Wrinkled alfalfa seeds harbor more aerobic bacteria and are more difficultto sanitize than smooth seeds

At least 14 separate outbreaks of food poisoning attributed to either Salmo nella enterica or Escherichia coli O157:H7 have been traced to sprouts in t he past decade. Seeds contaminated with human pathogens caused most of thes e outbreaks, thus many sprout growers are now treating alfalfa seeds with t he sanitizing agent. calcium hypochlorite (Ca[OCl](2)). prior to sprouting. The efficacy of alfalfa seed sanitation varies between seed lots and betwe en seeds within each lot. Alfalfa seeds from different seed lots were sorte d by type in an effort to determine if certain seed types carry more aerobi c bacteria than other seed types. Seeds with a wrinkled type, characteristi c of lygus bug damage, had significantly higher levels of culturable aerobi c bacteria and were more difficult to sanitize than smooth, healthy seeds. After sanitation, wrinkled alfalfa seeds that had been inoculated with S. e nterica set. Newport carried significantly higher levels of Salmonella Newp ort than smooth seeds. If S. enterica is present on wrinkled seeds in natur ally contaminated seed lots, it may be difficult to chemically sanitize the seed lot. Removal of the wrinkled alfalfa seeds from the seed lots. perhap s by adapting color sorting equipment similar to that used to sort rice gra ins and other seeds, should reduce the level of aerobic bacteria in seed lo ts and may result in lower levels of human pathogens on contaminated alfalf a seeds.