, C. sakazakii kills 40-80 percent of infected newborns diagnosed with this type of severe infection. C. sakazakii meningitis may lead to cerebral abscess, or infarction with cyst formation and severe neurologic impairment.

Minimum Sample Size Requirements
300g
Reportable Units
Reported as Present/Absent
Turn Around Time Minimums
4 days
Method
ISO

CRONOBACTER SAKAZAKII - FDA

This method is based on a three-tube enrichment so that the low levels of the microorganism can be detected and quantified. Presumptive identification follows the same procedure as that for identifying other members of the Enterobacteria family. Presumptive identification is declared if the final TSA plating produces yellow colonies. If a presumptive is found, identification follows a series of biochemical analysis.

Cronrobacter sakazakii has been reclassified from genus Enterobacter to genus Cronobacter (still within the Enterobacteriaceae family). What was one species has now been identified as six separate species, and three subspecies. Cronobacter sakazakii is a gram-negative, non-spore-forming bacterium. C. sakazakii is a rare, but life-threatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, C. sakazakii kills 40-80 percent of infected newborns diagnosed with this type of severe infection. C. sakazakii meningitis may lead to cerebral abscess or infarction with cyst formation and severe neurologic impairment.

Minimum Sample Size Requirements
115g in triplicate
Reportable Units
<0.003 CFU/g
Turn Around Time Minimums
3 days
Method
FDA

E.COLI 0157.H- BAX

When E.coli. 0157 is present in food, or environmental samples, the genetic-based BAX® system uses the polymerase chain reaction (PCR) to rapidly create (amplify) millions of copies of a unique, E.coli. 0157 -specific DNA fragment through a heating and cooling process. After this process of amplification, the BAX system begins a detection phase where the fluorescent signal is measured. During this detection the temperature of the sample is raised to the point where the DNA strands separate, releasing a dye, and lowering the signal. The change in fluorescence can be plotted against temperature to generate a melting curve, which is interpreted by the BAX system.

E. coli 0157 is an enterohemorrhagic strain of the bacterium Escherichia coli., and a cause of foodborne illness. Infection often leads to hemorrhagic diarrhea, and occasionally to kidney failure, especially in young children, and elderly. Most illness has been associated with eating undercooked, contaminated ground beef, drinking unpasteurized milk, swimming in or drinking contaminated water, and eating contaminated vegetables.

Minimum Sample Size Requirements
25g min
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
AOAC

LISTERIA - ELISA

The system is composed of specific antibodies to Listeria, including Listeria monocytogenes, that have been adsorbed on the surface of ELISA wells. If Listeria antigens are present in a sample, the antibodies capture them, and all other material is washed away. Next, conjugate specific for Listeria is added, sandwiching the bound Listeria between the two antibodies. The final addition of a substrate results in conversion of the substrate to a darker green color if Listeria was present in the original sample. If no Listeria is present in the original sample, the green color will not be detected.

Listeria is a gram-positive bacterium, motile by means of flagella. The current recognized species of Listeria are L.mono., L. innocua, L. grayi, L. murayi, L. lvanovii, L. welshimen and L. seeligeri. Listeria may also be an indicator of L.mono. Surveys of foods, plants and environments often show non-mono. species as a precursor to L. mono. Some studies suggest that 1-10% of humans may be intestinal carriers of L. monocytogenes. Listeria has been found in at least 37 mammalian species, both domestic and feral, as well as at least 17 species of birds, and possibly some species of fish and shellfish. It can be isolated from soil, silage, and other environmental sources. L. monocytogenes is quite hardy and it resist the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores. Most L. monocytogenes are pathogenic to some degree.

Minimum Sample Size Requirements
25g min
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
AOAC

LISTERIA - VIDAS

The VIDAS Listeria species Xpress is an enzyme-linked fluorescent immunoassay for the use on the VIDAS automated system for the detection of Listeria antigens using the ELFA technique (Enzyme Linked Fluorescent Assay). The Solid Phase Receptacle (SPR) serves as the solid phase as well as the pipetting device for the assay. The interior of the SPR is coated with anti-Listeria antibodies. The reagents for the assay are ready to use, and pre-dispensed in the sealed reagent strips. The sample is placed into the reagent strip by the user. Then the sample is cycled in, and out of the SPR for a specific length of time. The unbound sample components are washed away. Alkaline phosphatase-labeled polylonal antibodies are cycled in, and out of the SPR and will bind to any Listeria antigen captured on the SPR wall. Further wash steps remove unbound conjugate. During the final detection step, the substrate is cycled in and out of the SPR. The conjugate enzyme catalyzes the hydrolysis of this substrate into a fluorescent product, the fluorescence of which is measured at 450nm. When the assay is completed, the results are analyzed automatically by the instrument, and a test value is generated for each sample. This value is then compared to an internal reference and each result is interpreted (positive or negative).

Listeria is a gram-positive bacterium, motile by means of flagella. The current recognized species of Listeria are L.mono., L. innocua, L. grayi, L. murayi, L. lvanovii, L. welshimen and L. seeligeri. Listeria may also be an indicator of L.mono. Surveys of foods, plants and environments often show non-mono. species as a precursor to L. mono. Some studies suggest that 1-10% of humans may be intestinal carriers of L. monocytogenes. Listeria has been found in at least 37 mammalian species, both domestic and feral, as well as at least 17 species of birds, and possibly some species of fish and shellfish. It can be isolated from soil, silage, and other environmental sources. L. monocytogenes is quite hardy and resists the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores. Most L. monocytogenes are pathogenic to some degree.

Minimum Sample Size Requirements
25g
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
AOAC

LISTERIA - PCR- IQ-CHECK

This test is based on gene amplification, and detection by real-time PCR. During the PCR reaction, several cycles of heating and cooling allow DNA denaturation, by heat, followed by primers binding the target region. The DNA polymerase enzyme then uses these primers, and deoxynucleotide triphosphates to extend the DNA, creating copies of the target DNA called amplicons. In real-time PCR, specific oligoncleotide probes are used to detect the DNA during the amplification, by hybridizing to the amplicons. These probes are linked to a fluorophore that fluoresces only when hybridized to the target sequence. In the absence of target DNA, no fluorescence will be detected, and the sample well will be determined negative.

Listeria is a Gram-positive bacterium, motile by means of flagella. The current recognized species of Listeria are L.mono., L. innocua, L. grayi, L. murayi, L. lvanovii, L. welshimen and L. seeligeri. Listeria may also be an indicator of L.mono. Surveys of foods, plants and environments often show non-mono. species as a precursor to L. mono. Some studies suggest that 1-10% of humans may be intestinal carriers of L. monocytogenes. Listeria has been found in at least 37 mammalian species, both domestic and feral, as well as at least 17 species of birds and possibly some species of fish and shellfish. It can be isolated from soil, silage, and other environmental sources. L. monocytogenes is quite hardy and resists the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores. Most L. monocytogenes are pathogenic to some degree.

