The Value of Sound Environmental Practices in Healthcare Facilities Management.

The time has come for healthcare organizations to improve their efforts regarding their impact on the environment, particularly on the communities they serve. For years, healthcare has been at the forefront in addressing social needs with public health initiatives but has lagged on environmental concerns. By carefully reviewing their energy usage and aging infrastructures, healthcare leaders and their facility managers can do a better job of controlling healthcare's environmental impact. Green practices are key indicators of an organization's ethically focused sustainability efforts. So, while healthcare has traditionally focused on its social impact-providing healthcare services is, after all, inherently social-it must expand its community engagement by considering the environmental impact of hospitals and health systems on their communities in the context of climate change.

Validation of Workflow Changes, Phage Concentration and Reformatted Detection Threshold for the Sample6 DETECT/L™ Test: Level 3 Modification.

The AOAC Research Institute Performance Tested MethodsSM Program certified Sample6 DETECT/L™ in April 2014 (Certification No. 041401) for the detection of Listeria species (L. monocytogenes, L. innocua, L. ivanovii, L. seeligeri, L. marthii, L. welshimeri) on stainless steel environmental surfaces. A modification was approved in January 2016, increasing the concentration of sanitizer-neutralizing reagents in detection reagents, increasing the number of phage in the detection solution, and increasing the sample test volume. Moreover, changes to reduce the number of negative controls and add compatibility with polyurethane sponges were also approved. In this modification, to ensure that DETECT/L continues to meet performance expectations, Sample6 evaluated workflow changes to enhance sensitivity and the ease-of-use of the assay. Changes to the phage concentration and detection threshold, plus the inclusion of a confirmation step (DETECT Check), were validated to obtain better accuracy and optimize assay performance. Inclusivity, exclusivity, and robustness testing were conducted by Sample6 to evaluate the changes. A third-party laboratory compared the DETECT/L assay and the U.S. Department of Agriculture reference method in a stainless steel environmental surface matrix study. The data presented in this report demonstrate that the changes proposed to the DETECT/L assay meet or exceed the performance in the current configuration.

Method Modification to Extend the Matrix Claim of the Thermo Scientific RapidFinder Salmonella species, Typhimurium, and Enteritidis Multiplex PCR Kit.

Background: The Thermo Scientific RapidFinder™ Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit is a real-time multiplex PCR assay for the detection and differentiation of Salmonella species, Salmonella Typhimurium, and S. Enteritidis from poultry, pork, and environmental samples. The method has previously been granted certification as Performance Tested Method SM (PTM) 081701, validated according to the AOAC Research Institute (RI) PTM program for poultry (chicken thighs with skin, chicken wings with skin, and chicken nuggets), raw pork sausage matrixes, and stainless steel environmental surface sponges. Objective: This report details the method modification study to validate ground turkey (375 g sample size), chicken carcass rinse, and shell egg matrixes. Methods: The candidate method was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual Chapter 5 for shell eggs and the U.S. Department of Agriculture Food Safety and Inspection Service's Microbiology Laboratory Guidebook 4.09 for ground turkey (375 g) and chicken carcass rinse matrixes. Results: The statistically significant differences found between the candidate and reference methods upon analysis by probability of detection were in favor of the candidate method. Inclusivity and exclusivity testing demonstrated that the RapidFinder Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit was able to detect all the major groups of Salmonella. All exclusivity isolates were correctly excluded. Conclusions: The data presented in this report show that the candidate is suitable for the detection and differentiation of Salmonellae from shell egg, chicken carcass rinse, and ground turkey (375 g) matrixes. Highlights: Thermo Scientific RapidFinder Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit (candidate method) matrix claims extended to include ground turkey (375 g), chicken carcass rinse and shell egg samples.

Evaluation of the Thermo Scientific RapidFinder™ Salmonella Species, Typhimurium, and Enteritidis Multiplex PCR Kit.

