AOAC RI ERP Final Action Recommendations eBook

Dupont BAX Salmonella Pre- Collaborative Study For Expert Review Panel Use Only Do Not Distribute

A Most Probable Number (MPN) estimation of contamination levels was conducted, using the 1 appropriate reference method, on the day that the analysis of the test samples was initiated. The Least 2 Cost Formulations, Ltd. (LCF) MPN Calculator-Version 1.6 [5] was used to determine the MPN values and 3 95% confidence intervals.

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Table 1. Inoculation Strain Selection

Sample Type

Strain Name

Strain ID

Strain Source

Meat and Seafood

Raw ground beef with soy

DD1467 DD1331 DD1336 DD1332

Unknown Sausage Chicken

S. Typhimurium

Beef trim

S. Berta

Frankfurters

S. Thompson

Shrimp

Shrimp

S. Anatum

Poultry and Eggs

Ground turkey Chicken wings

DD 12913

Turkey

S. Heidelberg Natural Flora S. Braendrup S. Enteritidis

n/a

n/a

Dried eggs Shell eggs

DD1329

Sausage Unknown

ATCC13076

Produce

Frozen peas Orange juice

DD1668 DD4043

Unknown Unknown

S. California

S. Worthington

Dairy Products

Nonfat dry milk

DD1343 DD1333

Environmental

S. Haardt S. Agona

Ice cream

Chicken

Environmentals

Ceramic tile

DD13068 DD13240

Environmental Environmental

S. Lexington S. Mbandaka

Plastic

Miscellaneous

Peanut butter

DD4102 DD 2380 DD13079 DD1469

Nuts

S. St Paul

Cocoa

Unknown

S. Sya

White pepper Infant formula

Basil

S. Newport

Infant formula

S. Ealing

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AOAC INTERNATIONAL

Sample Enrichment 7 Many sample types were evaluated using multiple primary enrichment media to accommodate the 8 validation requirements of multiple countries, which require comparisons to different reference 9 methods (see Table 2). In addition, some sample types were evaluated with an alternative enrichment 10 medium to ensure optimal performance with the test method. All test portions enriched in an 11 alternative medium were subjected to secondary enrichment and confirmation procedures as outlined 12 in the appropriate reference method. Furthermore, in order to best meet the work flow preferences of a 13 wide variety of end users, many sample types were evaluated both before and after a re-growth step 14 (see Table 3). 15