ERP Micro December 2019

Listeriosis can be life‑threatening to certain vulnerable groups, such as pregnant women and those with compromised immune systems and can sometimes be life‑threatening to healthy individuals. Pregnant women and immune‑compromised individuals should take special care when handling samples that are potentially contaminated with Listeria .

D. Sample Enrichment

[Allow the enrichment broths to reach 15–25°C before use. For select matrices, pre-warm LPT broth to 35 ± 1°C prior to use. Frozen samples should be thawed before analysis. Use a blender bag containing filter.] (a) Deli ham, deli turkey, beef hot dogs, breaded chicken nuggets, fresh bagged spinach, fresh bagged lettuce, cooked shrimp, smoked salmon, vanilla ice cream, Mexican soft cheese, pork rillettes, raw milk, salmon offcuts, mixed precooked vegetables, mixed salad and process water (25 g) . ― Add 225 mL LPT broth. Homogenize and incubate at 35 or 37 ± 1°C for 22–26 h. (b) Whole liquid eggs (100 mL) . ― Add 900 mL of pre-warmed LPT broth. Homogenize and incubate at 35 ± 1°C for 22–26 h. (c) Deli ham and smoked salmon (125 g) . ― Add 375 mL of LPT broth. Homogenize and incubate at 35 ± 1°C for 24–28 h. (d) Whey powder (375 g) . ― Add 1125 mL of pre-warmed LPT broth. Homogenize and incubate at 35 ± 1°C for 24–28 h. (e) Environmental samples . ― Add enough LPT broth to cover the sampling device (ex. 10 mL for a swab and 100 mL for a sponge). Homogenize and incubate at 35 or 37 ± 1°C for 22–26 h. Note: For environmental samples, the collection device should first be dampened with a sterile diluent (e.g., LPT broth) containing, if necessary, a suitable neutralizing agent (e.g.

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