Minimum Sample Size Requirements
25g
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
AOAC

LISTERIA - BAX

When Listeria is present in food or environmental samples, the genetic-based BAX® system uses the polymerase chain reaction (PCR) to rapidly create (amplify) millions of copies of a unique, Listeria -specific DNA fragments through a heating and cooling process. After this process of amplification, the BAX system begins a detection phase where the fluorescent signal is measured. During this detection the temperature of the sample is raised to the point where the DNA strands separate, releasing a dye, and lowering the signal. The change in fluorescence can be plotted against temperature to generate a melting curve, which is interpreted by the BAX system.

Listeria is a gram-positive bacterium, motile by means of flagella. The current recognized species of Listeria are L.mono, L. innocua, L. grayi, L. murayi, L. lvanovii, L. welshimen and L. seeligeri. Listeria may also be an indicator of L.mono. Surveys of foods, plants and environments often show non-mono. species as a precursor to L. mono. Some studies suggest that 1-10% of humans may be intestinal carriers of L. monocytogenes. Listeria has been found in at least 37 mammalian species, both domestic and feral, as well as at least 17 species of birds and possibly some species of fish and shellfish. It can be isolated from soil, silage, and other environmental sources. L. monocytogenes is quite hardy and resists the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores. Most L. monocytogenes are pathogenic to some degree.

Minimum Sample Size Requirements
25g min
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
30 hrs
Method
AOAC

LISTERIA - USDA

Samples are weighed into pre-enrichment media, and incubated for 22 to 24 hours at 35°C±1°. Subsamples of the pre-enrichment culture are transferred into two selective enrichment broths, which are then incubated at 35°C ± 1°C for approximately 24 hours. Samples are then streaked to selective media. Presumptive growth is confirmed with biochemical assays and serological tests.

Listeria is a gram-positive bacterium, motile by means of flagella. The current recognized species of Listeria are L.mono, L. innocua, L. grayi, L. murayi, L. lvanovii, L. welshimen and L. seeligeri. Listeria may also be an indicator of L.mono. Surveys of foods, plants and environments often show non-mono. species as a precursor to L. mono. Some studies suggest that 1-10% of humans may be intestinal carriers of L. monocytogenes. Listeria has been found in at least 37 mammalian species, both domestic and feral, as well as at least 17 species of birds and possibly some species of fish and shellfish. It can be isolated from soil, silage, and other environmental sources. L. monocytogenes is quite hardy, and resists the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores. Most L. monocytogenes are pathogenic to some degree.

Minimum Sample Size Requirements
25g
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
5 days
Method
USDA

SALMONELLA - ELISA

The system is composed of specific antibodies to Salmonella that have been adsorbed on the surface of ELISA wells. If Salmonella antigens are present in a sample, the antibodies capture the antigens, and all other material is washed away. Next, conjugate specific for Salmonella is added, sandwiching the bound Salmonella between the two antibodies. The final addition of a substrate results in conversion of the substrate to a darker green color if Salmonella was present in the original sample. If no Salmonella was present in the original sample, no green color will be detected.

Salmonella is a rod-shaped, motile bacterium — (nonmotile exceptions are S. gallinarum and S. pullorum) –,nonsporeforming and gram-negative. There is a wide spread occurrence in animals, especially in poultry and swine. Environmental sources of the organism include water, soil, insects, factory surfaces, kitchen surfaces, animal feces, raw meats, raw poultry, and raw seafoods. Salmonellosis is one of the most important food borne illnesses to tract. It differs from most other food borne diseases in that the number of organisms necessary to induce disease may be very low, especially in children, and the infirmed. The FDA has established a zero tolerance for Salmonella in foods.

Minimum Sample Size Requirements
25g min
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
AOAC

SALMONELLA - VIDAS

The VIDAS Salmonella SLM is an enzyme-linked fluorescent immunoassay for the VIDAS automated system enabling the detection of Salmonella antigens using the ELFA technique (Enzyme Linked Fluorescent Assay). The Solid Phase Receptacle (SPR) serves as the solid phase as well as the pipetting device for the assay. The interior of the SPR is coated with anti-Salmonella antibodies. The reagents for the assay are ready to use, and pre-dispensed in the sealed reagent strips. The sample is placed into the reagent strip by the user. Then the sample is cycled in, and out of the SPR for a specific length of time. The unbound sample components are washed away. Alkaline phosphatade-labeled polylonal antibodies are cycled in and out of the SPR and will bind to any Salmonella antigen captured on the SPR wall. Further wash steps remove unbound conjugate. During the final detection step, the substrate is cycled in and out of the SPR. The conjugate enzyme catalyzes the hydrolysis of this substrate into a fluorescent product, the fluorescence of which is measured. When the assay is completed, the results are analyzed automatically by the instrument and a test value is generated for each sample. This value is then compared to an internal reference, and each result is interpreted (positive or negative).

Salmonella is a rod-shaped, motile bacterium — (nonmotile exceptions are S. gallinarum and S. pullorum) –,nonsporeforming and gram-negative. There is a widespread occurrence in animals, especially in poultry and swine. Environmental sources of the organism include water, soil, insects, factory surfaces, kitchen surfaces, animal feces, raw meats, raw poultry, and raw seafoods. Salmonellosis is one of the most important food borne illnesses to tract. It differs from most other food borne diseases in that the number of organisms necessary to induce disease may be very low, especially in children and the infirmed. The FDA has established a zero tolerance for Salmonella in foods.

Minimum Sample Size Requirements
25g
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
AOAC

SALMONELLA - BAX

When Salmonella is present in food or environmental samples, the genetic-based BAX® system uses the polymerase chain reaction (PCR) to rapidly create (amplify) millions of copies of a unique, Salmonella -specific DNA fragment through a heating and cooling process. After this process of amplification, the BAX system begins a detection phase where the fluorescent signal is measured. During this detection the temperature of the sample is raised to the point where the DNA strands separate, releasing a dye, and lowering the signal. The change in fluorescence can be plotted against temperature to generate a melting curve, which is interpreted by the BAX system.

