Abstract
Cooling and freezing temperatures are considered two of the most efficient methods to delay or inhibit growth of microorganisms in chicken meat and meat products during transport or storage. It can help improve the safety and prolong shelf life of such products. The purpose of this study was to evaluate chicken meat quality under freezing and different cooling temperatures. The data showed that the values of the chemical and microbial indicators were affected by freezing and cooling temperatures. Total viable bacteria, Pseudomonas and fecal Streptococcus counts (log(10) CFU/g) in chicken meat at day 0 were 5.5, 4.2 and 3.8, respectively. These counts (log(10) CFU/g) increased after 3 days of storage at 4+/-1 degrees C to 6.0, 5.9 and 5.5, respectively, also they increased to 7.1, 7.4 and 5.6, respectively, when chicken meat was stored at 7+/-1 degrees C. Total viable count, Pseudomonas and fecal Streptococcus count were significantly decreased when chicken meat was stored at -10 degrees C, -18 degrees C and -18 degrees C in vacuum package. The results indicated that the staphylococci and Staphylococcus aureus counts were higher in winter season compared to summer season. Total viable bacteria, Pseudomonas and fecal Streptococcus and coliform counts were lower in winter samples. Salmonella was positive in both winter and summer season samples. At day 0 the TBARS in chicken meat samples was 0.10+/-0.03 mg malonaldehyde/kg. After 3 days of storage at 4 degrees C, 7 degrees C, -10 degrees C and -18 degrees C, the TBARS increased to 0.22+/-0.05, 0.28+/-0.03, 0.18+/-0.05 and 0.15+/-0.03 mg malonaldehyde/kg, respectively. The TBARS in the chicken meats that were packaged under vacuum and kept at 4 degrees C and -18 degrees C for six days were 0.23+/-0.01 and 0.20+/-0.07 mg malonaldehyde/kg, respectively. Free fatty acids in chicken meat increased from 0.75+/-0.11% at day 0 to 0.93+/-0.15%, 0.87+/-0.21%, 0.90+/-0.28%, 1.1+/-0.15%, 1.7+/-0.15% and 0.87+/-0.13% in samples preserved at -10 degrees C, -18 degrees C, -18 degrees C with vacuum package, 4 degrees C, 7 degrees C and 4 degrees C with vacuum package, respectively.