Sensitivity to organic acids in vitro and in situ of Salmonella spp. and Escherichia coli isolated from fresh pork sausages

Abstract

The production of fresh pork sausages inoculated with different multi-resistant bacterial strains, isolated from sausage commercially purchased from Brazil, was conducted to evaluate microbial inhibition by lactic acid. The isolates were identi- fied through 16S rDNA region sequencing and the bacteria with antimicrobial multi-resistance profiles were selected. The minimum bactericidal concentration was determined using lactic and acetic acids. Samples were contaminated by Salmonella Typhi, Salmonella Typhimurium, Salmonella Paratyphi, Escherichia coli and high counts of aerobic mesophilic bacteria. Antibiotic resistance was detected in 21 of the 27 analyzed isolates (six Salmonella spp. and 21 E. coli ). In the minimum bactericidal concentration test, lactic acid was more effective than acetic acid in the reduction of the bacterial population. The food matrix inoculated with two bacterial strains ( E. coli, Salmonella spp.) was treated with lactic acid at the concentrations of 1.5 and 4.0 M and showed no significant effect on the bacterial population.