Salmonella is a rod-shaped, motile bacterium — (nonmotile exceptions S. gallinarum and S. pullorum) –,nonsporeforming and gram-negative. There is a wide spread occurrence in animals, especially in poultry and swine. Environmental sources of the organism include water, soil, insects, factory surfaces, kitchen surfaces, animal feces, raw meats, raw poultry, and raw seafoods. Salmonellosis is one of the most important food borne illnesses to tract. It differs from most other food borne diseases in that the number of organisms necessary to induce disease may be very low, especially in children and the infirmed. The FDA has established a zero tolerance for Samonella in foods.

Minimum Sample Size Requirements
25g min
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
1 day
Method
AOAC

SALMONELLA - FDA/BAM

Samples are weighed into pre-enrichment media, and incubated for 22 to 24 hours at 35°C ± 1°C. Subsamples of the pre-enrichment culture are transferred into two selective enrichment broths, which are then incubated at 35°C ± 1°C for approximately 24 hours. Samples are then streaked to selective media. Presumptive growth is confirmed with biochemical assays and serological tests.

Salmonella is a rod-shaped, motile bacterium — (nonmotile exceptions are S. gallinarum and S. pullorum) –,nonsporeforming and gram-negative. There is a widespread occurrence in animals, especially in poultry and swine. Environmental sources of the organism include water, soil, insects, factory surfaces, kitchen surfaces, animal feces, raw meats, raw poultry, and raw seafoods. Salmonellosis is one of the most important food borne illnesses to tract. It differs from most other food borne diseases in that the number of organisms necessary to induce disease may be very low, especially in children and the infirmed. The FDA has established a zero tolerance for Salmonella in foods.

Minimum Sample Size Requirements
25g min
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
5 days
Method
FDA-BAM

SALMONELLA - USDA

Samples are weighed into pre-enrichment media, and incubated for 22 to 24 hours at 35°C ± 1°C. Subsamples of the pre-enrichment culture are transferred into two selective enrichment broths, which are then incubated at 35°C ± 1°C for approximately 24 hours. Samples are then streaked to selective media. Presumptive growth is confirmed with biochemical assays and serological tests.

Salmonella is a rod-shaped, motile bacterium — (nonmotile exceptions are S. gallinarum and S. pullorum) –,nonsporeforming and gram-negative. There is a wide spread occurrence in animals, especially in poultry and swine. Environmental sources of the organism include water, soil, insects, factory surfaces, kitchen surfaces, animal feces, raw meats, raw poultry, and raw seafoods. Salmonellosis is one of the most important food borne illnesses to tract. It differs from most other food borne diseases in that the number of organisms necessary to induce disease may be very low, especially in children and the infirmed. The FDA has established a zero tolerance for Salmonella in foods.

Minimum Sample Size Requirements
25g
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
USDA

SALMONELLA - USP

Samples are weighed into pre-enrichment media and incubated for 22 to 24 hours at 35°C ± 1°C. Subsamples of the pre-enrichment culture are transferred into two selective enrichment broths, which are then incubated at 35°C ± 1°C for approximately 24 hours. Samples are then streaked to selective media. Presumptive growth is confirmed with biochemical assays and serological tests.

Salmonella is a rod-shaped, motile bacterium — (nonmotile exceptions are S. gallinarum and S. pullorum) –,nonsporeforming and gram-negative. There is a wide spread occurrence in animals, especially in poultry and swine. Environmental sources of the organism include water, soil, insects, factory surfaces, kitchen surfaces, animal feces, raw meats, raw poultry, and raw seafoods. Salmonellosis is one of the most important food borne illnesses to tract. It differs from most other food borne diseases in that the number of organisms necessary to induce disease may be very low, especially in children and the infirmed. The FDA has established a zero tolerance for Salmonella in foods.

Minimum Sample Size Requirements
10g/ml
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
3 days
Method
USP<62>

SALMONELLA - SALMONELLA SEROLOGY

The purpose of serotyping is to determine which of the >2300 Salmonella serovars a specific isolate belongs. This is necessary for epidemiological purposes, and for looking for evidence of links between cases. Salmonella has changed over the years and is still evolving. Salmonella serovars belong to two species : S.enterica (six subspecies) and S.bongori (one subspecies). S. bongori contains 18 sevovars, and S. enterica which contains 2300 or more serovars, divided into six subspecies. The subspecies are defined based on the antigenic structure of somatic or cell wall (O) antigens, flagellar (H) antigens, and capsular (Vi) antigens. The antigenic formula gives the O antigen(s) first followed by the H antigen(s). For complete identification of Salmonella requires cultural isolation, biochemical characterization and serotyping.

Minimum Sample Size Requirements
25g
Reportable Units
Reported as Salmonella species
Turn Around Time Minimums
4 days
Method
FDA-BAM

STAPHYLOCOCCUS AUREUS - DIRECT PLATE COUNT

In this procedure the medium is used to asses the “total” or viable coagulase positive Staphylococcus growth of a sample. For products with a < 10 specification the sample would be prepared with a 1:10 dilution. The sample is then suspended onto 3 different Baird- Parker plates. Following the suspension the sample is then incubated for 45-48 hours. Once incubated, the plate will then be counted for presumptive colonies and recorded. The presumptive colonies will then be checked for coagulase activity, for the purpose of determining if the sample contains Staphylococcus aureus.

Staphylococcus aureus is a spherical bacterium (coccus) which on microscopic examination appears in pairs, short chains, or bunched, grape-like clusters. These organisms are gram-positive. S. aureus is highly vulnerable to destruction by heat treatment, and nearly all sanitizing agents. Thus, the presence of this bacterium or its enterotoxins in processed foods, or on food processing equipment is generally an indication of poor sanitation. Foods are examined for the presence of S. aureus and/or its enterotoxins to confirm that S. aureus is the causative agent of food borne illness, to determine whether a food is a potential source of “staph” food poisoning, and to demonstrate post-processing contamination, which is generally due to human contact or contaminated food-contact surfaces.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
FDA-BAM

STAPHYLOCOCCUS AUREUS - Petrifilm

Petrifilm plates contain dry bacterial culture medium and a cold water soluble get. One milliliter of the diluted or undiluted sample is applied to the petrifilm plate. The test suspension is spread out over the surface of the plate by a plastic spreader placed on the overlay film. The water soluble gel is allowed to solidify and the plates are incubated. The resulting colonies are counted and multiplied by the dilution factor to obtain the total microbial count per gram or ml.

