Comparison of antimicrobial efficacy of commercial sanitizers against E. coli O157:H7 and Salmonella on baby spinach

Aim: In this study, it was aimed to determine the antimicrobial effects of commercial sanitizers on Salmonella and E. coli O157:H7 pathogens in baby spinach. Materials and Methods: Baby spinach leaves were experimentally contaminated with Salmonella and E. coli O157:H7 pathogens using the spot inoculation method and allowed to adhere to the baby spinach surface for 2 hours at room temperature. For the sanitation of contaminated baby spinach samples, the following treatments were applied: control (group 1, without any treatment), sodium hypochlorite and active chlorine-containing agents (group 2), potassium salts-containing agents (group 3), chlorine-only agents (group 4), and thyme oil, sunflower lecithin, and lactic acid containing (group 5) commercial sanitizers. The antimicrobial efficacy of the treatments was evaluated, initially after contacting with 1, 5 and 10 minutes, and after 1 day (24 hours) stored at 4 °C. Results: All the treatment groups were more effective in reducing the Salmonella and E. coli O157:H7 load than control group (P<0.05). The group 2 and group 4 was the most effective in inhibiting Salmonella and E. coli O157:H7 after applying sanitizers for 10 minutes, showing reduction of 2,75 log cfu/cm2 and 2,55 log cfu/cm2, respectively (P<0,05). Following storage of baby spinach at 4 °C for 24 hours, the highest in inhibiting Salmonella and E. coli O157:H7 was determined in group 4, decreasing of 3,22 log cfu/cm2 and 3,09 log cfu/cm2, respectively (P<0,05). Conclusion: The results obtained show that commercial sanitizers are varied levels of antimicrobial effects depending on the contact time and storage time against Salmonella and E. coli O157:H7 pathogens. Although these sanitizers caused a reduction of >1 log in the loads of Salmonella and E. coli O157:H7 on spinach, none of these solutions, individually, proved to be effective in reducing the counts of recommended pathogens (>5 log) to meet microbiological criteria for safety and health. Key Words: Baby spinach, sanitizer, Salmonella, E. coli O157:H7