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Most current disinfection strategies for fresh-cut industry are focused on the use of different chemical agents; however, very little has been reported on the effectiveness of the hurdle technology. The effect of combined decontamination methods based on the use of different sanitizers (peroxyacetic acid and chlorine dioxide) and the application of pressure (vacuum/positive pressure) on the inactivation of the foodborne pathogen E. coli O157:H7 on fresh-cut lettuce (Lactuca sativa) and carrots (Daucus carota) was studied. Fresh produce, inoculated with E. coli O157:H7, was immersed (4 °C, 2 min) in tap water (W), chlorine water (CW), chlorine dioxide (ClO2: 2 mg/L) and peroxyacetic acid (PAA: 100 mg/L) in combination with: (a) vacuum (V: 10 mbar) or (b) positive pressure application (P: 3 bar). The product quality and antimicrobial effects of the treatment on bacterial counts were determined both in process washing water and on fresh-cut produce. Evidence obtained in this study, suggests that the use of combined methods (P/V + sanitizers) results in a reduction on the microorganism population on produce similar to that found at atmospheric pressure. Moreover, the application of physical methods led to a significant detrimental effect on the visual quality of lettuce regardless of the solution used. Concerning the process water, PAA proved to be an effective alternative to chlorine for the avoidance of cross-contamination.

The shelf life of minimally processed potatoes (MPP) is limited by enzyme-catalyzed browning reactions, with the increase in respiration being another factor that affects quality retention of this product. Sulfites are commonly used as effective preservative agents in minimally processing potatoes, but ascorbic acid and citric acid are considered natural sulfite substitutes and more accepted by consumers. The aim of this study was to study the effect of combinations of the preservative agents cited above (sodium metabisulfite 0.1% and 0.5%; citric acid 0.1% and 0.5%; ascorbic acid 0.5%) on the respiration rate of MPP (cv. Monalisa) processed at both ambient and refrigerated temperatures. The results have revealed that there is a significant effect of dipping treatment and temperature on respiration rate of MPP. Sodium metabisulfite (SM) reduces respiratory activity up to 0.8 mL/kg/h. The addition of either citric or ascorbic acid enhanced the effect of SM on the reduction of the respiration rate of MPP. The strongest effect (up to 3.3 mL/kg/h) was observed when a combination of all 3 agents at the higher concentrations was employed at a temperature of 18 degrees C.

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.