Staphylococcus aureus is a spherical bacterium (coccus) which on microscopic examination appears in pairs, short chains, or bunched, grape-like clusters. These organisms are gram-positive. S. aureus is highly vulnerable to destruction by heat treatment and nearly all sanitizing agents. Thus, the presence of this bacterium or its enterotoxins in processed foods, or on food processing equipment is generally an indication of poor sanitation. Foods are examined for the presence of S. aureus and/or its enterotoxins to confirm that S. aureus is the causative agent of food borne illness, to determine whether a food is a potential source of “staph” food poisoning, and to demonstrate post-processing contamination, which is generally due to human contact or contaminated food-contact surfaces.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
1 day
Method
AOAC

STAPHYLOCOCCUS AUREUS - MNP

For the MPN procedure, 11g of the sample is added with 99ml of a diluent. For the <.3 specification, a 1:1 dilution of the sample is prepared in double strength NaCl Trypticase Soy broth with Sodium Pyruvate. In addition, a 1:10 and 1:100 dilution is prepared in single strength NaCl Trypticase Soy broth with Sodium Pyruvate. The dilution series for the <3 specification, a 1:10, 1:100, and 1:1000 dilution is made with single strength NaCl Trypticase Soy broth with Sodium Pyruvate. The dilutions are then incubated for 48 hrs. and examined for turbidity. If turbid, the dilutions are carried on to a separate Baird-Parker agar plate. The plate is then incubated for 48 hours and then examined for Staphylococcus and recorded.

Staphylococcus aureus is a spherical bacterium (coccus) which on microscopic examination appears in pairs, short chains, or bunched, grape-like clusters. These organisms are gram-positive. S. aureus is highly vulnerable to destruction by heat treatment, and nearly all sanitizing agents. Thus, the presence of this bacterium or its enterotoxins in processed foods, or on food processing equipment is generally an indication of poor sanitation. Foods are examined for the presence of S. aureus and/or its enterotoxins to confirm that S. aureus is the causative agent of food borne illness, to determine whether a food is a potential source of “staph” food poisoning, and to demonstrate post-processing contamination, which is generally due to human contact or contaminated food-contact surfaces.

Minimum Sample Size Requirements
15g
Reportable Units
MPN/g
Turn Around Time Minimums
4 days
Method
FDA-BAM

STAPHYLOCOCCUS AUREUS - USP

Samples are weighed into pre-enrichment media, and incubated for 22 to 24 hours at 35°C ± 1°C. Subsamples of the pre-enrichment culture are transferred into two selective enrichment broths, which are then incubated at 35°C ± 1°C for approximately 24 hours. Samples are then streaked to selective media. Presumptive growth is confirmed with biochemical assays and serological tests.

Staphylococcus aureus is a spherical bacterium (coccus) which on microscopic examination appears in pairs, short chains, or bunched, grape-like clusters. These organisms are gram-positive. S. aureus is highly vulnerable to destruction by heat treatment and nearly all sanitizing agents. Thus, the presence of this bacterium or its enterotoxins in processed foods, or on food processing equipment is generally an indication of poor sanitation. Foods are examined for the presence of S. aureus and/or its enterotoxins to confirm that S. aureus is the causative agent of food borne illness, to determine whether a food is a potential source of “staph” food poisoning, and to demonstrate post-processing contamination, which is generally due to human contact or contaminated food-contact surfaces.

Minimum Sample Size Requirements
10g/ml
Reportable Units
Positive or Negative
Turn Around Time Minimums
1 day
Method
USP<62>

STAPHYLOCOCCUS ENTEROTOXIN - VIDAS

The VIDAS is an enzyme-linked fluorescent immunoassay for the VIDAS automated system enabling detection of Staphylococcus Enterotoxin antigens using the ELFA technique (Enzyme Linked Fluorescent Assay). The Solid Phase Receptacle (SPR) serves as the solid phase as well as the pipetting device for the assay. The interior of the SPR is coated with anti-Staphylococcus Enterotoxin antibodies. The reagents for the assay are ready to use, and pre-dispensed in the sealed reagent strips. The sample is placed into the reagent strip by the user. Then the sample is cycled in and out of the SPR for a specific length of time. The unbound sample components are washed away. Alkaline phosphatade-labeled polylonal antibodies are cycled in and out of the SPR and will bind to any Staphylococcus Enterotoxin antigen captured on the SPR wall. Further wash steps remove unbound conjugate. During the final detection step, the substrate is cycled in and out of the SPR. The conjugate enzyme catalyzes the hydrolysis of this substrate into a fluorescent product, the fluorescence of which is measured at 450nm. When the assay is completed, the results are analyzed automatically by the instrument and a test value is generated for each sample. This value is then compared to an internal reference and each result is interpreted (positive or negative).

Food poisoning caused by ingestion of pre-formed, heat-stable enterotoxins produced by certain strains of Staphlococcus aureus is one of the most frequent causes of food poisoning worldwide.

Minimum Sample Size Requirements
25g
Reportable Units
Recorded as Positive or Negative
Turn Around Time Minimums
2 days
Method
AOAC

STREPTOCOCCI

A diluted sample is added to K.F. Streptococcus agar plates, incubated for two days, and the count obtained from the plates are considered a presumptive count.

Streptococci are facultative anaerobic, gram-positive, catalase-negative organisms that often occur as chains or pairs. Streptococci are subdivided into groups by antibodies that recognize surface antigens. These groups may include one or more species. The groups are labeled as A, B, C, D, F, and G. Only groups A and D can be transmitted to humans via food.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
CMMEF

INDICATOR ORGANISMS

Acidophiles

Samples are dispensed in a sterile petri dish using two separate dilutions. MRS agar is poured over the sample, and swirled to mix. Agar is then allowed to harden. Next, the plates are inverted, and incubated at 35° C +1° C for approximately 3 days in a anaerobic environment. The number of acidophiles are enumerated. If presumptive, a catalyses test and a gram stain will be performed.

Acidophiles are organisms that can withstand and even thrive in acidic environments where the pH values range from 1 to 5. Acidophiles include certain types of eukaryotes, bacteria, and archaea that are found in a variety of acidic environments.

Minimum Sample Size Requirements
15g

Reportable Units
CFU/g

Turn Around Time Minimums
3 days

Method
Compendium of Microbiological Methods for the Examination of Foods

AEROBIC PLATE COUNT - Direct Plate Count

Samples may be plated directly, or diluted. A subsample is placed in a sterile petri dish, and plate count agar is poured over the sample. The dish is then swirled to mix, and the agar is allowed to harden. Plates are inverted, and incubated for approximately 48 hours at 35° C ± 1°C (32°C ± 1°C for dairy products). The number of colony-forming units is then counted.

The Aerobic Plate Count (APC) is used as an indicator of the level of bacteria in a food product. The APC does not measure the entire bacterial population, but rather the number of bacteria that grow in the presence of oxygen (aerobically), and at medium range (mesophilic) temperatures.

