Comparison of peracetic acid and chlorine effectiveness during fresh-cut vegetables processing at industrial scale
This study was conducted to compare the efficacy of two sanitizing agents (chlorine and PAA) in reducing (both spoilage and pathogenic) microorganisms and in reducing disinfection by-products ( DBPs) in the washing stage of three types of minimally processed vegetables: Iceberg lettuce, carrots and baby leaves. These fresh-cut products are consumed uncooked and, hence, a proper sanitation is essential in preventing food-borne illness outbreaks. The comparison was done at industrial scale, using equipment already present in the fresh-cut industry and washers designed and manufatured for this purpose. Results showed that, regarding washing water hygiene and final product microbial quality, the use of PAA had a similar efficacy than chlorine. Different scenarios (SCN) combining PAA, chlorine and water have been tested simulating the current industrial processes for each one of the tested vegetables. Overall, results confirmed that the use of a sanitizer, PAA or chlorine, in the washing water of the three tested vegetables is effective for the prevention of cross-contamination during the washing process and hence, to guarantee produce food safety. Regarding final product microbiological quality and shelf life, the use of chlorine or PAA showed no significant differences in lettuces neither in baby leaves. Regarging the potential formation of chlorinated DBPs in processing water, they were found not in significant amounts when washing water was treated with PAA in all scenarios and vegetables tested. Washing with 80 mg/L chlorine generated important amounts of THMs, chlorates and chlorites. While chlorates and chlorites were always below the recommended levels or legal limits established for drinking water, THMs exceeded these legal limits . With respect to perchlorates, values were below the quantification limit in all SCNs. Results obtained in the present study show that PAA is a reliable alternative to chlorine disinfection strategies in the fresh-cut industry.