The Thermo Scientific RapidFinder™ Salmonella Species, Typhimurium, and Enteritidis Multiplex PCR Kit (candidate method) is a real-time PCR assay for the detection and differentiation of Salmonella spp., and the serovars S. Typhimurium, and S. Enteritidis from poultry, pork, and environmental samples. The method was validated in comparison to the U.S. Department of Agriculture Food Safety and Inspection Service and the U.S. Food and Drug Administration reference methods. Thermo Fisher Scientific (Basingstoke, United Kingdom) tested all matrixes. In addition, two matrixes were analyzed independently by Q Laboratories, Inc. (Cincinnati, OH). Few statistically significant differences were found between the candidate and reference methods when analyzed by probability of detection. When differences were observed, these were in favor of the candidate method. All 200 inclusivity strains and none of the 45 exclusivity strains were detected, which demonstrated that the RapidFinder Salmonella Species, Typhimurium, and Enteritidis Multiplex PCR Kit was able to detect all the major groups of Salmonella, the less common subspecies of S. enterica, and the rarely encountered S. bongori. None of the exclusivity isolates analyzed were detected. Robustness testing demonstrated that the assay gave reliable performance, with specific method deviations outside the recommended parameters. Accelerated stability testing was conducted, validating the assay shelf life.

Evaluation of 3M Molecular Detection Assay (MDA) 2-Listeria for the Detection of Listeria Species in Select Foods and Environmental Surfaces: Collaborative Study, First Action 2016.07.

3M Molecular Detection Assay (MDA) 2-Listeria uses loop-mediated isothermal amplification and bioluminescence detection to rapidly detect Listeria species in a broad range of food types and environmental surfaces. Using an unpaired study design, MDA 2-Listeria was compared with the U.S. Department of Agriculture, Food Safety and Inspection Service's Microbiology Laboratory Guidebook Chapter 8.09 "Isolation and identification of Listeria monocytogenes from red meat, poultry and egg products, and environmental samples" reference method for the detection of Listeria in deli turkey and raw chicken breast fillet. Technicians from 13 laboratories located within the continental United States and Canada participated in the collaborative study. Each matrix was evaluated at three levels of contamination: uninoculated control (0 CFU/test portion), low inoculum (0.2-2 CFU/test portion), and high inoculum (2-5 CFU/test portion). Statistical analysis was conducted according to the probability of detection (POD) statistical model. Results obtained for the low-inoculum-level test portions produced a difference between two laboratory POD values (dLPOD) with 95% confidence intervals of 0.04 (-0.08, 0.17) for deli turkey, indicating the difference between the methods was not statistically significant at the P = 0.05. For raw chicken breast fillet, a dLPOD value with 95% confidence interval of 0.16 (0.04, 0.28) indicated a statistically significant difference between the two methods, with an observed higher proportion of positive results by the candidate method than the reference method.

Evaluation of the 3M™ Molecular Detection Assay (MDA) 2 - Listeria monocytogenes for the Detection of Listeria monocytogenes in a Variety of Foods and Select Environmental Surfaces: Collaborative Study, First Action 2016.08.

The 3M™ Molecular Detection Assay (MDA) 2 - Listeria monocytogenes uses loop-mediated isothermal amplification of unique DNA target sequences combined with bioluminescence to rapidly detect Listeria monocytogenes in a broad range of food types and on environmental surfaces. Using an unpaired study design, technicians from 13 laboratories located in the United States and Canada compared the 3M MDA 2 - Listeria monocytogenes to the U.S. Department of Agriculture Food Safety Inspection Service Microbiology Laboratory Guidebook Chapter 8.09 "Isolation and Identification of Listeria monocytogenes from Red Meat, Poultry, and Egg Products, and Environmental Samples" reference method for the detection of L. monocytogenes in deli turkey and raw chicken breast fillet. Each matrix was evaluated at three levels of contamination: an uninoculated control level (0 CFU/test portion), a low inoculum level (0.2-2 CFU/test portion), and a high inoculum level (2-5 CFU/test portion). Statistical analysis was conducted according to the probability of detection (POD) statistical model. Results obtained for the low inoculum level test portions produced a difference in the collaborating laboratory POD (dLPOD) value of 0.04 with a 95% confidence interval of (-0.08, 0.17) for deli turkey, indicating that the difference between methods was not statistically significant at the 0.05 probability level. For raw chicken breast fillet, a dLPOD value of 0.16 with a 95% confidence interval of (0.04, 0.28) indicated a statistically significant difference, with an observed higher proportion of positive results by the candidate method compared to the reference method.

