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Deng K, Wang SS, Kiener S, Smith E, Chen KS, Pamboukian R, Laasri A, Pelaez C, Ulaszek J, Kmet M, De Jesus A, Hammack T, Reddy R, Wang H. Multi-laboratory validation study of a real-time PCR method for detection of Salmonella in baby spinach. Food Microbiol 2023; 114:104299. [PMID: 37290875 DOI: 10.1016/j.fm.2023.104299] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 06/10/2023]
Abstract
The FDA Bacteriological Analytical Manual (BAM) Salmonella culture method takes at least 3 days for a presumptive positive result. The FDA developed a quantitative PCR (qPCR) method to detect Salmonella from 24-h preenriched cultures, using ABI 7500 PCR system. The qPCR method has been evaluated as a rapid screening method for a broad range of foods by single laboratory validation (SLV) studies. The present multi-laboratory validation (MLV) study was aimed to measure the reproducibility of this qPCR method and compare its performance with the culture method. Sixteen laboratories participated in two rounds of MLV study to analyze twenty-four blind-coded baby spinach test portions each. The first round yielded ∼84% and ∼82% positive rates across laboratories for the qPCR and culture methods, respectively, which were both outside the fractional range (25%-75%) required for fractionally inoculated test portions by the FDA's Microbiological Method Validation Guidelines. The second round yielded ∼68% and ∼67% positive rates. The relative level of detection (RLOD) for the second-round study was 0.969, suggesting that qPCR and culture methods had similar sensitivity (p > 0.05). The study demonstrated that the qPCR yields reproducible results and is sufficiently sensitive and specific for the detection of Salmonella in food.
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Affiliation(s)
- Kaiping Deng
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 6502 S. Archer Rd, Bedford Park, IL, 60501, USA
| | - Shizhen Steven Wang
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 5001 Campus Dr, College Park, MD 20740, USA
| | - Shannon Kiener
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 6502 S. Archer Rd, Bedford Park, IL, 60501, USA
| | - Emily Smith
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 6502 S. Archer Rd, Bedford Park, IL, 60501, USA
| | - Kai-Shun Chen
- FDA-Office of Regulatory Affairs (ORA), 109 Holton Street, Winchester, MA, 01890, USA
| | - Ruiqing Pamboukian
- FDA-Office of Regulatory Affairs (ORA), 12420 Parklawn Dr, Rockville, MD, 20857, USA
| | - Anna Laasri
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 5001 Campus Dr, College Park, MD 20740, USA
| | - Catalina Pelaez
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 6502 S. Archer Rd, Bedford Park, IL, 60501, USA
| | - Jodie Ulaszek
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 6502 S. Archer Rd, Bedford Park, IL, 60501, USA
| | - Matthew Kmet
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 6502 S. Archer Rd, Bedford Park, IL, 60501, USA
| | - Antonio De Jesus
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 5001 Campus Dr, College Park, MD 20740, USA
| | - Thomas Hammack
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 5001 Campus Dr, College Park, MD 20740, USA
| | - Ravinder Reddy
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 6502 S. Archer Rd, Bedford Park, IL, 60501, USA
| | - Hua Wang
- FDA-Center for Food Safety and Applied Nutrition (CFSAN), 5001 Campus Dr, College Park, MD 20740, USA.
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