Comparative analyses of sanitizing solutions on microbial reduction and quality of leafy greens

Improved postharvest sanitizing methods are needed to reduce foodborne disease outbreaks from leafy greens. The efficacy of different sanitizing solutions on microbial reduction and quality of leafy greens were evaluated. Lettuce leaves were inoculated with Escherichia coli or Listeria monocytogenes as model foodborne pathogens. The inoculated lettuce samples were treated with acidified sodium chlorite (ASC), sodium hypochlorite (SH), peracetic acid (PAA), or water using soaking and spraying techniques. For quality analysis, lettuce leaves were washed with water or sanitizing solutions and stored at 4 °C for 15 days. The soaking technique showed higher microbial reduction than the spraying techniques. The maximum microbial reduction for E. coli (3.94 log CFU/g) and L. monocytogenes (3.58 log CFU/g) was obtained by 5 min soaking of lettuce leaves in PAA, followed by ASC, SH, and water, respectively. A decrease in L* (dark/light) and an increase in a* (green/red) values were observed throughout 15 days of storage. The PAA and ASC caused less browning than the SH. In conclusion, PAA could be a better alternative to chlorine solutions for postharvest sanitization of fresh produce.