Minimum Sample Size Requirements
15g

Reportable Units
CFU/g

Turn Around Time Minimums
2 days

Method
AOAC/ CMMEF/ FDA BAM

AEROBIC PLATE COUNT - Petrifilm

Petrifilm plates contain dry bacterial culture medium, and a cold water soluble get. One milliliter of the diluted, or undiluted sample is applied to the petrifilm plate. The test suspension is spread out over the surface of the plate by a plastic spreader placed on the overlay film. The water soluble gel is allowed to solidify, and the plates are incubated. The resulting colonies are counted, and multiplied by the dilution factor to obtain the total microbial count per gram or ml.

The Aerobic Plate Count (APC) is used as an indicator of the level of bacteria in a food product. The APC does not measure the entire bacterial population, but rather the number of bacteria that grow in the presence of oxygen (aerobically) and at medium range (mesophilic) temperatures.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
AOAC

ANAEROBIC PLATE COUNT

Sample dilutions are prepared and pipetted into sterile petri dishes. Plate count agar is then poured and mixed well with sample’s dilutions. The solidified agar plates are covered with thiglycollate agar medium. Plates are incubated under anaerobic conditions, examined for growth, and colonies are counted. Results are reported as colony forming units (CFU) by multiplying the counts with the dilution factor.

The Anaerobic Plate Count is used as an indicator of the level of bacteria in a food product. Anaerobes are defined as organisms that can live in the absence of oxygen. These organisms can contribute to the spoilage of the product.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
AOAC/ CMMEF/ FDA BAM

Bacteria ID - RIBOPRINTER®

Information on Request

This system uses ribosomal RNA to characterize a bacterial sample, and then identifies it by comparing it with reference patterns in the RiboPrinter® Pattern Identification Database.

Minimum Sample Size Requirements
25g
Reportable Units
RiboGroup and Species Identification Reported
Turn Around Time Minimums
4 days
Method
DuPont Qualicon

Bacteria ID - VITEK COMPACT 2 SYSTEM

Information on Request.

The Vitek Compact 2 system uses four separate cards for the identification of gram-negative, gram-positive, aerobic spore-forming bacillus species, yeast and yeast like organisms, anaerobic organisms, and Corynebacterium species.

Minimum Sample Size Requirements
25g
Reportable Units
Species Identification Reported
Turn Around Time Minimums
4 days
Method

COLIFORMS - CHROMOGENIC RAPID E.COLI. 2 PLATE COUNT

The principle of RAPID E.coli. 2 medium relies on simultaneous detection of two enzymatic activities, Beta-D-Glucuronidase (GLUC) and Beta-D Galactosidase (GAL). The medium contains two chromogenic substrates. One substrate is specific to GAL and results in blue green coloration of colonies positive for this enzyme and one substrate is specific to GLUC and results in violet coloration of colonies positive for this enzyme. Coliforms, other than E. coli., (GAL+/GLUC-) form blue to green colonies while, specifically, E. coli. (GAL+/GLUC+) form violet colonies. A count of total coliforms can be obtained by adding the number of blue colonies and the number of violet colonies. Differentiation of coliforms and specifically E. coli. is carried out by observing a simple color change reaction.

Coliform is not a taxonomic classification, but rather a working definition used to describe a group of gram-negative, facultative anaerobic rod-shaped bacteria that ferment lactose to produce acid, and gas within 48 hrs. at 35°C. The coliform group consists of 7 genera: Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Serratia, and Yersinia. Their presence in food is generally regarded as an indicator of post process, and/or fecal contamination; thus the name “indicator organisms” is commonly applied to this group. The enumeration of coliforms is among the most commonly employed methods for assessing microbiological quality of foods.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
1 day
Method
AOAC

COLIFORMS - MPN

The bacteriological examination of food samples for the presence of coliform bacteria involves a three-step procedure. Each step depends on the type of sample being examined, and the information desired. The presumptive test involves inoculating fermentation tubes of lauryl sulfate tryptose (LST) broth with decimal multiples, and fractions of the sample under test. Three to five tubes are used for each fraction. The tubes are incubated for 48 ± 2 hours at 35°C ± 1°C, after which they are examined for turbidity and gas production. The absence of gas after 48 ± 2 hours constitutes a negative test. To confirm, all tubes showing gas production within 48 ± 2 hours are used to inoculate confirmatory fermentation tubes of brilliant green lactose bile (BGLB). The tubes of BGLB broth are incubated at 35°C ± 1° for 48 ± 2 hours. The formation of gas in any amount constitutes a positive confirmed test. From the reference of confirmed positive tubes at each dilution, the MPN is derived from the MPN tables.

Coliform is not a taxonomic classification, but rather a working definition used to describe a group of gram-negative, facultative anaerobic rod-shaped bacteria that ferment lactose to produce acid, and gas within 48 hrs. at 35°C. The coliform group consists of 7 genera: Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Serratia, and Yersinia. Their presence in food is generally regarded as an indicator of post process and/or fecal contamination; thus the name “indicator organisms” is commonly applied to this group. The enumeration of coliforms is among the most commonly employed methods for assessing microbiological quality of foods.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
FDA-BAM

COLIFORMS - PETRIFILM

Petrifilm plates contain dry culture medium and a cold water soluble gel. One milliliter of the diluted or undiluted sample is applied to the petrifilm plate. The test suspension is spread out over the surface of the plate by a plastic spreader placed on the overlay film. The water soluble gel is allowed to solidify and the plates are incubated. Typical colonies of coliforms are counted and multiplied by the dilution factor to obtain the total count for each per gram or ml.

Coliform is not a taxonomic classification, but rather a working definition used to describe a group of Gram-negative, facultative anaerobic rod-shaped bacteria that ferments lactose to produce acid and gas within 48 hrs. at 35°C. The coliform group consists of 7 genera: Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Serratia, and Yersinia. Their presence in foods is generally regarded as an indicator of post process and/or fecal contamination; thus the name “indicator organisms” is commonly applied to this group. The enumeration of coliforms is among the most commonly employed methods for assessing microbiological quality of foods.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
1 day
Method
AOAC

COLIFORMS - VRB Plate Count

Violet Red Bile (VRB) agar is a standard method selective plating medium used for the presumptive phase of enumerating coliform bacteria in foods and dairy products. Those organisms of the coliform group are able to ferment lactose, and form purplish red colonies, 1-2 mm in diameter, generally surrounded by a reddish zone of precipitated bile.

