4. AOACRIMicroMethods-2018Awards

982 B ird et al .: J ournal of aoaC i nternational V ol . 99, n o . 4, 2016 time of 96 h. All raw ground beef samples were packed with cold packs to target a temperature of <7°C during shipment. Creamy peanut butter test samples were inoculated 10 days prior to the shipment. Samples were shipped on a Thursday via overnight delivery and held at ambient temperature (20–25°C) until the following Monday when analysis was initiated after a total of 2 weeks of equilibration of the inoculum.

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5% probability level. In addition to POD, repeatability SD (s r ), among-laboratory repeatability SD (s L ), reproducibility SD (s R ), and the homogeneity test of laboratory PODs ( P T ) value were calculated. The s r provides the variance of data within one laboratory, the s L provides the difference in SD between laboratories, and the s R provides the variance in data between different laboratories. The P T indicates if adequate sample homogeneity has occurred between laboratories (14).

In addition to each of the test portions and a separate APC sample, collaborators received a test portion for each matrix labeled as “temperature control.” Participants were instructed to obtain the temperature of this portion upon receipt of the package, document the results on the Sample Receipt Confirmation form provided, and fax or e-mail it back to the study director. The shipment and hold times of the inoculated test material had been verified as a QC measure before study initiation. Collaborators were instructed to follow the appropriate preparation and analysis protocol for eachmatrix for the 3MMDA2 – Salmonella method and the referencemethods. For bothmatrixes, each collaborator received 72 test portions (12 high, 12 low, and 12 uninoculated controls for each method to be performed). For the analysis of the raw ground beef test portions by the 3M MDA 2 – Salmonella method, a 325 g portion was enriched with 975 mL prewarmed (41.5 ± 1°C) ISO BPW, homogenized for 2 min, and incubated for 10 h at 41.5 ± 1°C. For the creamy peanut butter test portions analyzed by the 3MMDA 2 – Salmonella method, a 25 g portion was enriched with 225 mL ISO BPW, homogenized for 2 min, and incubated for 18 h at 37 ± 1°C. After enrichment, samples were assayed by the 3M MDA 2 – Salmonella method and, regardless of presumptive result, confirmed using the appropriate reference method. Both matrixes evaluated by the 3M MDA 2 – Salmonella method were compared to samples analyzed using either the USDA/ FSIS MLG or FDABAM reference method in an unpaired study design. All positive test portions were biochemically confirmed by the API 20E biochemical test (AOAC Official Method 978.24 ; 11) or by the VITEK 2 Gram-negative biochemical identification test (AOAC Official Method 2011.17 ; 12). Polyvalent Salmonella serological testing was also performed. Each collaborating laboratory recorded the results for the reference method and the 3M MDA 2 – Salmonella method on the data sheets provided. The data sheets were submitted to the study director at the end of each week of testing for statistical analysis. Data for each test portion size was analyzed using the probability of detection (POD) statistical model (13). POD was calculated as the number of positive outcomes divided by the total number of trials. The POD was calculated for the candidate presumptive results (POD CP ), the candidate confirmatory results (including false-negative results; POD CC ), the difference in collaborator POD (dLPOD) in the candidate presumptive and confirmatory results (dLPOD CP ), presumptive candidate results that confirmed positive (excluding false-negative results; POD C ), the reference method (POD R ), and the difference in the confirmed candidate and reference methods (dLPOD C ). A dLPOD C confidence interval not containing the value 0 would indicate a statistically significant difference between the 3M MDA 2 – Salmonella and the reference methods at the Test Portion Analysis Statistical Analysis

AOAC Official Method 2016.01 Salmonella spp. in Select Foods and Environmental Surfaces 3M™ Molecular Detection Assay (MDA) 2 – Salmonella Method First Action 2016

(Applicable to detection of Salmonella spp. in raw ground beef (73% lean), raw ground chicken, chicken carcass rinse, chicken carcass sponge, pasteurized liquid whole egg, cooked breaded chicken, instant nonfat dry milk, black pepper, cocoa powder, raw whole shrimp, raw bagged spinach, creamy peanut butter, dry dog food, pasteurized processed American cheese, spent sprout irrigation water, and sealed concrete, stainless steel, and sealed ceramic tile environmental surfaces.) Caution : The 3M MDA 2 – Salmonella is intended for use in

a laboratory environment by professionals trained in laboratory techniques. 3M has not documented the use of this product in industries other than the food and beverage industries. For example, 3M has not documented this product for testing drinking water, pharmaceutical, cosmetics, clinical, or veterinary samples. The 3MMDA 2 – Salmonella has not been evaluated with all possible food products, food processes, testing protocols, or with all possible strains of bacteria.

As with all test methods, the source of enrichment medium can influence the results. The 3MMDA 2 – Salmonella has only been evaluated for use with the enrichment media specified in the manufacturers instructions for use. The 3M MDS instrument is intended for use with samples that have undergone heat treatment during the assay lysis step, which is designed to destroy organisms present in the sample. Samples that have not been properly heat-treated during the assay lysis step may be considered a potential biohazard and should not be inserted into the 3M MDS instrument. The user should read, understand, and follow all safety information in the instructions for the 3MMDS and the 3MMDA 2 – Salmonella . Retain the safety instructions for future reference. Periodically decontaminate laboratory benches and equipment (pipets, cap/decap tools, etc.) with a 1–5% (v/v in water) household bleach solution or DNAremoval solution. When testing is complete, follow current industry standards for the disposal of contaminated waste. Consult the Material Safety Data Sheet for additional information and local regulations for disposal. To reduce the risks associated with exposure to chemicals and biohazards, ( 1 ) perform pathogen testing in a properly equipped laboratory under the control of trained personnel; ( 2 ) always follow standard laboratory safety practices, including wearing appropriate protective apparel and eye protection while handling reagents and contaminated samples; ( 3 ) avoid contact with the contents of the enrichment media and reagent

03/10/2019