The Effects of Pre-processing Sanitation and Modified Atmosphere Packaging on Microbial Growth in Bulk Packs of Atlantic salmon (Salmo salar) fillets Fera R Dewi1,2, Shane M Powell2, Roger A Stanley2
1 Research Centre for Marine and Fisheries Product Processing and Biotechnology, Jakarta, 10260, Indonesia
2 Tasmanian Institute of Agriculture (TIA), University of Tasmania, Launceston, Tasmania, 7250, Australia.
Abstract
This research was to extend the shelf-life of fresh Atlantic salmon fillets when packaged in a bulk food service MAP trays with low gas to product volume ratios. When head-on-gutted (HOG) Atlantic salmon were just washed in Neutral Electrolyzed Water (NEW) sanitizer prior to filleting, the microbial load on the skin of HOGs treated at 20 ppm and 100 ppm chlorine equivalents decreased by 3.5 log CFU/cm2 down to 2.0 and 1.5 log CFU/cm2, respectively. Further trials washed the HOGs with 100 ppm of NEW. They were then filleted then packed in modified atmosphere packaging (MAP) at different product gas to product (G/P) ratios (0.4:1, 1:1 and 2:1) and stored at 0 C or 4 C up to 20 days. The combinations of sanitation pre-processing and high G/P ratio were most effective for maintaining the microbial count to 4.5 log CFU/g when stored at 0 C compared to a microbial count of 7.2 log CFU/g for the unwashed fillets after 20 days under 4 C storage. Other variable combinations were between these levels. A combination of improved pre-processing sanitation and a low temperature can, therefore, raise the hurdles for microbial growth to extend the shelf-life of bulk packed fresh salmon fillet MAP packed in the lower G/P ratios inherent to bulk fillets packed at high densities for storage efficiency.