Coliform is not a taxonomic classification, but rather a working definition used to describe a group of gram-negative, facultative anaerobic rod-shaped bacteria that ferment lactose to produce acid and gas within 48 hrs. at 35°C. The coliform group consists of 7 genera: Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Serratia, and Yersinia. Their presence in food is generally regarded as an indicator of post process, and/or fecal contamination; thus the name “indicator organisms” is commonly applied to this group. The enumeration of coliforms is among the most commonly employed methods for assessing microbiological quality of foods.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
1 day
Method
FDA-BAM

E.COLI - CHROMOGENIC RAPID E.COLI 2 PLATE COUNT

The principle of RAPID E.coli. 2 medium relies on simultaneous detection of two enzymatic activities, Beta-D-Glucuronidase (GLUC) and Beta-D Galactosidase (GAL). The medium contains two chromogenic substrates. One substrate is specific to GAL, and results in blue green coloration of colonies positive for this enzyme, and one substrate is specific to GLUC and results in violet coloration of colonies positive for this enzyme. Coliforms, other than E. coli., (GAL+/GLUC-) form blue to green colonies while, specifically, E. coli. (GAL+/GLUC+) form violet colonies. A count of total coliforms can be obtained by adding the number of blue colonies, and the number of violet colonies. Differentiation of coliforms and E. coli. is carried out by observing a simple color change reaction.

E. coli. is widely distributed in the intestine of humans, and warm-blooded animals. E.coli. is the predominant facultative anaerobe in the bowel, and part of the essential intestinal flora that maintains the physiology of the healthy host. E. coli. is a member of the family Enterobacteriaceae , which includes many genera, including known pathogens such as Salmonella, Shigella, and Yersinia. Although most strains of E. coli. are not regarded as pathogens, they can be opportunistic pathogens that cause infections in immunocompromised hosts.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
1 day
Method
AOAC

E.COLI - MPN

The bacteriological examination of food samples for the presence of coliform bacteria involves a three-step procedure. Each step depends on the type of sample being examined, and the information desired. The presumptive test involves inoculating fermentation tubes of lauryl sulfate tryptose (LST) broth with decimal multiples, and fractions of the sample under test. Three to five tubes are used for each fraction. The tubes are incubated for 48 ± 2 hours at 35°C ± 1°C, after which they are examined for turbidity and gas production. The absence of gas after 48 ± 2 hours constitutes a negative test. All tubes showing gas production within 48 ± 2 hours are used to inoculate confirmatory fermentation tubes of EC broth. The tubes of EC broth are incubated in a 45.5°C ± 0.2°C water bath for 48 ± 2 hours. The formation of gas in any amount constitutes a positive confirmed fecal coliform test. For E. coli. confirmation growth is confirmed bio-chemically. From the reference of confirmed positive tubes at each dilution, the MPN is derived from the MPN tables.

E. coli. is widely distributed in the intestine of humans and warm-blooded animals, and is the predominant facultative anaerobe in the bowel and part of the essential intestinal flora that maintains the physiology of the healthy host. E. coli. is a member of the family Enterobacteriaceae , which includes many genera, including known pathogens such as Salmonella, Shigella, and Yersinia. Although most strains of E. coli. are not regarded as pathogens, they can be opportunistic pathogens that cause infections in immunocompromised hosts.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
FDA-BAM

E.COLI - USP

Sample is diluted and inoculated into a selective broth, and incubated at 33°C ± 2°C for 14 to 18 hrs. The sample is then transferred into MacConkey broth, and subcultured out onto MacConkey agar for 33°C + 2°C for 18 to 72 hrs.

E. coli. is widely distributed in the intestine of humans and warm-blooded animals. E.coli. is the predominant facultative anaerobe in the bowel, and part of the essential intestinal flora that maintains the physiology of the healthy host. E. coli. is a member of the family Enterobacteriaceae , which includes many genera, including known pathogens such as Salmonella, Shigella, and Yersinia. Although most strains of E. coli. are not regarded as pathogens, they can be opportunistic pathogens that cause infections in immunocompromised hosts.

Minimum Sample Size Requirements
20g
Reportable Units
Positive or Negative
Turn Around Time Minimums
3 days
Method
USP<62>

E.COLI - PETRIFILM

Petrifilm plates contain dry culture medium and a cold water soluble gel. One milliliter of the diluted or undiluted sample is applied to the petrifilm plate. The test suspension is spread out over the surface of the plate by a plastic spreader placed on the overlay film. The water soluble gel is allowed to solidify, and the plates are incubated. Typical colonies of coliforms or Escherichia coli are counted, and multiplied by the dilution factor to obtain the total count for each per gram or mL.

E. coli. is widely distributed in the intestine of humans, and warm-blooded animals. E.coli. is the predominant facultative anaerobe in the bowel and part of the essential intestinal flora that maintains the physiology of the healthy host. E. coli. is a member of the family Enterobacteriaceae , which includes many genera, including known pathogens such as Salmonella, Shigella, and Yersinia. Although most strains of E. coli. are not regarded as pathogens, they can be opportunistic pathogens that cause infections in immunocompromised hosts.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
AOAC

ENTEROBACTERIACEAE - VRBG PLATE COUNT

A dilution of the sample is prepared, and plated with VRBG agar. Typical colonies (purple with halos) are picked and confirmed bio-chemically.

Enterobacteriaceae is a family of gram-negative bacilli that contains more than 100 species of bacteria that normally inhabit the intestines of humans and animals. Members of the Enterobacteriaceae are relatively small, non-spore forming bacilli. Some are motile, while others are not. Enterobacteriaceae is often used in food microbiology as an indicator organism. Their presence in the processed food may indicate inadequate treatment or post process contamination from the environment.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
1 day
Method
CMMEF

ENTEROBACTERIACEAE - PETRIFILM

Petrifilm plates contain dry culture medium, and a cold water soluble gel. One milliliter of the diluted or undiluted sample is applied to the petrifilm plate. The test suspension is spread out over the surface of the plate by a plastic spreader placed on the overlay film. The water soluble gel is allowed to solidify, and the plates are incubated. Typical colonies of are counted and multiplied by the dilution factor to obtain the total count for each per gram or mL.

Enterobacteriaceae is a family of gram-negative bacilli that contains more than 100 species of bacteria that normally inhabit the intestine of humans and animals. Members of the Enterobacteriaceae are relatively small, non-spore forming bacilli. Some are motile, while others are not. Enterobacteriaceae is often used in food microbiology as an indicator organism. Their presence in the processed food may indicate inadequate treatment or post process contamination from the environment.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
1 day
Method
AOAC

FECAL COLIFORMS - MPN

The bacteriological examination of food samples for the presence of coliform bacteria involves a three-step procedure. Each step depends on the type of sample being examined and the information desired. The presumptive test involves inoculating fermentation tubes of lauryl sulfate tryptose (LST) broth with decimal multiples and fractions of the sample under test. Three to five tubes are used for each fraction. The tubes are incubated for 48 ± 2 hours at 35°C ± 1°C, after which they are examined for turbidity and gas production. The absence of gas after 48 ± 2 hours constitutes a negative test. All tubes showing gas production within 48 ± 2 hours are used to inoculate confirmatory fermentation tubes of EC broth, 2% broth using a flamed bacteriological loop or sterile disposable loop. The tubes of EC broth are incubated in a 45.5°C ± 0.2°C water bath for 48 ± 2 hours. The formation of gas in any amount constitutes a positive confirmed fecal coliform test. From the reference of confirmed positive tubes at each dilution, the MPN is derived from the MPN tables.

