Effect of Lactoperoxidase System on Microbiological and Quality Markers of Minimally Processed Lettuce

Minimally processed lettuce is sensitive to microbial attack caused by the loss of natural resistance and their high water content and nutrients. The use of natural anti-microbial agents such as the lactoperoxidase system (LPS) represents an interesting alternative to the use of chemical treatments. This study focused on the importance of LPS and its efficiency as a bioprotective agent. The effect of washing with LPS, at two different concentrations (4 and 5 IU) and four different treatment times (1, 2, 3 and 4 h) on microbial growth in fresh-cut lettuce, was determined at 30 ̊C and compared with a 80 ppm chlorine at 4 ̊C for 20 min. The results deduced that both doses of LPS showed significant reductions in microbial growth when applied during 4 h, but the highest dose proved to be more effective. No significant differences were found between the LPS treatment and chlorine considering native microflora reduction and quality markers during storage.