Evaluation of Combined Disinfection Methods for Reducing Escherichia coli O157:H7 Population on Fresh-Cut Vegetables

Abstract

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.

Neutral electrolyzed water (NEW), chlorine dioxide, organic acid based product, and ultraviolet-C for inactivation of microbes in fresh-cut vegetable washing waters

“…However, at 10 ppm the effect was not improved by a longer contact time. In the study by Petri, Rodriguez, and Garcia () ClO 2 at concentration of 2 ppm was insufficient for maintaining the microbial quality ( E. coli ) of wash water in the washing process for both fresh‐cut lettuce and shredded carrots.…”

Sanitization protocols applied to commercial restaurants: Effects on natural contaminant microbiota and Salmonella enterica Enteritidis adhered on tomatoes

“…All restaurants performed some hygiene procedure for vegetables. Washing and sanitizing fruits and vegetables are essential to prevent foodborne diseases (Petri et al, 2015). In this study, 91.66% (n = 11) of the restaurants use chlorinated compounds for their sanitization step, using one of four different brands of chlorinated compounds and sanitary water with the addition of 2.5% of sodium hypochlorite.…”

“…Among the sanitizers used in the food industry and restaurants, especially to wash fresh produce, chlorine and chlorinated compounds are often used (Rosário et al, 2017). Their ease of use, low cost, high antimicrobial activity and complete dissolution in water make chlorinated agents a common choice for a disinfectant in (Petri et al, 2015). In only one of the restaurants, a vinegar-based solution was followed by washing with water.…”

“…Vegetables provided in restaurants or as minimally processed are often linked to the origin of disease outbreaks because they are ready for consumption and are not subjected to sufficient processes to reduce microbial contamination. Thus, the use of effective chemical agents during the washing and sanitizing steps to ensure the safety of the products has gained more interest in the scientific community (Petri et al, 2015). A washing operation associated with the use of sanitizing solutions is considered the only process that can effectively reduce the number of spoilage-inducing and pathogenic microorganisms and contribute to the safety of the product (São José et al, 2014).…”

“…Chlorine and its diverse forms are the most frequently used disinfectants. Easily use, low cost, good antimicrobial activity and dissolution in water make chlorinated agents attractive for frequent use in sanitization step in industry and restaurants (Petri et al, 2015). The recommended total chlorine concentrations as a disinfectant agent range from 50 to 200 mg·L -1 (Ali et al, 2017) In Brazil, it is recommended at a concentration of 100 to 250 mg·L -1 for 15 min for the disinfection of vegetables (Oliveira et al, 2012).…”