Coliform is not a taxonomic classification, but rather a working definition used to describe a group of gram-negative, facultative anaerobic rod-shaped bacteria that ferment lactose to produce acid and gas within 48 hrs. at 35°C. The coliform group consists of 7 genera: Citrobacter, Enterobacter, Escherichia, Hafnia, Klebsiella, Serratia, and Yersinia. Their presence in food is generally regarded as an indicator of post process and/or fecal contamination; thus the name “indicator organisms” is commonly applied to this group. The enumeration of coliforms is among the most commonly employed methods for assessing microbiological quality of foods.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
FDA-BAM

FECAL STREPTOCOCCI

The sample is plated to Bile Esculin agar and incubated for 24 hrs.

Fecal Streptococci are gram-postive bacteria belonging to the genus Streptococcus, and include the following speci: faecalis, faecium, avium, casseliflavus, gallinarum, durans, hirae, malodoratus, and mundtii. The source of these organisms is varied and includes the mouth and intestinal contents of warm-blooded animals, raw milk, insects, and plant material. Fecal Strep. is commonly found at low numbers in nonsterile foods where their presence often is not related to fecal contamination. A number of fecal streptococci can survive a wide variety of temperatures.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
CMMEF

LACTIC ACID BACTERIA - TOTAL LAB

The samples are dispensed in a sterile petri dish using two separate dilutions. MRS agar is poured over the sample, and swirled to mix. Agar is allowed to harden. Plates are inverted and incubated at 35°C +1°C for approximately 3 days in a anaerobic environment.

Lactic acid bacteria are a group of related bacteria that produce lactic acid as a result of carbohydrate fermentation. These microbes are broadly used by us in the production of fermented food products, such as yogurt, cheeses, sauerkraut, and sausage. Lactic acid bacteria are used in the food industry for several reasons. Their growth lowers both the carbohydrate content of the foods that they ferment, and the pH due to lactic acid production. It is this acidification process which is one of the most desirable side-effects of their growth. The pH may drop to as low as 4.0, low enough to inhibit the growth of most other microorganisms including the most common human pathogens, thus allowing these foods prolonged shelf life.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
3 days
Method
CMMEF

LACTIC ACID BACTERIA - HETEROFERMENTATIVE LACTOBACILLUS

This procedure uses MPN tubes containing MRS Broth. The tubes are incubated for 4 days at 35°C + 1°C and examined for gas production and turbidity indicating the possible presence of Heterofermentative Lactobacilli. The MRS broth is then examined microscopically to exclude yeast, and confirm the presence of gram-positive bacilli.

Lactic acid bacteria are a group of related bacteria that produce lactic acid as a result of carbohydrate fermentation. These microbes are broadly used in the production of fermented food products, such as yogurt, cheeses, sauerkraut, and sausage. Lactic acid bacteria are used in the food industry for several reasons. Their growth lowers both the carbohydrate content of the foods that they ferment, and the pH due to lactic acid production. It is this acidification process which is one of the most desirable side-effects of their growth. The pH may drop to as low as 4.0, low enough to inhibit the growth of most other microorganisms including the most common human pathogens, thus allowing these foods prolonged shelf life.

Minimum Sample Size Requirements
15g
Reportable Units
MPN/g
Turn Around Time Minimums
4 days
Method
CMMEF

PROTEOLYTIC COUNT

Proteolytic bacteria are protease-producing microorganisms that break down protein in food and result in foul odors. Proteolytic enzymes produced by psychrotrophic bacteria during growth in milk often remain active after HTST and UHT heat treaments, and they reduce the quality of stored heat-treated products. Tests for proteolytic bacteria may be useful in identifying practices during handling, and storage of raw or processed milk that can cause contamination of products.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
SMEDP

PSEUDOMONAS

Samples are weighed and dispensed into two dilutions of two different selective agars, and incubated for 18 to 24 hours at 35°C ± 2°C. Samples are then examined and counted. Presumptive growth is confirmed with biochemical assays and serological tests.

Pseudomonas is a gram-negative, aerobic rod belonging to the bacterial family Pseudomonadaceae. Like other members of the genus, Pseudomonas aeruginosa is a free-living bacterium, commonly found in soil and water. Pseudomonas aeruginosa is an opportunistic pathogen, meaning that it exploits some break in the host defenses to initiate an infection.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
CMMEF

PSYCHROTROPHIC PLATE COUNT

Samples are diluted, and a subsample is placed in a sterile petri dish. Standard Methods agar is poured over the sample and swirled to mix. Agar is allowed to harden. Plates are inverted and incubated at 7°C +1°C for approximately 10 days. The Bacteria is identified and the colonies are counted.

Psychrotrophs are microorganisms that grow in food at refrigeration temperatures. They can produce visible growth at 7°C ± 1° C within 7-10 days, regardless of their optimal growth temperature. Psychrotrophs include bacteria, yeast, and molds. The bacteria include rods, cocci, and vibrios; spore formers and non-sporeformers; gram-negative and gram-positive bacteria, and aerobes, facultative anaerobes, and anaerobes.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
7 days
Method
SMEDP

SPORES - THERMOPHILLIC AEROBIC

Spore forming bacteria are of special concern to those involved in food processing. Spores and bacteria are present almost everywhere in the environment, and food processing facilities are no exception. When sporeforming bacteria encounter nutrient deprivation, and dense population conditions, they undergo a developmental process called sporulation, which results in the production of resistant, metabolically inactive spores. The spores are highly resistant to environmental stresses such as high temperatures, acids, and disinfectants. Normal pasteurization will kill pathogens, and most vegetative cells; however, it will not destroy bacterial spores. The spores may then reside dormant in the product or if conditions are met, such as when milk powder is reconstituted, they can germinate, and through enzymatic activity cause spoilage of the product.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/10g
Turn Around Time Minimums
2 days
Method
CMMEF

SPORES - THERMOPHILLIC ANAEROBIC

Spore forming bacteria are of special concern to those involved in food processing. The non-hydrogen sulfide producing thermophilic anaerobic sporeformers are classified in the family Bacillaceae, genus Clostridium. The organisms produce acid and an abudance of gas from glucose, lactose, sucrose, salicin, and starch. Neither toxins nor infections are produced; therefore, the organisms are of spoilage, but not of public health significance. The most notable characteristic of these organisms is the heat resistance exhibited by the spores. Therefore, their survival in canned foods is not unexpected, but thermophilic anaerobes are rarely found in foods processed above 121° C.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/10g
Turn Around Time Minimums
2 days
Method
CMMEF

SPORES - MESOPHILLIC AEROBIC

The mesophilic spore-formers include most of the common spoilage and disease organisms. In this procedure the sample is heated, and subcultured into Standard Methods agar. Then the sample is incubated, and the bacterial colonies are counted and the spore count calculated.

