Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2013

Organic acids reduce Salmonella on chicken meat more effectively than hydrochloric acid due to non-pH related effects (#306)

Sin Mei Tan 1 , Sui Mae Lee 1 , Gary Dykes 1
  1. Monash University, Bandar Sunway, Selangor, Malaysia

Organic acids are commonly used in marinades for poultry and meat products because they exhibit antimicrobial activity. We investigated the effect of citric acid, lactic acid, acetic acid and hydrochloric acid on the survival of Salmonella on chicken. Two strains each of Salmonella Typhimurium and Salmonella Enteritidis were inoculated separately onto chicken meat. Inoculated chicken was treated with different concentrations of the four acid solutions and incubated at refrigeration temperature. The pH of the acid solutions was measured before and after incubation. Salmonella was enumerated before and after exposure to each acid solution and compared to a control without the presence of chicken. As expected the viable count of Salmonella decreased as the pH decreased. Of the four acids, acetic acid resulted in the fastest (p < 0.001) rate of reduction of Salmonella on chicken (slope of 8.8), followed by citric acid (slope of 5.69), lactic acid (slope of 5.26) and hydrochloric acid (slope of 3.65). Acetic acid effectively eliminated Salmonella on chicken at ~pH 3.8 (p < 0.001). Lactic acid and citric acid eliminated Salmonella on chicken at ~pH 2.5 and ~pH 2.9, respectively. Elimination of Salmonella by hydrochloric acid occurred at pH 1.2 (p < 0.05). The antimicrobial mode of action of acetic acid is therefore due to other factors, in addition to its acidic pH, since the elimination of Salmonella caused by acetic acid occurred at a higher pH when compared to that of hydrochloric acid. The ability of acetic acid to eliminate Salmonella on chicken meat at approximately pH 4 suggests it has potential for practical application in commercial marination.