Aerobic, mesophilic total bacterial count

Colony count at the incubation temperature of 30°C, 3 days incubation according to FIL/IDF standard method 100B:1991

Coliforms on VRG agar

Colony counting method on violet red bile lactose agar after 24-hour incubation at 30°C according to FIL/IDF Standard 73B:1998

Coliforms in liquid selective medium

MPN method in brilliant green-bile-lactose broth with reading of gas formation after 48 hours of incubation according to FIL/IDF standard method 73A:1985

Enterobacteriaceae on solid selective medium

Colony counting method on solid selective medium violet-red-bile-glucose agar after 24-hour incubation at 30°C according to MOSSEL

Foreign germs on solid selective medium

Colony count of foreign microorganisms in butter, fermented milk and fresh cheese on a sugar-free selective medium after incubation for 48 hours at 30°C according to FIL/IDF Standard Method 153:1991

Psychrotrophic microorganisms

Reference method, colony counting method on standard medium after 10-day incubation at 7°C according to FIL/IDF Standard Method 101A:1991

Psychrotrophic microorganisms

Routine method, colony counting method after 24-hour incubation at 21°C according to FIL/IDF Standard Method 132A:1991

Yeasts on solid selective medium

Colony count method on YGC agar containing chloramphenicol after incubation for 4 days at 25°C according to FIL/IDF Standard Method 94B:1990

Thermoresistant bacterial count

Colony counting procedure according to the standard method for the aerobic total bacterial count after prior heating of the sample material for 35 minutes at 65¼C (laboratory pasteurization)

Proteolytic bacterial count on casein-containing medium

Colony counting method on solid agar medium enriched with caseinate after 2-day incubation at 30°C according to MARTLEY et al [1970]

Lipolytic bacterial count on medium containing butterfat

Colony counting method on solid agar medium enriched with butterfat according to FIL/IDF standard method 41:1966

Acid-forming and non-acid-forming bacteria count

Colony counting method on Chinese lactose agar after 3-day incubation at 30°C with differentiation based on colony color into acid or non-acid formers

Thermophilic spores

Colony counting method on standard medium after 48-hour incubation at 55°C. For the detection of thermophilic spores, the sample material is heated to 100°C for 10 minutes before testing

Anaerobic sulphite-reducing spore formers

MPN method in DRCM medium with incubation for up to 7 days at 37°C under anaerobic conditions in accordance with DIN standard 38 411

Staphylococci - bacterial count on selective media

3-stage method with enrichment in selective broth according to Giolitti and Cantoni, smear on Baird-Parker medium and confirmation of typical colonies by means of coagulase and T-Nase test according to FIL/IDF standard method 60C:1997

Salmonella detection after enrichment

Multi-stage detection with resuscitation, selective enrichment, smear on several selective media and biochemical and serological confirmation according to FIL/IDF standard method 93B:1995 or ISO/FDIS 6785.

Detection of Listeria in 25g (single batch)

Detection according to a four-step cultural method developed by the ISO/TC34/SC9 working group (ISO Standard 11290-1:1996). For information samples, preparation of 25g of a sample (for cheese pooled from 5x5g). Sampling of cheese according to the decision of the BM f. GSuK of 8.5.1996

Escherichia coli - detection by means of Eijkmantest

MPN method using the Eijkman test (gas formation at 44°C and indole formation at 44°C) according to ISO standard method 7251:2001

Bacillus cereus on selective agar medium

Detection of Bacillus cereus by colony count on selective medium PEMBA after 2-day incubation at 30°C according to DIN standard 10 198 (part 1 and 2)

Clostridium perfringens on selective agar

Colony counting method after smearing on selective medium (tryptose-sulphite-cycloserine agar) and anaerobic incubation and subsequent confirmation tests according to ISO standard method 7937-1985. To detect the spores, the sample material is heated to 80°C for 10 minutes before preparation.

charact. Yoghurt spores

Quantitative determination using the colony counting method on M17 agar for the detection of milk streptococci according to FIL/IDF 117B:1997

Lactobacillus acidophilus

Detection on MRS agar and Rogosa SL agar according to the regulations of IDF Bulletin 306, 23-33 (1995)

Bifidobacterium bifidum

Quantitative detection, colony counting method on selective and elective medium. The method is currently under development at FIL/IDF.

