AOAC RI ERP Final Action Recommendations eBook

Dupont BAX Salmonella PTM Report Modification Approved 2012 / PTM Certification No. 081201 For Expert Review Panel Use Only Do Not Distribute

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For ground beef enriched according to the reference method, 20 spiked and 5 unspiked samples

were stomached for 2 minutes at 200 rpm with 225 mL buffered peptone water (BPW). Samples were

incubated.at 35 ° C for 20 hours, then aliquots were removed for testing with the BAX® System method.

For reference method testing, 0.5 mL BPW enrichment was added to 10 mL TT-Hajna broth and 0.1

mL BPW enrichment was added to 10 mL RVS broth according to the USDA-MLG method. In addition,

1 mL BPW enrichment was added to 9 mL TBG and 0.1 mL was added to 10 mL RVS broth according

to the HC Compendium method. All secondary enrichments were incubated at 42°C for 22-24 hours.

For ground beef enriched with the alternative BAX® System method, 20 spiked and 5 unspiked

samples were stomached for 2 minutes at 200 rpm with 1.5 L of 46°C TSB + n. Samples were

incubated at 39-42°C for 24 hours, with aliquots removed for testing with the BAX® System method

after 24 hours. For reference method confirmation from the alternative enrichment, 0.5 mL TSB + n

enrichment was added to 10 mL TT-Hajna broth and 0.1 mL BPW enrichment was added to 10 mL

RVS broth according to the USDA-MLG method. In addition, 1 mL BPW enrichment was added to 9

mL TBG and 0.1 mL was added to 10 mL RVS broth according to the HC Compendium method. All

secondary enrichments were incubated at 42°C for 22-24 hours.

For cream cheese enriched according to the reference method, 20 spiked and 5 unspiked samples

were blended with 225 mL lactose broth (LB) and allowed to sit at 25ºC for 55-65 minutes, then the pH

was adjusted to 6.8 ± 0.2, if necessary. Samples were incubated at 35±2°C for 22-26 hours, then

aliquots were removed for testing with the BAX® System method. For reference method testing, 0.1

mL LB enrichment was added to 10 mL FDA RV broth (prepared from constituent components on the

AOAC INTERNATIONAL day of testing) and incubated at 42°C for 22-26 hours. An additional 1 mL LB enrichment was added to 10 mL TT broth and incubated at 35±2°C for 22-26 hours. For cream cheese enriched with the alternative BAX® System method, 20 spiked and 5 unspiked samples were stomached for 2 minutes with pre-warmed (42°C) BAX® System MP media. Samples

were incubated at 39-42°C for 24 hours, with aliquots removed for testing with the BAX® System

method after 12 and 24 hours. For reference method confirmation from the alternative enrichment, 0.1

mL MP enrichment was added to 10 mL FDA RV broth (prepared from constituent components on the