HYPOCHLORITE ACTION AGAINST LACTIC ACID BACTERIA.

ARENA ME; SAVINO MJ; MANCA DE NADRA MC

BIOCELL

INCA

Lugar: Mendoza; Año: 2005 vol. 29 p. 77 - 77

0327-9545

 PUBLICACION DE RESUMEN The aim of disinfection is to eliminate microorganisms present on food-contact surfaces thereby avoiding contamination of raw materials and products with spoilage or pathogens organisms. Sodium hypochlorite (NaClO) is one of the compounds more used for this practice. The objective of this work is to study the effect of different concentrations of comercial NaClO in the development of lactic acid bacteria (LAB) and to determine the minimun inhibitory concentration (MIC). The NaClO concentrations were in % v/v: 0.1; 0.5; 1; 2; and 5 in the Möeller culture media pH 6.8. Cell growth was determined spectrofotometricaly at 560nm and by ufc/ml. The lowest concentration that inhibits bacterial growth during 24 h incubation was 0.5%. Two species of Lactobacillus developed after the lag phase of 24 h. After a contact time of 48 h with the corresponding MIC concentration of NaClO, 0,5% for coccus and 1% for  bacillus, LAB were grown in agar media without NaClO. Colonies developed with a delay of 48 h related to control medium. These results indicate the bacteriostatic effect of NaClO. However its strong oxidant property, that act producing  proteins denaturalization and  nucleic acids and enzymes inactivation, the resistant cell wall of LAB and the acidification of the culture media by the bacterial metabolism, promotes chloro evaporation with the consequent lose of disinfectant activity. The aim of disinfection is to eliminate microorganisms present on food-contact surfaces thereby avoiding contamination of raw materials and products with spoilage or pathogens organisms. Sodium hypochlorite (NaClO) is one of the compounds more used for this practice. The objective of this work is to study the effect of different concentrations of comercial NaClO in the development of lactic acid bacteria (LAB) and to determine the minimun inhibitory concentration (MIC). The NaClO concentrations were in % v/v: 0.1; 0.5; 1; 2; and 5 in the Möeller culture media pH 6.8. Cell growth was determined spectrofotometricaly at 560nm and by ufc/ml. The lowest concentration that inhibits bacterial growth during 24 h incubation was 0.5%. Two species of Lactobacillus developed after the lag phase of 24 h. After a contact time of 48 h with the corresponding MIC concentration of NaClO, 0,5% for coccus and 1% for  bacillus, LAB were grown in agar media without NaClO. Colonies developed with a delay of 48 h related to control medium. These results indicate the bacteriostatic effect of NaClO. However its strong oxidant property, that act producing  proteins denaturalization and  nucleic acids and enzymes inactivation, the resistant cell wall of LAB and the acidification of the culture media by the bacterial metabolism, promotes chloro evaporation with the consequent lose of disinfectant activity. The aim of disinfection is to eliminate microorganisms present on food-contact surfaces thereby avoiding contamination of raw materials and products with spoilage or pathogens organisms. Sodium hypochlorite (NaClO) is one of the compounds more used for this practice. The objective of this work is to study the effect of different concentrations of comercial NaClO in the development of lactic acid bacteria (LAB) and to determine the minimun inhibitory concentration (MIC). The NaClO concentrations were in % v/v: 0.1; 0.5; 1; 2; and 5 in the Möeller culture media pH 6.8. Cell growth was determined spectrofotometricaly at 560nm and by ufc/ml. The lowest concentration that inhibits bacterial growth during 24 h incubation was 0.5%. Two species of Lactobacillus developed after the lag phase of 24 h. After a contact time of 48 h with the corresponding MIC concentration of NaClO, 0,5% for coccus and 1% for  bacillus, LAB were grown in agar media without NaClO. Colonies developed with a delay of 48 h related to control medium. These results indicate the bacteriostatic effect of NaClO. However its strong oxidant property, that act producing  proteins denaturalization and  nucleic acids and enzymes inactivation, the resistant cell wall of LAB and the acidification of the culture media by the bacterial metabolism, promotes chloro evaporation with the consequent lose of disinfectant activity.