The Thai Journal of Veterinary Medicine


This study was conducted to evaluate the effectiveness of five chemical disinfectants, including sodium hypochlorite (CL), trisodium phosphate (TSP) and organic acids; acetic acid (AA), citric acid (CA) and lactic acid (LA), in reducing of the contamination level of Salmonella enterica Serovar Enteritidis (S. Enteritidis) on chicken skin. Chicken drumsticks were artificially contaminated with the kanamycin resistant S. Enteritidis (SEnKmr) to obtain 105-106 CFU/cm2. The five disinfectants used were: CL; 25, 50 and 100 ppm, TSP; 4, 8 and 12%, AA, LA and CA; 0.6, 1.2 and 2.4%. The disinfectants were applied by either dipping for 1, 3 and 5 min or spraying for 10 s. The number of viable cells were enumerated after 30 min incubation at room temperature (RT;ca 25oC) and compared to that from untreated controls. The results showed good potential for 4% and 8% TSP and 0.6% and 1.2% acetic acid, lactic acid and citric acid, as disinfectants that caused no changes in the physical appearance of the skin. Serovar Enteritidis cells were inhibited most when dipped for 5 min or sprayed with 2.4% acetic acid (1.70 and 1.78 log CFU/cm2 reduction, respectively). Chicken carcasses sprayed with 2.4% AA were further investigated by storage at RT for 1, 6 and 24 h and at 4oC for 1, 24, 72 and 120 h. The surviving cells were enumerated at the specified times. Storage at 4oC produced a rapid loss of viable cells, with no detectable viability after 120 h. A combination of spraying with disinfectants and 4oC storage prolonged the activity of the disinfectants. The results support the benefit of decontamination and warrant further research.

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