Effects of ozone and chlorine washes and subsequent cold storage on microbiological quality and shelf life of fresh parsley leaves

Abstract

In this study, we evaluated the effects of ozone and chlorine washes on the inactivation of Escherichia coli and Listeria innocua and on color pigments and antioxidant compounds of fresh parsley leaves. The growth of the microorganisms and the changes in pigments and antioxidant compounds of the leaves during subsequent cold storage for 15 days were also investigated. The microbial reductions obtained with ozone treatments were approximately 1 log higher than those obtained with distilled water. Chlorine was more effective against E. coli than ozone (3.2 and 2.2 log reductions, respectively) however reductions in L. innocua counts obtained with chlorine and ozone were not significantly different (P > 0.05). Washing treatments tested in this study did not have any detrimental effect on the pigments and antioxidant compounds of parsley leaves. However, these characteristics showed descending trends during subsequent cold storage. Decreases reached up to 45, 39, 88, 33 and 35% in chlorophyll a, chlorophyll b, ascorbic acid and total phenolic contents and antioxidant activity, respectively, at the end of storage. We determined that E. coli counts steadily decreased, however, L. innocua counts were quite stable during storage which can pose a serious food safety risk associated with parsley. © 2020 Elsevier Ltd