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San Antonio, TX, United States

Brandt A.L.,Food Safety Net Services Ltd.
American Laboratory | Year: 2015

Foods, beverages and dietary supplements are considered adulterated if they are unwholesome, impure, unsafe or otherwise unfit for consumption. However, regulatory agencies around the world have established specific criteria to define adulterated products, and these vary from one country to another. These criteria are constantly evolving as new ingredient sources are utilized, new processing technologies are implemented and new contaminants are discovered. Laboratories must continue to develop methods that detect intentional adulteration. Likewise, method development must also encompass unintentional adulterants such as incidental microbiological contamination of food products. Liquid chromatography with triple quadrupole tandem mass spectrometry (LC-MS/MS) is still one of the benchmarks for testing melamine and related compounds in the laboratory. Innovative methods such as fluorescence resonance energy transfer (FRET), surface-enhanced Raman spectroscopy (SERS), and ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC/HR-MS) can also be used. The advent of real-time polymerase chain reaction (PCR)-based technologies allowed methods to be developed to detect the presence of microbiological adulterants more rapidly and with often greater sensitivity than cultural method. There has also been significant movement toward non-PCR-based technologies for the detection of food-borne pathogens. One such method that has been harnessed for assay development is loop-mediated isothermal amplification. Source


Sharma N.,InstantLabs Medical Diagnostics Corporation | Bambusch L.,InstantLabs Medical Diagnostics Corporation | Le T.,InstantLabs Medical Diagnostics Corporation | Morey A.,Food Safety Net Services Ltd. | And 3 more authors.
Journal of AOAC International | Year: 2014

The InstantLabs® Listeria Species Food Safety Kit was validated against the International Organization for Standardization (ISO) reference method 11290-1 for the detection of Listeria monocytogenes and other Listeria species. The matrixes (stainless steel, sealed concrete, cheddar cheese, raw shrimp, and hot dogs) were inoculated with approximately 1 CFU/test portion of various Listeria species to generate fractional positives (5-15) in 20 inoculated samples. Enrichments were also fractionally inoculated with L. monocytogenes for side-by-side testing of the InstantLabs Listeria monocytogenes Food Safety Kit. Stainless steel and sealed concrete samples were validated using 4 × 4' and 1 × 1' test areas, respectively, and enriched in Buffered Listeria Enrichment Broth (BLEB) at 35 ± 1°C for 22-28 h. All food samples were tested at 25 g or 25 mL and enriched in BLEB at 35 ± 1°C for 24-28 h. All samples were confirmed using the ISO reference method, regardless of initial screen result. The InstantLabs test method performed as well as or better than the reference method for the detection of Listeria species on stainless steel, sealed concrete, cheddar cheese, raw shrimp, and hot dogs. Inclusivity and exclusivity testing revealed no false negatives and no false positives among the 80 Listeria species and 30 non-Listeria species examined. The method was shown to be robust when variations were introduced to the enrichment time, the volume for DNA extraction, and the heat block time (data not shown). Source


Sharma N.,InstantLabs Medical Diagnostics Corporation | Bambusch L.,InstantLabs Medical Diagnostics Corporation | Le T.,InstantLabs Medical Diagnostics Corporation | Morey A.,Food Safety Net Services Ltd. | And 3 more authors.
Journal of AOAC International | Year: 2014

The InstantLabs® Listeria monocytogenes Food Safety Kit was validated against the International Organization for Standardization (ISO) reference method 11290-1 for the detection of Listeria monocytogenes and other Listeria species. The matrixes (stainless steel, sealed concrete, ice cream, whole milk, cheddar cheese, raw shrimp, hot dogs, deli turkey, and lettuce) were inoculated with approximately 1 CFU/test portion of L. monocytogenes to generate fractional positives (5-15) in 20 inoculated samples. Enrichments were also fractionally inoculated with L. grayii for side-by-side testing of the Listeria Species Food Safety Kit. Stainless steel and sealed concrete samples were validated using 4 × 4' and 1 × 1' test areas, respectively, and enriched in Buffered Listeria Enrichment Broth (BLEB) at 35 ± 1°C for 22-28 h. All food samples were tested at 25 g and enriched in BLEB at 35 ± 1°C for 24-28 h. All samples were confirmed using the ISO reference method, regardless of initial screen result. The InstantLabs test method performed as well as or better than the reference method for the detection of L. monocytogenes on stainless steel and sealed concrete and in ice cream, whole milk, cheddar cheese, raw shrimp, hot dogs, deli turkey, and lettuce. Inclusivity and exclusivity testing revealed no false negatives and no false positives among the 50 L. monocytogenes serovars and 30 non-L. monocytogenes species examined. The method was shown to be robust when the enrichment times, volumes for DNA extraction, and heat block times were varied. Source


