Reduced time to detect Salmonella in peanut butter

Investigator: Arun K. Bhunia (Department of Food Science)

Project Report 2012 - 2013

Salmonella is an important cause of human illness in the United States, and children are the most likely to get salmonellosis. Following an outbreak of Salmonella infections linked to peanut butter in 20 states in 2012, in which over half of ill persons were children, ARS-funded researchers at Purdue University's Center for Food Safety Engineering in West Lafayette, Indiana, worked on improving the detection of Salmonella in peanut butter using a light scattering technology they developed. The optical light scattering sensor, BARDOT, is a noninvasive label-free detection system which allows identification of bacterial colonies in real-time. BARDOT has been used as tool to differentiate bacteria at genus, species, and serovars/serotype levels. A shortened enrichment protocol was developed for BARDOT-based detection of Salmonella serovars and applied to the analysis of peanut butter. The BARDOT technique was able to detect S. Typhimurium in peanut butter with 98% accuracy in 24 hours, returning results comparable to the USDA-FSIS method, which requires ~72 hours. This reduced time to detect Salmonella could improve the response time to illness outbreaks, as well as better facilitate analyses to prevent the distribution of contaminated foods.

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