Study of the bactericide effects of the ultra-high frequency field and antimicrobial thermoformed rigid consumers' tare on the sanitary significant microflora of the packed curds

Positive effect of the ultra-high frequency energy application in the food technologies is defined not only by processes accleleration but also by some certain impacts on the microbiological objects. Known theoretical suppositions of the bactericide effects of the ultra-high frequency field are not monosemantic. Effects of the field on the sanitary important microflora of the products in the packaging materials with antimicrobial additives were also actively investigated. The impacts of the UHG-field at the defrosting of the curds and antimicrobial additive of the packaging material were studied. Four test samples were investigated reflecting combination of the effects of the UHF-field at defrosting and of the antimicrobial additives to the packaging material and their separate effects as well as defrosting of the packed curds in the air without additional factors influence-control. The packed curds was frozen at -25 °C and was defrosted under the action of the UHF field and in the air after 2,14 and 30 days of low temperature storage .Changes of the microbiological indices in the experimental samples were compared with the indices of the fresh curds. It was demonstrated that application of the UHF-field at curds defrosting results in reduction of the E. coli count by 1-2 orders. Besides, depending on the starting count, quantity of the E.coli decrease was more considerable than the higher its starting count was. Bacteriostatic effect of the UHF-field on yeasts was noted closer to the 30 days of reservation Impacts of the antimicrobial package on the E.coli count lowering in the mass of the packed product were observed at the low temperature storage not earlier than after 30 days and it probably depends on the total mass of the product packed. Synergistic effects of the UHF field and antimicrobial additive on the level of the sanitary significant microflora in the mass of the product were not established in the research work.

curds, ultra-high frequency fields, antimicrobial additives, packaging materials, storage, defrosting, low temperature, bacteriostatic effect