Validation of the Applied Biosystems RapidFinder Shiga Toxin-Producing E. coli (STEC) Detection Workflow.

The Applied Biosystems™ RapidFinder™ STEC Detection Workflow (Thermo Fisher Scientific) is a complete protocol for the rapid qualitative detection of Escherichia coli (E. coli) O157:H7 and the "Big 6" non-O157 Shiga-like toxin-producing E. coli (STEC) serotypes (defined as serogroups: O26, O45, O103, O111, O121, and O145). The RapidFinder STEC Detection Workflow makes use of either the automated preparation of PCR-ready DNA using the Applied Biosystems PrepSEQ™ Nucleic Acid Extraction Kit in conjunction with the Applied Biosystems MagMAX™ Express 96-well magnetic particle processor or the Applied Biosystems PrepSEQ Rapid Spin kit for manual preparation of PCR-ready DNA. Two separate assays comprise the RapidFinder STEC Detection Workflow, the Applied Biosystems RapidFinder STEC Screening Assay and the Applied Biosystems RapidFinder STEC Confirmation Assay. The RapidFinder STEC Screening Assay includes primers and probes to detect the presence of stx1 (Shiga toxin 1), stx2 (Shiga toxin 2), eae (intimin), and E. coli O157 gene targets. The RapidFinder STEC Confirmation Assay includes primers and probes for the "Big 6" non-O157 STEC and E. coli O157:H7. The use of these two assays in tandem allows a user to detect accurately the presence of the "Big 6" STECs and E. coli O157:H7. The performance of the RapidFinder STEC Detection Workflow was evaluated in a method comparison study, in inclusivity and exclusivity studies, and in a robustness evaluation. The assays were compared to the U.S. Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS) Microbiology Laboratory Guidebook (MLG) 5.09: Detection, Isolation and Identification of Escherichia coli O157:H7 from Meat Products and Carcass and Environmental Sponges for raw ground beef (73% lean) and USDA/FSIS-MLG 5B.05: Detection, Isolation and Identification of Escherichia coli non-O157:H7 from Meat Products and Carcass and Environmental Sponges for raw beef trim. No statistically significant differences were observed between the reference method and the individual or combined kits forming the candidate assay using either of the DNA preparation kits (manual or automated extraction). For the inclusivity and exclusivity evaluation, the RapidFinder STEC Detection Workflow, comprising both RapidFinder STEC screening and confirmation kits, correctly identified all 50 target organism isolates and correctly excluded all 30 nontarget strains for both of the assays evaluated. The results of these studies demonstrate the sensitivity and selectivity of the RapidFinder STEC Detection Workflow for the detection of E. coli O157:H7 and the "Big 6" STEC serotypes in both raw ground beef and beef trim. The robustness testing demonstrated that minor variations in the method parameters did not impact the accuracy of the assay and highlighted the importance of following the correct incubation temperatures.

Evaluation of the 3M™ Petrifilm™ Rapid Aerobic Count Plate for the Enumeration of Aerobic Bacteria: Collaborative Study, First Action 2015.13.