Bapanpally C.,SA Scientific Ltd | Maganty G.,SA Scientific Ltd | Khan S.,SA Scientific Ltd | Kasra A.,SA Scientific Ltd | Morey A.,Food Safety Net Services Ltd.
Journal of AOAC International | Year: 2014

The SAS™ Molecular Tests method for detection of Salmonella spp. in various food matrixes has been certified by the AOAC Research Institute and designated Performance Tested MethodSM No. 021202. The current method modification includes the optional immunomagnetic separation (IMS) to enrich the bacteria as well as optional visual fluorescence readout without the use of a turbidimeter. The modifications were validated against the U.S. Department of Agriculture/ Food Safety and Inspection Service Microbiology Laboratory Guidebook (MLG) and the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) reference methods. Food matrixes (chicken carcass rinse, beef trim, and spinach) were inoculated with low levels of Salmonella spp. (0.2-2 CFU/test portion) to generate fractional positives (5-15) in 20 inoculated samples. Samples were enriched with SAS Enrichment medium and incubated at 42 ± 1°C. Enrichments were tested directly and subjected to anti-Salmonella IMS prior to the SAS Molecular Tests. Results were determined via visual fluorescence and via turbidity using a turbidimeter. All replicates were confirmed using the MLG or BAM reference method procedures, regardless of presumptive result. The SAS Molecular Tests Salmonella Detection modified methods were determined to be equivalent to the reference methods for the detection of Salmonella in chicken carcass rinse, beef trim, and fresh spinach. The inclusion of IMS in the modified method improved the detection rate of Salmonella in chicken carcass rinses and spinach. The optional use of visual fluorescent reagent and heat block either with IMS or without IMS produced results that were comparable to the results obtained from using a real-time turbidimeter. Source


Bapanpally C.,SA Scientific Ltd | Maganty G.,SA Scientific Ltd | Khan S.,SA Scientific Ltd | Kasra A.,SA Scientific Ltd | Morey A.,Food Safety Net Services Ltd.
Journal of AOAC International | Year: 2014

The SAS™ Molecular Tests method for the detection of E. coli O157 in various food matrixes has been certified by the AOAC Research Institute and designated Performance Tested MethodSM No. 031203. The current method modification includes the optional immunomagnetic separation (IMS) to enrich the bacteria as well as optional visual fluorescence readout without the use of a turbidimeter. The following study was conducted to validate the proposed modifications against the U.S. Department of Agriculture/Food Safety and Inspection Service Microbiology Laboratory Guidebook (MLG) and the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) reference methods. E. coli O157:H7 ATCC 35150 and NM (non-motile) 700377 strains were used to inoculate the ground beef, beef trim, and spinach to obtain 20 low (0.23-2 CFU/test portion) and five high levels (3-5 CFU/test portion) of inoculations. Enriched samples were tested directly and subjected to anti-E. coli IMS prior to the SAS Molecular Tests. Results were determined via visual fluorescence and via turbidity using a turbidimeter. All the replicates, irrespective of the results, were confirmed using MLG 5.05 or BAM Chapter 4A methods. Results indicated that there were no significant differences in the detection of fractional positives (5-15 positives out of 20 replicates) with any of the methods tested above as compared to the reference methods. No false positives or negatives were detected except for two in the ground beef with IMS+Turbidity method. No false-negative samples were detected. Statistical analysis indicated that the modified methods were equivalent to the reference methods in detecting E. coli O157:H7 in the food matrixes tested. SAS Molecular Tests E. coli O157 Detection Kit can be used to detect E. coli O157:H7 in ground beef, beef trim, and spinach. The inclusion of IMS in the modified method improved the detection rate of E. coli O157:H7 in spinach and showed comparable detection rate in ground beef and beef trim. The optional use of visual fluorescent reagent and heat block either with IMS or without IMS produced results that were comparable to the results obtained from using a real-time turbidimeter. Source

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