The Effect of Thawing and Storage Temperature on the Microbial Quality of Commercial Frozen Ready Meals and Experimental Reduced Salt Frozen Ready Meals

摘要

The effect of thawing at 4oC or ambient temperature (~20oC) on the indigenous microflora of commercial regular salt (0.6-1.3% w/w) frozen ready meals was investigated. In a separate trial, the microbial quality of regular salt frozen ready meals was compared with reformulated reduced salt (0.2-0.54%, w/w) counterparts stored at 4oC, 10oC or ambient temperature over 8 days. All samples were analysed for psychrophilic, mesophilic, thermophilic and sporeforming bacteria, Pseudomonas , Staphylococcus and for the presence of Listeria species. During storage, psychrophiles, mesophiles, coliforms, Pseudomonas , sporeformers and Listeria were detected in the commercial regular salt ready meals while mesophiles, thermophiles, coliforms and Pseudomonas were detected in the reduced salt counterparts. Levels of mesophilic bacteria ranged from ~3-4 log 10 in commercial regular salt meals and ~2-5 log 10 in experimental lower salt meals. Overall, a substantial reduction in salt content (50 – 66%) did not appear to adversely impact on the microbial quality of the reduced salt meals.