The 3M™ Petrifilm™ Rapid Aerobic Count (RAC) Plate is a sample-ready culture medium system containing dual-sensor indicator technology for the rapid quantification of aerobic bacteria in food products. The 3M Petrifilm RAC Plate was compared to the U.S. Food and Drug Administration Bacteriological Analytical Manual (FDA BAM) Chapter 3 (Aerobic Plate Count) for the enumeration of aerobic bacteria in raw easy-peel shrimp and the Standard Methods for the Examination of Dairy Products (SMEDP) Chapter 6 (Standard Plate Count Method) for the enumeration of aerobic bacteria in pasteurized skim milk and instant nonfat dry milk (instant NFDM). The 3M Petrifilm RAC Plate was evaluated using a paired study design in a multilaboratory collaborative study following current AOAC validation guidelines. Three target contamination levels (low, 10-100 CFU/g; medium, 100-1000 CFU/g; and high 1000-10 000 CFU/g) were evaluated for naturally occurring aerobic microflora for each matrix. For raw easy-peel shrimp, duplicate 3M Petrifilm RAC Plates were enumerated after 24 ± 2 h incubation at both 32 and 35°C. Pasteurized skim milk 3M Petrifilm RAC Plates were enumerated after 24 ± 2 h incubation at 32°C, and instant NFDM 3M Petrifilm RAC Plates were enumerated after 48 ± 3 h incubation at 32°C. No statistical difference was observed between 3M Petrifilm RAC Plate and FDA BAM or SMEDP reference methods for each contamination level.

Evaluation of the 3M™ Molecular Detection Assay (MDA) 2 - Salmonella for the Detection of Salmonella spp. in Select Foods and Environmental Surfaces: Collaborative Study, First Action 2016.01.

The 3M™ Molecular Detection Assay (MDA) 2 - Salmonella uses real-time isothermal technology for the rapid and accurate detection of Salmonella spp. from enriched select food, feed, and food-process environmental samples. The 3M MDA 2 - Salmonella was evaluated in a multilaboratory collaborative study using an unpaired study design. The 3M MDA 2 - Salmonella was compared to the U.S. Food and Drug Administration Bacteriological Analytical Manual Chapter 5 reference method for the detection of Salmonella in creamy peanut butter, and to the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook Chapter 4.08 reference method "Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg and Catfish Products and Carcass and Environmental Samples" for the detection of Salmonella in raw ground beef (73% lean). Technicians from 16 laboratories located within the continental United States participated. Each matrix was evaluated at three levels of contamination: an uninoculated control level (0 CFU/test portion), a low inoculum level (0.2-2 CFU/test portion), and a high inoculum level (2-5 CFU/test portion). Statistical analysis was conducted according to the probability of detection (POD) statistical model. Results obtained for the low inoculum level test portions produced difference in collaborator POD values of 0.03 (95% confidence interval, -0.10 to 0.16) for raw ground beef and 0.06 (95% confidence interval, -0.06 to 0.18) for creamy peanut butter, indicating no statistically significant difference between the candidate and reference methods.

Validation of the RIDASCREEN(®)FAST Milk Kit.

The RIDASCREEN(®)FAST Milk test is a sandwich ELISA for the rapid quantification of milk proteins in various foods. The specific antibodies target casein and ß-lactoglobulin. Samples are extracted and can then be analyzed in less than 40 min. The calibration curve covers a range from 2.5 to 67.5 mg/kg milk protein. The assay was validated with cookies, infant formula, chocolate dessert, ice cream, and sausages. All negative samples were found well below the LOQ of 2.5 mg/kg. Recoveries of the spiked samples were mostly in the range of 80-120%. The LOD of the ELISA was found below 1 mg/kg. The analysis of 39 different substances of interest revealed that no cross-reactivity above the LOQ occurred. Ruggedness testing proved that variations in incubation temperature, reagent volume, incubation time, extraction temperature, and extraction time had no significant influence. The stability at 4-8°C of three independent lots was investigated and found to exceed 18 months. Very good lot-to-lot consistency and no significant loss of the analytical capacity over the shelf life were observed. Incurred cookies and chocolate dessert samples were prepared and analyzed by an independent laboratory; mean recoveries of 94.4 and 102.2% and mean SDs of 10.9 and 6.3%, respectively, were found. For the 0 mg/kg level for both materials, all samples tested returned values of <2.5 mg/kg. Therefore, the analytical performance claims of the manufacturer were confirmed.

