Current Intervention Strategies for the Microbial Safety of Sprouts

Sprouts have gained popularity worldwide due to their nutritional values and health benefits. The fact that their consumption has been associated with numerous outbreaks of foodborne illness threatens the $250 million market that this industry has established in the United States. Therefore, sprout manufacturers have utilized the U.S. Food and Drug Administration recommended application of 20,000 ppm of calcium hypochlorite solution to seeds before germination as a preventative method. Concentrations of up to 200 ppm of chlorine wash are also commonly used on sprouts. However, chlorine-based treatment achieves on average only 1- to 3-log reductions in bacteria and is associated with negative health and environmental issues. The search for alternative strategies has been widespread, involving chemical, biological, physical, and hurdle processes that can achieve up to 7-log reductions in bacteria in some cases. The compilation here of the current scientific data related to these techniques is used to compare their efficacy for ensuring the microbial safety of sprouts and their practicality for commercial producers. Of specific importance for alternative seed and sprout treatments is maintaining the industry-accepted germination rate of 95% and the sensorial attributes of the final product. This review provides an evaluation of suggested decontamination technologies for seeds and sprouts before, during, and after germination and concludes that thermal inactivation of seeds and irradiation of sprouts are the most practical stand-alone microbial safety interventions for sprout production.