Inhibitor test (Galesloot)

Agar diffusion method, application of the sample material using filter plates on agar inoculated with Bac. stearothermophilus, incubation at 62°C according to FIL/IDF standard method 57:1970 (detection sensitivity 0.0025 I.U. penicillin/ml)

Inhibitor test (acidification inhibition)

Detection of acidification inhibition after inoculation of milk with a yoghurt culture according to FRANK

Lipopolysaccharides

Determination of lipopolysaccharides (LPS) of gram-negative bacteria. Microtiter test with Limulus amoebocyte lysate (LAL) according to DIN standard 01.02.1988

Staphylococci - thermonuclease

After chemical extraction of the T-nase, application to toluidine blue DNA agar and observation of pink staining due to DNA cleavage according to FIL/IDF standard method 83:1978

Staphylococcal enterotoxin

Sandwich ELISA test for SET A,B,C,D according to FEY (in the ready-to-use test kit from BOMMELI), detection sensitivity 0.1 ng/ml

Enterococci

Determination of enterococci on kanamycin-esculin agar according to MOSSEL, incubation 24 hours at 37°C

pH value

Potentiometric determination of the pH value

Molds

on solid selective medium, colony counting method on YGC agar containing chloramphenicol after incubation for 4 days at 25°C according to FIL/IDF standard method 94B:1990

Intertest

Acidification inhibition test with Sc. thermophilus in reconstituted milk powder (detection sensitivity 0.02 I.U. Pen./ml). In case of positive results, retest with penicillinase to identify the inhibitor.

Delvo test

Microbiological inhibitor test with test germ Bac. stearothermophilus, ready-to-use test kit from Gist-Brocades, detection sensitivity 0.0025 I.U. penicillin/ml

Listeria (single sample)

Detection of Listeria according to a four-step culture method developed by the ISO/TC34/SC9 working group (ISO Standard 11290-1:1997). A 10g sample is used.

Salmonella detection

Pooled sample after enrichment. Multi-stage detection with resuscitation, selective enrichment, smear on several selective media and biochemical and serological confirmation according to FIL/IDF standard method 93A:1985 (or ISO 6579:1990); preparation of 6 x 250g

Bacillus cereus (qualitative)

Qualitative detection after heating the sample at 80°C, inoculation in litmus milk, incubation for 24h at 30°C, smear on PEMBA medium

Bacillus cereus (quantitative)

After heating the sample for 10 min at 80°C, surface smear on PEMBA medium, incubation for 24h at 30°C, enumeration of typical colonies

aerobic spore count

Colony counting method according to the standard method for total aerobic bacterial count after heating the sample material for 10 minutes at 80°C

Fecal coliforms

Determination of fecal coliforms according to ISO standard method 7251:1984 (FIL/IDF method is in preparation)

Staphylococcus aureus (direct smear)

Smear on Baird-Parker medium and confirmation of typical colonies using coagulase and T-Nase test according to FIL/IDF standard method 145A:1997

Acidification activity

Determination of acidification activity in the recording pH meter (20h at 30°C)

Enterococcus faecium

Determination of Enterococcus faecium on kanamycin-esculin agar according to MOSSEL, incubation 24 hours at 37°C

Lactobacilli (method 1)

Quantitative bacterial count on MRS agar (pH = 5.4), incubation for 48 hours at 37°C. Separate enumeration of different colony types

Bacillus pumilus

Bacterial count on placecount agar, incubation for two days at 37°C

Aromabacteria on elective agar

Colony counting method on WAC or WACCA medium according to Galesloot and Stadhouders, or medium according to NICKELS and LEESMENT

Inhibitor detection (BS-AS test)

Inhibitor detection using the brilliant black AS test with particular sensitivity to sulphonamides (detection sensitivity 0.0025 I.U. penicillin/ml, sulphonamides 0.1-0.3 mg/ml)