Evaluation of the MicroSEQ™ Salmonella spp. Detection Kit with the PrepSEQ™ Rapid Spin Sample Preparation Kit for Detection of Salmonella spp. in Dry Pet Food.

A method modification validation study was conducted to validate the Applied Biosystems MicroSEQ™ Salmonella spp. Detection Kit for the detection of Salmonella spp. in 375 g samples of dried pet food. The MicroSEQ assay protocol, using the Applied Biosystems PrepSEQ™ Rapid Spin DNA Sample Preparation Kit, was compared to the reference method detailed in the U.S Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM; Chapter 5, Salmonella) for detection of Salmonella spp. For each method, 20 replicates were analyzed at a low contamination level of 0.2-2 CFU/test portion, five replicates were analyzed at a high level of contamination of 2-5 CFU/test portion, and five control replicates were also analyzed at 0 CFU/test portion (uninoculated). Statistical analysis was conducted using the Probability of Detection statistical test to determine the ability of the MicroSEQ Salmonella spp. Detection Kit to detect Salmonella from 375 g samples of dried pet food in comparison to the FDA-BAM reference method. The results demonstrated that the MicroSEQ Salmonella spp. Detection Kit was able to accurately detect Salmonella spp. present in dry pet food after an enrichment time of 20 h.

Validation of the Thermo Scientific SureTect Escherichia coli O157:H7 Real-Time PCR Assay for Raw Beef and Produce Matrixes.

The Thermo Scientific™ SureTect™ Escherichia coli O157:H7 Assay is a new real-time PCR assay which has been validated through the AOAC Research Institute (RI) Performance Tested Methods(SM) program for raw beef and produce matrixes. This validation study specifically validated the assay with 375 g 1:4 and 1:5 ratios of raw ground beef and raw beef trim in comparison to the U.S. Department of Agriculture, Food Safety Inspection Service, Microbiology Laboratory Guidebook (USDS-FSIS/MLG) reference method and 25 g bagged spinach and fresh apple juice at a ratio of 1:10, in comparison to the reference method detailed in the International Organization for Standardization 16654:2001 reference method. For raw beef matrixes, the validation of both 1:4 and 1:5 allows user flexibility with the enrichment protocol, although which of these two ratios chosen by the laboratory should be based on specific test requirements. All matrixes were analyzed by Thermo Fisher Scientific, Microbiology Division, Vantaa, Finland, and Q Laboratories Inc, Cincinnati, Ohio, in the method developer study. Two of the matrixes (raw ground beef at both 1:4 and 1:5 ratios) and bagged spinach were additionally analyzed in the AOAC-RI controlled independent laboratory study, which was conducted by Marshfield Food Safety, Marshfield, Wisconsin. Using probability of detection statistical analysis, no significant difference was demonstrated by the SureTect kit in comparison to the USDA FSIS reference method for raw beef matrixes, or with the ISO reference method for matrixes of bagged spinach and apple juice. Inclusivity and exclusivity testing was conducted with 58 E. coli O157:H7 and 54 non-E. coli O157:H7 isolates, respectively, which demonstrated that the SureTect assay was able to detect all isolates of E. coli O157:H7 analyzed. In addition, all but one of the nontarget isolates were correctly interpreted as negative by the SureTect Software. The single isolate giving a positive result was an E. coli O157:NM isolate. Nonmotile isolates of E. coli O157 have been demonstrated to still contain the H7 gene; therefore, this result is not unexpected. Robustness testing was conducted to evaluate the performance of the SureTect assay with specific deviations to the assay protocol, which were outside the recommended parameters and which are open to variation. This study demonstrated that the SureTect assay gave reliable performance. A final study to verify the shelf life of the product, under accelerated conditions was also conducted.

Evaluation of 3M™ Molecular Detection Assay (MDA) Listeria monocytogenes for the Detection of Listeria monocytogenes in Selected Foods and Environmental Surfaces: Collaborative Study, First Action 2014.07.

