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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #362970
Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Inactivation of Salmonella on alfalfa seeds by benzyl isothiocyanate

Author
item YIN, HSIN-BAI - US Department Of Agriculture (USDA)
item BOOMER, ASHLEY - US Department Of Agriculture (USDA)
item CHEN, CHI-HUNG - US Department Of Agriculture (USDA)
item Patel, Jitu

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2019
Publication Date: 4/24/2019
Citation: Yin, H., Boomer, A., Chen, C., Patel, J.R. 2019. Inactivation of Salmonella on alfalfa seeds by benzyl isothiocyanate. BARC Poster Day. 57:72.

Interpretive Summary:

Technical Abstract: Salmonellosis outbreaks associated with alfalfa sprouts have occurred with increased frequency worldwide. It is critical to identify effective treatments for controlling Salmonella contamination on alfalfa seeds. The purpose of this study was to investigate the efficacy of benzyl isothiocyanate (BIT), a cruciferous vegetable-derived compound, for controlling Salmonella on alfalfa seeds. Alfalfa seeds (150 g) were immersed in 300 ml of sterile deionized water containing individual Salmonella serotypes Braenderup, Newport, Typhimurium, and Tennessee at two inoculation levels of 4 log or 6 log CFU/ml for 2 min. After overnight air-drying, 15 g of inoculated seeds were treated with 30 ml of 0%, 0.5%, 1%, 1.5%, or 2% of BIT solutions for 30 min. Inoculated seeds without any treatment (baseline) or 20,000 ppm of total chlorine were included as controls. After treatment, seeds were stored at 25°C for 7 days, and surviving Salmonella populations were determined on days 0, 1, 5, and 7 by plating on XLT4 agars. The effect of BIT on alfalfa seeds germination rate was evaluated using automated sprouting equipment. The antimicrobial effects of BIT against three serotypes of Salmonella on alfalfa seeds was concentration-dependent. The anti-salmonella activity of BIT at 1.5% and 2% level was comparable to 20,000 ppm chlorine on days 5 and 7. At the high inoculation level, ~4.5 log CFU/g Salmonella were recovered from the baseline on day 7; however, BIT at 2% significantly decreased pathogen populations to < 1.7 log CFU/g. S. Tennessee was the most sensitive among serotypes evaluated in this study. Germination rate of 0.5%-1.5% BIT treated alfalfa seeds (~80%) was not significantly different from control or chlorine-treated seeds (~86%). Results of the study indicate that BIT can potentially be used to control Salmonella contamination on alfalfa seeds.