The Effect of Salting on the Microbiology of Poultry Meat

Abstract

An investigation was carried out on the effect of salting on microbiology of chilled poultry meat, with particular emphasis on possible selective influence of salt on predominant spoilage organisms. A significant reduction in total aerobic counts at 4.5 and 20 C and Enterobacteriaceae counts on the skin surface of fresh broiler carcasses was achieved by salting; the mean log reductions per cm2 being 1.19, 1.32, and 1.35, respectively. The two major genera found on the carcasses at the time of spoilage at 4.5 C were Moraxella and Pseudomonas. The percentage of Moraxella Increased from 48 in untreated to 68% in salt-treated samples, while pigmented Pseudomonas decreased from 31 (untreated) to 12% (salt-treated) of the total isolates. The recovery of isolates of Pseudomonas and Moraxella, in mixed populations, from heart infusion broth containing NaCl concentrations from 0.09 (aw 0.990) to 5.22 M (aw 0.814) was studied in 4 h-periods at 4.5 and 20 C. After 1 h incubation, as NaCl concentration was increased, the numbers of Pseudomonas were increasingly reduced both at 4.5 and 20 C, whereas numbers of Moraxella remained almost unchanged. The reduction of Pseudomonas counts, even at low NaCl concentrations, persisted after 2 h and 4 h incubation. Some reduction in Moraxella counts became apparent only after 4 h. and in concentrations higher than about 4.0 M (ca. aw 0.85). It is concluded that the much higher salt tolerance of Moraxella as compared with that of Pseudomonas, accounts for the increase in the percentage of Moraxella in the bacterial population, as salt was added to the poultry meat.