Influence of aqueous ozone, blanching and combined treatments on microbial load of red bell peppers, strawberries and watercress

Abstract

a b s t r a c tThe effectiveness of ozone in aqueous solution treatment on microbial inactivation was studied for three combinations microorganism/food: Listeria innocua/red bell peppers (artificially inoculated), total mesophiles/strawberries, and total coliforms/watercress, with two concentrations (0.3 and 2.0 ppm). Blanching treatments (50-60°C) were also individually applied and in combination with ozone, for studying possible synergistic effects. In relation to ozone treatments, the highest microbial reductions were obtained for the highest concentration with the highest treatment time (3 min). Under those conditions, L. innocua/peppers, total mesophiles/strawberries and total coliforms/watercress were reduced respectively 2.8 ± 0.5, 2.3 ± 0.4 and 1.7 ± 0.4 log-cycles. However, a substantial portion of the microbial populations were reduced by water washing alone, and the presence of ozone generally added an additional reduction of 0.5-1.0 log-cycles.If ozone at the highest concentration is used, the treatment impacts on L. innocua/peppers and total mesophiles/strawberries load reductions were equivalent to a blanching at 50°C (for the same treatment times).Combining blanching and ozone did not generate synergistic effects, and in some situations microbial reductions were lower than the ones observed when treatments were applied independently.

The effect of thermal, chlorine and ozone treatments on survival of Escherichia coli and Salmonella spp. in açai berries

“…In the second assay, açai berries were blanched at 90 °C and cooled with different aqueous sources (Figure 1). The ratio between the sample mass and the volume of water used in all test solutions for açai berries treatment was 40 g.L -1 (12). The recovered microbial enumeration from berries of two assays was performed before decontamination treatments (N 0 ).…”

“…The efficiency of chlorination can be influenced by organic matter present in water, as well as insufficient cooling, exposure to air or light, or a combination of these three factors [11]. Ozone (O 3 ) is one of the most powerful oxidizing agents (2.07 mV), effective for inactivation of Gram-negative and Gram-positive bacteria, viruses and yeasts, including sporulated forms [12], and protozoan cysts [13]. Studies have shown that treatment with ozonated water extends the shelf life of various food products, increasing quality and food safety [14; 15].…”

“…The effect of thermal, chlorine and ozone treatments on survival 5 decomposition in water, its antimicrobial action can be very effective for surface decontamination of fruits and vegetables [12].…”

Evaluation of the effectiveness of ozone as a sanitizer for fish experimentally contaminated with Salmonella sp.

“…In addition, several studies have shown that its use presents low potential with regard to changes in the sensory characteristics of food, which expands the possibilities for its use (USEPA, 1999;WHANG et al, 2004;ALEXANDRE et al, 2011;MUKHOPADHYAY;RAMASWAMY, 2012).…”

Evaluation the Effect of Processing and Storage on Some of the Nutrients of Selected Varieties of Legume Sprouts in Sri Lanka

“…Application of minimal thermal processing such as hot water blanching is a better option to reduce the initial microbial flora [3] associated with the raw sprouts of legumes, and to preserve the natural color and the appearance of legume sprouts. Also it has been reported by many authors that, blanching not only reduce the initial microbial load but also improve the quality of fresh product but also it retains physical quality during low temperature storage while minimize the losses of nutrients as it is a mild heat treatment.…”