Acidified Sodium Chlorite as an Alternative to Chlorine for Elimination of Salmonella on Alfalfa Seeds

ABSTRACT:  The health and environmental hazard associated with the use of chlorine for food processing has been documented previously. This study was conducted to determine if acidified sodium chlorite (ASC) could be used to replace calcium hypochlorite (CaOCl]₂) for disinfection of alfalfa seeds. Contaminated seeds containing approximately 1.5 × 10⁷ CFU/g of Salmonella were treated with ASC or Ca(OCl)₂ at different concentrations and for different periods of time. Results showed that the efficacy of ASC and Ca(OCl)₂ for elimination of Salmonella on contaminated seeds could be improved greatly by extending the treatment time from the traditional 15 to 45 min. Treatment of seeds with 800 ppm of ASC for 45 min reduced the number of Salmonella by 3.9 log units, approximately 1.2 log units higher than that treated with 20000 ppm of Ca(OCl)₂. Treatment of seeds with a lower concentration (100 to 400 ppm) of ASC for 45 min reduced the number of Salmonella by 1.3 to 2.2 log units. Soaking alfalfa seeds in 800 ppm of ASC for 45 min did not affect seed germination. However, soaking seeds in 20000 ppm of Ca(OCl)₂ for 45 min reduced seed germination by 20%. Unlike Ca(OCl)₂, antimicrobial efficiency of ASC was not affected by pre-exposure to alfalfa seeds. Data presented also showed that Salmonella on newly inoculated seeds that had been stored at 4 °C for less than 7 d were more sensitive to sanitizer treatment than those on seeds that had been stored for 4 wk or longer.