The 3M™ Molecular Detection Assay (MDA) Listeria monocytogenes combines isothermal amplification and bioluminescence to detect Listeria monocytogenes with high specificity and efficiency in select foods and environmental samples. The 3M MDA Listeria monocytogenes method was evaluated using an unpaired study design in a multilaboratory collaborative study to the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook 8.09 (2011) Isolation and Identification of Listeria monocytogenes from Red Meat, Poultry, and Egg Products and Environmental Samples for deli turkey, and the AOAC Official Method of Analysis(SM) 993.12 Listeria monocytogenes in Milk and Dairy Products for full-fat (4% milk fat) cottage cheese following the current AOAC guidelines. A total of 16 laboratories located in the continental United States and Canada participated in this collaborative study. For deli turkey, 125 g test portions were evaluated using heat-stressed cells by each method. For full-fat cottage cheese, 25 g test portions were evaluated using nonheat-stressed cells. Each matrix had three inoculation levels: an uninoculated control level (0 CFU/test portion), and two levels artificially contaminated with L. monocytogenes, a low inoculum level (0.2-2 CFU/test portion) and a high inoculum level (2-5 CFU/test portion). In total, 1584 unpaired replicate samples were analyzed. Statistical analysis was conducted according to the probability of detection (POD) model. Results obtained for the low inoculum level full-fat cottage cheese test portions produced a difference in cross-laboratory POD (dLPOD) value of -0.08 with a 95% confidence interval (CI) of (-0.20, 0.05). For the low-level deli turkey test portions, a dLPOD value of -0.02 with a 95% CI of (-0.14, 0.11) was obtained.

Evaluation of 3M™ Molecular Detection Assay (MDA) Listeria for the Detection of Listeria species in Selected Foods and Environmental Surfaces: Collaborative Study, First Action 2014.06.

The 3M™ Molecular Detection Assay (MDA) Listeria is used with the 3M Molecular Detection System for the detection of Listeria species in food, food-related, and environmental samples after enrichment. The assay utilizes loop-mediated isothermal amplification to rapidly amplify Listeria target DNA with high specificity and sensitivity, combined with bioluminescence to detect the amplification. The 3M MDA Listeria method was evaluated using an unpaired study design in a multilaboratory collaborative study and compared to the AOAC Official Method of AnalysisSM (OMA) 993.12 Listeria monocytogenes in Milk and Dairy Products reference method for the detection of Listeria species in full-fat (4% milk fat) cottage cheese (25 g test portions). A total of 15 laboratories located in the continental United States and Canada participated. Each matrix had three inoculation levels: an uninoculated control level (0 CFU/test portion), and two levels artificially contaminated with Listeria monocytogenes, a low inoculum level (0.2-2 CFU/test portion) and a high inoculum level (2-5 CFU/test portion) using nonheat-stressed cells. In total, 792 unpaired replicate portions were analyzed. Statistical analysis was conducted according to the probability of detection (POD) model. Results obtained for the low inoculum level test portions produced a difference in cross-laboratory POD value of -0.07 with a 95% confidence interval of (-0.19, 0.06). No statistically significant differences were observed in the number of positive samples detected by the 3M MDA Listeria method versus the AOAC OMA method.

Evaluation of the 3M™ Petrifilm™ Rapid Yeast and Mold Count Plate for the Enumeration of Yeast and Mold in Food: Collaborative Study, First Action 2014.05.

