Assessment of the efficiency of ozonated water as bacterial contamination reduction tool in a pork cutting plant
International Conference on the Epidemiology and Control of Biological, Chemical and Physical Hazards in Pigs and Pork
The food industry is constantly searching for new tools to reduce bacterial contamination in the plants. In this study we assessed the efficiency of ozonated water as a tool to improve reduction of residual bacterial contamination in a pork cutting plant as a complement of sanitation procedures. First, the effectiveness of the ozonated water was tested on conveyors to reduce residual Salmonella, coliforms and aerobic flora load. Three conveyors were selected in the cutting rooms. Ten samples of
... oms. Ten samples of 300 cm 2 were collected before and after water or ozonated water rinse. Aerobic flora and coliforms counts were done using petrifilms (3M) and Salmonella were detected using the MFLP-75 Health Canada method. In all the samples, Salmonella couldn't be detected and coliforms counts were below technical threshold limit. Aerobic flora results were compared after water and ozonated water treatments. A statistically significant benefit of 0.64 cfu / 300 cm 2 for ozonated water rinse was measured on one of the conveyor (t-test p < 0.05). This strategy was also evaluated as a way to eliminate Listeria monocytogenes that persists after cleaning and disinfecting operations. Sixteen contaminated sites after these operations were selected. They consisted in surfaces on the equipment and conveyors of the cutting rooms and non-contact surfaces. Each site was divided in two parts; one half receiving a 3.5 ppm ozonated water treatment (10 seconds application), the second part received a water rinse as control. Two to eight swabs were collected on each site. Listeria monocytogenes detection was conducted using MFHPB-30 Health Canada method. No statistically significant differences (χ² > 0.05) were measured with 62.5 % (10/16) of sites and 37.7 % (26/69) of samples contaminated without treatment and 75 % (12/16) and 39.1 % (27/69) respectively after treatment. Results show that, in these conditions, the benefit of a supplementary ozonated water treatment in the cutting room is low and has no industrial relevance. This could be caused by the presence of residual organic matter on the surfaces, which reacts with ozone molecules.