Comparison of Chlorine and a Produce Wash Product for Effectiveness in Killing Salmonella and Ecoli On Alfalfa Seeds

Comparisonof Chlorine and a Prototype Produce Wash Product for Effectiveness in KillingSalmonella and Escherichia coli O157:H7 on Alfalfa Seeds

Journalof Food Protection: 2001, Vol. 64, No. 2, pp. 152-158. 

LarryR. Beuchat, Center for Food Safety and Quality Enhancement, Department ofFood Science and Technology, University of Georgia,
Thomas E. Ward and Charles A. Pettigrew, The Procter and Gamble Company, SharonWoods Technical Center

Abstract-Outbreaks of Salmonella and Escherichia coli O157:H7 infectionsassociated with alfalfa and other seed sprouts have occurred with increasedfrequency in recent years. This study was undertaken to determine the efficacyof a liquid prototype produce wash product (Fit), compared with water andchlorinated water, in killing Salmonella and E. coli O157:H7 inoculated ontoalfalfa seeds. We investigated the efficacy of treatments as influenced by seedsfrom two different lots obtained from two seeds suppliers and by two methods ofinoculation. The efficacy of treatments was influenced by differences in seedlots and amount of organic material in the inoculum. Significant ( = 0.05) reductions in Salmonellapopulations on seeds treated with 20,000 ppm of chlorine or Fit for 30 minranged from 2.3 to 2.5 log10 CFU/g and 1.7 to 2.3 log10CFU/g, respectively. Reductions ( = 0.05) in E. coli O157:H7ranged from 2.0 to 2.1 log10 CFU/g and 1.7 to more than 5.4 log10CFU/g of seeds treated, respectively, with 20,000 ppm of chlorine or Fit.Compared with treatment with 200 ppm of chlorine, treatment with either 20,000ppm of chlorine or Fit resulted in significantly higher reductions inpopulations of Salmonella and E. coli O157:H7. None of the treatments eliminatedthese pathogens as evidenced by their detection on enrichment of treated seeds.Considering the human health and environmental hazards associated with the useof 20,000 ppm of chlorine, Fit provides an effective alternative to chlorine asa treatment to significantly reduce bacterial pathogens that have beenassociated with alfalfa seeds.