Bactericidal Activity of Isothiocyanate Against Pathogens On Fresh Produce

Bactericidal Activity of IsothiocyanateAgainst Pathogens on Fresh Produce

January 2000

Journal of Food Protection: Vol. 63, No. 1, pp. 25­30.




Thebactericidal activity of allyl and methyl isothiocyanate (AITC and MITC) wastested with a rifampicin-resistant strain of Salmonella Montevideo andstreptomycin-resistant strains of Escherichia coli O157:H7 and Listeriamonocytogenes Scott A.  Iceberg lettuce inoculated with high (107 to 108CFU/g) and low (103 to 104 CFU/g) concentrations of bacterial pathogens wastreated with AITC and MITC in sealed containers at 4°C for 4 days.  AITCshowed stronger bactericidal activity than MITC against E.coli O157:H7 andSalmonella Montevideo, whereas MITC showed stronger activity against L.monocytogenes than E. coli O157:H7 and Salmonella Montevideo.

Up to 8-log reduction occurred with E.coli O157:H7 andSalmonella Montevideo on lettuce following treatment with vapor generated from400 [Image]l of AITC for 2 and 4 days, respectively. AITC was used to treattomatoes inoculated with Salmonella Montevideo on stem scars and skin and applesinoculated with E. coli O157:H7 on stem scars. The bactericidal effect of AITCvaried with bacteria species and exposure time.

Salmonella Montevideo inoculated on tomato skin was moresensitive to AITC than that on stem scars.

Treatment with vapor generatedfrom 500 [Image]l of AITC caused an 8-log reduction in bacteria on tomato skinbut only a 5-log reduction on tomato stem scars. The bactericidal activity ofAITC was weaker for E. coli O157:H7 on apple stem scars; only a 3-log reductionin bacteria occurred when 600 [Image]l of AITC was used.