Effectiveness of household natural sanitizers in the elimination of Salmonella typhimurium on rocket (Eruca sativa Miller) and spring onion (Allium cepa L.)

Experiments were done with fresh lemon juice, vinegar and their mixture (1:1) to evaluate their efficacy in reducing the numbers of Salmonella typhimurium on fresh salad vegetables. Fresh whole rocket leaves and shredded spring onion samples were inoculated with S. typhimurium suspensions to provide initial populations of approximately 6 and 3 log cfu/g. After inoculation, vegetables were treated with the test solutions for 0, 15, 30 and 60 min, and pathogens were enumerated by using direct plating on Bismuth Sulphite Agar (BSA). Prior to this work, it was shown that BSA was not toxic for acid injured Salmonella cells by statistical analysis applied to enriched and non-enriched samples (P>0.05). Treatment of rocket leaves with fresh lemon juice and vinegar caused a significant reduction ranging between 1.23 and 4.17 log cfu/g and between 1.32 and 3.12 log cfu/g, respectively, while the maximum reduction reached by using lemon juice-vinegar mixture (1:1) for 15 min, which reduced the number of pathogens to an undetectable level. In the spring onion samples, lemon juice, vinegar and their mixture caused 0.87-2.93, 0.66-2.92 and 0.86-3.24 log cfu/g reductions, respectively.