Organic acids effect on spoilage psyhrotrophic microflora during the shelf life of bovine carcasses

Abstract

The aim of this research was to assess the residual antimicrobial effect of 3% lactic and acetic acid solutions on the load and configuration of psychrotrophs at bovine carcasses. During October 2016 and December 2016, 18 bovine meat samples were collected from a comercial slaughterhouse in Transylvania. Collected samples were sprayed with 3% acetic acid and lactic acid solutions by spraying on the surface of meat samples. Each sample was divided into three sub-samples, from which two were treated with 3% organic acids solutions and one was the control sample. Experimental design were carried out over a 14- day period with microbial analyses at day 0, 1, 5, 9, 14. After spraying with organic acid solutions, the samples were kept at 2-4°C for 24 hours, and the following microbiological determinations were carried out: total load of psychrotrophic germs and isolation of microorganisms from the genera Pseudomonas, Aeromonas, Yersinia and Enterobacteriaceae family. The initial psychrotrophs load of the control sample presented during the experiment an ascendant evolution, from 3.23±0.2 log CFU/cm2 to 6.21 ± 0.25 log CFU/cm2, maximum admitted level being exceeded on day 10. After application of 3% acetic acid solution, the total load of psychrotrophic germs decreases to 2.05 ± 0.15 log CFU/cm2, afterwards showing a constant increase until the last day of the experiment to 4.89 ± 0.21 log CFU/cm2. The most sensitive psychrotrophic bacteria regarding the decontamination effect of lactic and acetic acid were Aeromonas spp. Lactic and acetic acid solution shown an obvious residual antimicrobial effect during the shelf life of bovine carcasses, when compared with control (p<0.05). Although acetic acid has more pronounced residual antimicrobial effect, we recommend using 3% lactic acid because it is a natural metabolite of muscle tissue and does not induce organoleptic changes in meat compared to acetic acid. The use of these methods of decontamination of carcasses should be considered as complementary measures to ensure hygienic quality and meat, and must be integrated within HACCP systems.