The 3M™ Petrifilm™ Rapid Yeast and Mold (RYM) Count Plate is a simple, ready-to-use chromogenic culture method for the rapid detection and enumeration of yeast and mold in food products. The 3M Petrifilm RYM Count Plate method was compared to the U. S. Food and Drug Administration Bacteriological Analytical Manual (FDA BAM) Chapter 18, Yeasts, Molds and Mycotoxins and the ISO 21527:2008 Microbiology of Food and Animal Feeding Stuffs-Horizontal Method for the Enumeration for Yeast and Molds - Part 1: Colony Count Technique in Products with Water Activity Greater Than 0.95 and Part 2: Colony Count Technique in Products with Water Activity Less Than or Equal to 0.95 reference methods for raw almonds and raw frozen ground beef patties (77% lean). The 3M Petrifilm RYM Count Plate method was evaluated using a paired study design in a multi-laboratory collaborative study following the current AOAC Validation Guidelines. Three target contamination levels (low, 10-100 CFU/g; medium, 100-1000 CFU/g; high 1000-10 000 CFU/g) as well as an uninoculated control level (0 CFU/g) were evaluated for each matrix. Samples evaluated by the 3M Petrifilm RYM Count Plate method were prepared in duplicate and incubated at both 25°C and 28°C. Plates at both temperatures were enumerated after 48 and 60 h of incubation. No significant difference was observed between the 3M Petrifilm RYM Count Plate method and the FDA BAM or ISO 21527 reference methods for each contamination level. No statistical differences were observed between samples analyzed by the 3M Petrifilm RYM Count Plate method (at either 25°C or 28°C) and the reference methods. No statistical significant differences were observed between enumeration of colonies at 48 and 60 h on the 3M Petrifilm RYM Count Plate method and the reference methods.

Detection of Salmonella species in a variety of foods by the DuPont Bax system real-time PCR assay for Salmonella: first action 2013.02.

A multilaboratory study was conducted to evaluate the ability of the DuPont BAX System Real-Time PCR Assay for Salmonella to detect the target species in a variety of foods and environmental surfaces. Internal validation studies were performed by DuPont Nutrition & Health on 24 different sample types to demonstrate the reliability of the test method among a wide variety of sample types. Two of these matrixes-pork and turkey frankfurters and pasteurized, not-from-concentrate orange juice without pulp-were each evaluated in 14 independent laboratories as part of the collaborative study to demonstrate repeatability and reproducibility of the internal laboratory results independent of the end user. Frankfurter samples were evaluated against the U.S. Department of Agriculture, Food Safety and Inspection Service reference method as a paired study, while orange juice samples were evaluated against the U.S. Food and Drug Administration reference method as an unpaired study, using a proprietary media for the test method. Samples tested in this study were artificially inoculated with a Salmonella strain at levels expected to produce low (0.2-2.0 CFU/test portion) or high (5 CFU/test portion) spike levels on the day of analysis. For each matrix, the collaborative study failed to show a statistically significant difference between the candidate method and the reference method using the probability of detection statistical model.

Evaluation of VIDAS UP Listeria assay (LPT) for the detection of Listeria in a variety of foods and environmental surfaces: First Action 2013.10.

The VIDAS UP Listeria (LPT) is an automated rapid screening enzyme phage-ligand based assay for the detection of Listeria species in human food products and environmental samples. The VIDAS LPT method was compared in a multi-laboratory collaborative study to AOAC Official Method 993.12 Listeria monocytogenes in Milk and Dairy Products reference method following current AOAC guidelines. A total of 14 laboratories participated, representing government and industry, throughout the United States. One matrix, queso fresco (soft Mexican cheese), was analyzed using two different test portion sizes, 25 and 125 g. Samples representing each test portion size were artificially contaminated with Listeria species at three levels, an uninoculated control level [0 colony-forming units (CFU)/test portion], a low-inoculum level (0.2-2 CFU/test portion), and a high-inoculum level (2-5 CFU/test portion). For this evaluation, 1800 unpaired replicate test portions were analyzed by either the VIDAS LPT or AOAC 993.12. Each inoculation level was analyzed using the Probability of Detection (POD) statistical model. For the low-level inoculated test portions, difference in collaborator POD (dLPOD) values of 0.01, (-0.10, 0.13), with 95% confidence intervals, were obtained for both 25 and 125 g test portions. The range of the confidence intervals for dLPOD values for both the 25 and 125 g test portions contains the point 0.0 indicating no statistically significant difference in the number of positive samples detected between the VIDAS LPT and the AOAC methods. In addition to Oxford agar, VIDAS LPT test portions were confirmed using Agar Listeria Ottavani and Agosti (ALOA), a proprietary chromogenic agar for the identification and differentiation of L. monocytogenes and Listeria species. No differences were observed between the two selective agars. The VIDAS LPT method, with the optional ALOA agar confirmation method, was adopted as Official First Action status for the detection of Listeria species in a variety of foods and environmental samples.

