Efficacy of nanoemulsified benzyl isothiocyanate and carvacrol in reducing Salmonella contamination and preserving quality in alfalfa seeds and sprouts

Authors: Oh, Sookyung; Patel, Jitendra

Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2025
Publication Date: 4/23/2025
Citation: Oh, S., Patel, J.R. 2025. Efficacy of nanoemulsified benzyl isothiocyanate and carvacrol in reducing Salmonella contamination and preserving quality in alfalfa seeds and sprouts. Foodborne Pathogens and Disease. https://doi.org/10.1089/fpd.2025.0006.
DOI: https://doi.org/10.1089/fpd.2025.0006

Interpretive Summary: Alfalfa sprouts have been implicated in multistate outbreaks of Salmonella infections. Treatment of seeds with diluted chlorine is recommended to control pathogens and reduce the risk of infection. If the concentration of chlorine is too high, it can reduce the germination rate. We tested alternatives less likely to harm germination. One was a compound found naturally in vegetables like cabbage and broccoli. Another was a compound found in herbs like thyme and oregano. Seeds were inoculated with high and low levels of Salmonella, followed by treatment with these two alternative compounds separately. The seeds were germinated in seed sprouters. Both natural compounds significantly reduced the level of Salmonella on both seeds and sprouts. At the low Salmonella contamination level, the compound from cabbages and broccoli lowered the Salmonella to undetectable levels. Treatment with either of the two natural compounds (from vegetables or from herbs) did not negatively affect either the germination rate or the appearance, weight, length, or width of the sprouts. These findings highlight the potential of these compounds for reducing Salmonella contamination on alfalfa sprouts without reducing the germination rate where the method can be used by the fresh produce industry to reduce food safety risks.

Technical Abstract: This study evaluated the efficacy of nanoemulsified benzyl isothiocyanate (NBIT) and carvacrol (NCR) to reduce Salmonella contamination on alfalfa seeds and sprouts. Given the susceptibility of sprouts to microbial contamination during germination, improved interventions were needed to enhance food safety without compromising product quality. NBIT and NCR were applied to Salmonella-inoculated seeds at high (6 log CFU/g) and low (2 log CFU/g) inoculum levels, and their impact on Salmonella populations, seed germination, sprout quality (length and weight), and visual appearance was assessed. Results revealed that both NBIT and NCR significantly reduced Salmonella populations and most treatments did not adversely affect seed germination or sprout quality. Treatment with 2.0% NBIT achieved reductions of up to 2.4 log CFU/g on seeds and 6.4 log CFU/g on sprouts at the low inoculum level. However, treatment with 2.0% NBIT resulted in an 18.8% reduction in germination occurred at the high inoculum level and a 10.7% reduction at the low inoculum level, along with a slight decrease in sprout size. In contrast, treatments with 0.5% and 1.0% NBIT, as well as 2.0% NCR, reduced Salmonella on seeds by 1.5 to 2.0 log CFU/g, regardless of inoculum level, and achieved reductions of 5.0 to 6.4 log CFU/g on sprouts at the low inoculum level. In addition, NBIT (0.5% and 1.0%) and NCR (2.0%) preserved seed germination rates and sprout quality metrics, including length, weight, and visual appearance, comparable to untreated controls. These findings highlight the potential of NBIT and NCR as effective antimicrobial agents for improving the microbial safety of alfalfa sprouts without compromising quality.