Mesophilic spore forming bacteria are moderate temperature loving microbes that have an optimum growth temperature of 25°C to 40°C. The mesophilic spore formers include most of the common spoilage and disease organisms.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
CMMEF

SPORES - IRON SULFITE

Applicable for the enumeration of Iron Sulfite spores.

Sulfide spoilage is relatively rare; although, it may occur in canned sweet corn, peas, mushroom products, infant formulas, and other non-acid foods. Most isolates from sulfide spoilage achieve optimum growth at 55°C. It is also non-existent in acid foods because of the pH requirements for the growth to occur. Products that suffer from this spoilage possess a strong odor of hydrogen sulfide; however, exhibit no other putrefactive odor. The cause of sulfide spoilage is a combination of high spore counts, the heat resistance of the spores, and the holding of finished product at elevated temperatures.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
7 days
Method
CMMEF

Thermophiles

This procedure uses Standard Methods agar incubated at 55°C + 1°C for 48 hrs.

Thermophilic organisms may or may not be destroyed by the thermal process. When present,these organisms are able to rapidly increase in numbers in milk or dairy products held at temperatures in the thermophilic growth range (40°C to 90°C with an optimal range of 55°C to 65°C)for long periods of time. Acceptable levels for thermophilic bacteria vary according to sample type, stage of processing, and future usage.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
2 days
Method
SMEDP

Yeast and Mold - OSMOPHILIC YEAST

Samples are diluted and subsamples are placed in sterile petri dishes. MY40G agar is poured over the sample and swirled to mix. Agar is allowed to harden. Plates are inverted and incubated at 30° C + 1°C for approximately 5 days. The number of yeast and mold colonies are counted.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or home cooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
5 days
Method
CMMEF

YEAST AND MOLD - PLATE COUNT, PDA

The samples are diluted and a subsample is placed in a sterile petri dish. Potato Dextrose agar is poured over the sample and swirled to mix. Agar is allowed to harden. Plates are inverted and incubated at 22°C to 25°C for approximately 5 days. The number of mold and yeast colonies are counted.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or home cooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
5 days
Method
CMMEF

YEAST AND MOLD - PLATE COUNT, CRB

The samples are diluted and a subsample is placed in a sterile petri dish. Cooke Rose Bengal agar is poured over the sample, and swirled to mix. Agar is allowed to harden. Plates are inverted and incubated at 22° C to 25° C for approximately 5 days. The number of mold and yeast colonies are counted.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or home cooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
4 days
Method
CMMEF

YEAST AND MOLD - PLATE COUNT, DRCB

Typically PDA agar is used in the detection of yeast and mold. Plates are incubated for a specified time concerning the agar, normally no longer than 5 days. Other common agars used are CRB (Cooke Rose Bengal), or DRBC (Dichloran Rose Bengal Chloramphenicol) coupled with an antibiotic to prevent bacterial growth.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or home cooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
5 days
Method
CMMEF

YEAST AND MOLD - PRESERVATIVE RESISTANT YEAST

The samples are diluted and subsamples are placed in sterile petri dishes. Standard Methods agar is poured over the sample and swirled to mix. Agar is allowed to harden. Plates are inverted and incubated at 25°C +1°C for approximately 5 days. The number of yeast colonies are counted.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or home cooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
5 days
Method
CMMEF

YEAST AND MOLD - SIMPLATE-(COMBINED COUNT)

Simplate for yeast and mold indicator method is used for the detection, and quantification of yeast and mold in foods. It is based on binary detection technology which equates the presence of yeast and mold to the presence of a color change in the medium. The medium is inoculated with a prepared sample, dispensed into a Simplate device and incubated for a minimum of 56 hours. The medium changes color in the presence of yeast and/or mold.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or home cooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
3 days
Method
AOAC

YEAST AND MOLD - USP

Sample is diluted into a 1:10 dilution, and pipetted onto two separate petri dishes. Next, 15 to 20 ml of a selective agar is poured over the sample. Finally, the dishes are inverted and incubated at 23°C + 2°C for 5 to 7 days.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or homecooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
10g/ml
Reportable Units
CFU/g
Turn Around Time Minimums
5 days
Method
USP<61>

YEAST AND MOLD - PETRIFILM

Petrifilm plates contain dry culture medium, and a cold water soluble gel. One milliliter of the diluted or undiluted sample is applied to the petrifilm plate. The test suspension is spread out over the surface of the plate by a plastic spreader placed on the overlay film. The water soluble gel is allowed to solidify, and the plates are incubated. Typical colonies of coliforms or Escherichia coli are counted and multiplied by the dilution factor to obtain the total count for each per gram or ml.

The large and diverse group of microscopic foodborne yeasts and molds (fungi) includes several hundred species. The ability of these organisms to attack many foods is due in large part to their relatively versatile environmental requirements. Although the majority of yeasts and molds are obligate aerobes (require free oxygen for growth), their acid/alkaline requirement for growth is quite broad, ranging from pH 2 to above pH 9. Their temperature range (10-35°C) is also broad, with a few species capable of growth below or above this range. Moisture requirements of foodborne molds are relatively low; most species can grow at a water activity (aw) of 0.85 or less, although yeasts generally require a higher water activity. Both yeasts and molds cause various degrees of deterioration and decomposition of foods. They can invade and grow on virtually any type of food at any time. They invade crops such as grains, nuts, beans, and fruits in fields before harvesting and during storage. They also grow on processed foods and food mixtures. Several foodborne molds, and possibly yeasts, may also be hazardous to human or animal health because of their ability to produce toxic metabolites known as mycotoxins. Most mycotoxins are stable compounds that are not destroyed during food processing or homecooking. Even though the generating organisms may not survive food preparation, the preformed toxin may still be present.

Minimum Sample Size Requirements
15g
Reportable Units
CFU/g
Turn Around Time Minimums
3 days
Method
AOAC

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