Despite considerable research efforts towards the development of sprout seed-sanitizing methods there is still a need for highly effective, low-cost, easily implemented, and environmentally benign seed-sanitizing strategies that can be used by organic and conventional sprout growers. The use of 20,000 ppm Ca(OCl)2 presents worker and environmental safety concerns, may not always be effective in eliminating human pathogens from contaminated seed lots under commercial practice, and can be highly detrimental to the germination capacity of some seed types . The potential for internalization of bacterial human pathogens into sprouts during germination and growth from contaminated sprouting seed has been demonstrated, but the location of pathogens on naturally contaminated seed is still not known. Are the pathogens solely surfaceborne, sometimes entering into cracks and natural openings such as the hilum and micropyle in the seed coat, or are they also present internally in the seed coat as are some seedborne plant pathogenic bacteria ? The optimization and commercialization of biological control agents for use on sprouting seed as an alternative to chemical sanitizers is highly desirable.
The ecology of human pathogens on sprouts is not well defined and several questions remain unanswered. Are pathogens capable of forming biofilms on sprout surfaces or can they become part of biofilms formed by the native microflora making their eradication more problematic? What microbial cell surface components (e.g., curli, fimbriae, flagella, and extracellular polysaccharides such as colanic acid and cellulose) are important for the initial attachment to plant surfaces and subsequent biofilm formation? Does the plant react in any way to the presence of pathogens on surfaces or in internal tissues? Could sprout seed cultivars be developed that release high levels of antibacterial compounds upon germination that might inhibit growth and survival of pathogens?
Further research in the areas mentioned above should assist in the development of improved strategies for reducing the risk of future foodborne outbreaks allowing for greater consumer confidence in the microbiological safety of sprouts and ensuring the survival of a strong sprout industry worldwide. Intervention strategies developed for seeds and sprouts may also be applicable to ensuring the microbiological safety of other types of produce.
Was this article helpful?