Scientists at Ankara University (Turkey) have compared the efficacy of three washing treatments on microbial inactivation, especially against Escherichia coli and Listeria innocua, and have evaluated their effects on some chemical characteristics, such as chlorophyll, ascorbic acid and total phenolic contents and antioxidant activity, of fresh-cut lettuce, spinach and parsley.
Washing treatments consisted of using:
• distilled water
• ozonated water with 12 mg/L of ozone
• chlorinated water with 100 mg/L of chlorine.
Afterwards, the scientists have also evaluated the efficacy of a gaseous ozone treatment (950 µl/L) for 20 minutes on microbial inactivation and chemical characteristics of fresh-cut parsley. The gaseous ozone treatment was performed in a 4L glass chamber.
Results showed that both ozonated and chlorinated water allowed to reduce Escherichia coli by 2 and 2.9 log units, respectively; while the efficacy in Listeria innocua inactivation was similar for both washing treatments (2.2-2.3 log units).
As regards gaseous ozone treatment, it allowed to reduce both bacteria by 1-1.5 log units, however it showed an impact significantly negative on total phenolic and ascorbic acid content and antioxidant activity, whose values resulted less than those measured in control samples.
