| FDA-BAM |
Seafood, fruits, vegetables, and dairy products |
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(1)
A 25 g of food sample stomached in 225 mL of BLEB and then incubate at 30°C for 4 h
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(2)
After 4 h of incubation, add selective agents such as acriflavine, nalidixic acid, and cycloheximide into enrichment broth, incubate at 30°C for 48 h
-
(3)
Streak enrichment culture onto one of the prescribed selective differential agar plate (Oxford, MOX, or PALCAM) at 24 and 48 h
-
(4)
Incubate agar plate at 35°C for 24–48 h
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(5)
Determine the presumptive colonies and then proceed to confirmation of Listeria sp. and L. monocytogenes
|
<1 CFU/mL |
Hitchins and Jinneman, 2013; Välimaa et al., 2015
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| ISO 11290-1 |
All types of foods |
-
(1)
For primary enrichment, add X g or X mL of food sample to 9X mL of half Fraser broth, incubate at 30°C for 24 ± 2 h
-
(2)
Streak primary enrichment culture onto ALOA and second selective medium (Oxford or PALCAM), incubate at 37°C for 24 ± 2 h. If necessary, further 24 ± 2 h
-
(3)
For secondary enrichment, add 0.1 mL of primary enrichment culture to 10 mL of Fraser broth, incubate at 35 or 37°C for 48 ± 2 h
-
(4)
Streak secondary enrichment culture onto ALOA plate and second selective medium (Oxford or PALCAM), incubate at 37°C for 24 ± 2 h. If necessary, further 24 ± 2 h
-
(5)
Determine the presumptive colonies and then proceed to Confirmation of Listeria sp. and L. monocytogenes
|
<1 CFU/g in 25 g |
ISO, 2004a; Zunabovic et al., 2011; Välimaa et al., 2015
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| USDA-FSIS |
Red meat, poultry products, and egg products |
-
(1)
A 25 g of food sample stomached in 225 mL UVM broth and then incubate at 30 ± 2°C for 20–26 h
-
(2)
Streak primary enrichment culture onto MOX plate and then incubate at 35 ± 2°C for 26 ± 2 h. Determine the presumptive colonies from MOX plate. Proceed to confirmation of Listeria sp. and L. monocytogenes
-
(3)
For secondary enrichment, add 0.1 mL of primary enrichment culture to 10 mL of Fraser broth or MOPS-BLEB
-
(4)
For Fraser broth, incubate at 35 ± 2°C for 26 ± 2 h. After incubation, observe the broth for the presence of L. monocytogenes (darkening of medium due to esculin hydrolysis)
-
(i)
If positive, streak 0.1 mL of the Fraser broth onto MOX plate. Incubate MOX plate at 35 ± 2°C for 26 ± 2 h. Determine the presumptive colonies from MOX plate. Proceed to confirmation of Listeria sp. and L. monocytogenes
-
(ii)
If negative, reincubate Fraser broth for further 24 h. Re-examine the Fraser broth for confirmation of darkening. The sample is considered negative for L. monocytogenes if no darkening of Fraser broth and no suspected colonies on MOX are observed
-
(5)
For MOPS-BLEB, incubate at 35 ± 2°C for 18–24 h
-
(i)
After incubation, streak 0.1 mL of the MOPS-BLEB onto MOX plate. Incubate MOX plate at 35 ± 2°C for 26 ± 2 h
-
(ii)
Determine the presumptive colonies from MOX plate and proceed to confirmation of Listeria sp. and L. monocytogenes
|
<1 CFU/g |
USDA-FSIS, 2013; Välimaa et al., 2015
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