MINIMIZING SALMONELLA CONTAMINATION IN SPROUTS BY CONTROLLING THE IRRIGATION CONDITIONS DURING GERMINATION

The objective of this study was to examine whether the proliferation of Salmonella can be minimized during sprouting by controlling the irrigation conditions using seeds that have been either treated or not treated with 20,000 ppm of calcium hypochlorite, Ca(OCl)2. 200 g of alfalfa seeds spiked with 2 g (or 1 %) of inoculated seeds (containting~1 log cfu/g of Salmonella) were allowed to germinate in a glass jar or in an automatic sprouter (EasyGreen) for 5 days at room temperature. The sprouts germinated in the automatic sprouters were irrigated with either sterile tap water or chlorinated water (containing 100 ppm of calcium hypochlorite) at various frequencies (once every 1, 2 or 4 h); the sprouts germinated in glass jar were rinsed every 24 h with sterile tap water. The same growth studies were performed on seeds treated with 20,000 ppm Ca(OCl)2 for 15 min prior to sprouting. Sprout samples were taken daily and analyzed for the level of Salmonella using the three-tube most probable number method as described in the FDA BAM. Seed treatment with 20,000 ppm Ca(OCl)2 reduced Salmonella level in seeds to a level that was below the detection limit (< -2.5 log MPN/g). The pathogen was not detected during five days of germination in automatic sprouters or jars. Using untreated seeds, the level of Salmonella changed from an increase of ~ 7 log MPN/g in sprouts grown in jars and irrigated once every 24 h to an increase of ~ 4 log MPN/g during sprouting in the automated sprouters and irrigated once every 1 h. Irrigation with chlorinated water although inhibited Salmonella re-growth but affected the quality of sprouts. Overall, seed treatment combined with frequent irrigation with tap water or chlorinated water can control the level of Salmonella to an undetectable level during sprouting.M.S. in Food Safety and Technology, July 201