Currently, sodium hypochlorite is the most used sanitizer in fresh-cut vegetable processing, but the formation of undesirable by-products, such as trihalomethanes that have negative impact on human health and environmental safety, is stimulating the scientific research to find alternative sanitization techniques to chlorine in fresh-cut processing.
The ozone in washing water could be a significant alternative to chlorine use because it does not leave residues in food, it decomposes quickly in non-toxic molecular oxygen and it is used at low concentrations. However, ozone efficacy in reducing microbial contamination depends on type of product, dose, application methods (ozonated water or gaseous), temperature, pH, relative humidity and presence of organic substances.
The aim of the work conducted by Amaral et al. (2012) was to find the most effective concentration of ozonated water to reduce the microbial contamination present on green pepper.
For the work, the green peppers were purchased in a local trade market of Campinas, then they were selected, washed and sliced into strips. The washing treatments were:
- unwashed slices (T1);
- slices washed with tap water (T2);
- slices washed with ozonated water at concentration of 1.6 mg/L ozone for 1 min (T3);
- slices washed with ozonated water at concentration of 1.8 mg/L ozone for 1 minn (T4).
Microbiological analyses (Salmonella spp. group, total count of psychrotrophic and mesophilic aerobic bacteria, total count of yeasts and molds, total coliforms and Escherichia coli) and physical-chemical analyses (pH and total soluble solids content) were carried out on minimally processed green pepper
Equipment for production of ozonated water: 1. Generating ozone cell; 2. Oxygen cilinder (99% of pureness); 3. Diffusing pipe; 4. Ozonated water exit.
The results has shown that the initial microbial contamination of the green pepper was composed by 1.3 x 105 CFU/g of mesophilic aerobic bacteria, by > 1.1 x 103 CFU/g of total coliforms, by < 10 CFU/g of psychrotrophic and yeasts and molds. After ozone treatment, the microbial load was significantly reduced, especially mesophilic aerobic bacteria (1.3 x 104 CFU/g) and total coliforms (9.2 x 10 CFU/g). The presence of E. coli and Salmonella spp. was not detected.
In regard to the green pepper internal quality, the pH is an important quality factor for fresh-cut vegetables and it can range from 4.9 to 6.9, in this work pH ranged from 6.00 (T4) to 6.18 (T1), while the total soluble solids content ranged from 4.00 (T3) to 4.50 (T1) °Brix.
Original study. Amaral R.D.A., Bachelli M.L.B., Zerbinati M.T., Benedetti B.C., ‘Effectiveness of different concentrations of ozonated water in the sanitization of fresh-cut green pepper’, September 2012, Agricultural Engineering International: CIGR Journa, Issue No. 14(3), pagg. 131-135. Further info: www.cigrjournal.org/index.php/Ejounral/article/viewFile/1559/1642