Evaluation of VIDAS Listeria monocytogenes Xpress (LMX) for the detection of Listeria monocytogenes in a variety of foods: First Action 2013.11.

The VIDAS Listeria monocytogenes Xpress (LMX) is an automated rapid screening enzyme immunoassay for the detection of Listeria monocytogenes in food products. The VIDAS LMX method was compared in a multi-laboratory collaborative study to AOAC Official Method 993.12 Listeria monocytogenes in Milk and Dairy Products reference method following current AOAC guidelines. A total of 14 laboratories participated, representing government and industry, throughout the United States. One matrix, queso fresco (soft Mexican cheese), was analyzed using two different test portion sizes, 25 and 125 g. Samples representing each portion size were artificially contaminated with L. monocytogenes at three levels: an uninoculated control level [0 colony forming units (CFU)/test portion], a low inoculum level (0.2-2 CFU/test portion), and a high inoculum level (2-5 CFU/test portion). For this evaluation, 1800 unpaired replicate test portions were analyzed by either the VIDAS LMX or AOAC 993.12. Each level was analyzed using the Probability of Detection (POD) statistical model. For the low-level inoculated test portions, difference in collaborator POD (dLPOD) values of 0.04, (-0.08, 0.15) and 0.01, (-0.10, 0.13), with 95% confidence intervals, were obtained, respectively, for 25 and 125 g test portions. The range of the confidence intervals for dLPOD values for both the 25 and 125 g test portions contain the point 0.0 indicating no statistically significant difference in the number of positive samples detected between the VIDAS LMX and the AOAC method. In addition to Oxford Agar (OXA), VIDAS LMX test portions were confirmed using Agar Listeria Ottavani and Agosti (ALOA), a proprietary chromogenic agar for the identification and differentiation of L. monocytogenes and Listeria species. No differences were observed between the two selective agars. The VIDAS LMX method, with the optional ALOA agar confirmation method, was adopted as Official First Action status for the detection of L. monocytogenes in a variety of foods.

Evaluation of the 3M™ Petrifilm™ Salmonella express system for the detection of Salmonella species in selected foods: collaborative study.

The 3M™ Petriflm™ Salmonella Express (SALX) System is a simple, ready-to-use chromogenic culture medium system for the rapid qualitative detection and biochemical confirmation of Salmonella spp. in food and food process environmental samples. The 3M Petrifilm SALX System was compared using an unpaired study design in a multilaboratory collaborative study to the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) Microbiology Laboratory Guidebook (MLG) 4.07 (2013) Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg and Catfish Products and Carcass and Environmental Sponges for raw ground beef and the U.S. Food and Drug Administration Bacteriological Analytical Manual (FDA/BAM) Chapter 5, Salmonella (2011) reference method for dry dog food following the current AOAC validation guidelines. For this study, a total of 17 laboratories located throughout the continental United States evaluated 1872 test portions. For the 3M Petrifilm SALX System, raw ground beef was analyzed using 25 g test portions, and dry dog food was analyzed using 375 g test portions. For the reference methods, 25 g test portions of each inatrix were analyzed. The two matrices were artificially contaminated with Salmonella at three inoculation levels: an uninoculated control level (0 CFU/test portion), a low inoculum level (0.2-2 CFU/test portion), and a high inoculum level (2-5 CFU/test portion). Each inoculation level was statistically analyzed using the probability of detection statistical model. For the raw ground beef and dry dog food test portions, no significant differences at the 95% confidence interval were observed in the number of positive samples detected by the 3M Petrifilm SALX System versus either the USDA/FSIS-MLG or FDA/BAM methods.