Reduction of Salmonella Enteritidis in Fish by Microwave Cooking

Abstract

The effect of microwave cooking on the survival of Salmonella Enteritidis was investigated. Inoculated whiting and salmon fillets (6-7 log cfu/cm2) were cooked in microwave either packed or unpacked at two internal temperatures (50 and 70°C). When the samples were cooked up to the internal temperature of 50°C, the reductions were 1.82 log cfu/cm2 (29%) for packed and 0.69 log cfu/cm2 (11%) for unpacked whiting. For the same cooking temperature, the reductions were 2.39 (33%) and 0.73 log cfu/ cm2 (10%) for packed and unpacked salmon, respectively. When the internal temperature was 70°C, the reductions in S. Enteritidis counts were 2.89 (45%) and 3.90 cfu/cm2 (54%) unpacked whiting and salmon, respectively. However, the reductions were higher in packed samples of both fish cooked to 70C internal temperature than that of unpacked samples and counts of the pathogen were below the detectable level (<1.00 log cfu/cm2 ). These results suggested that packaging increased the S. Enteritidis reduction during microwave cooking and the reductions were higher in salmon than that of whiting. Microwave-cooking instructions must be included in the MW operating manuals. The foods must be cooked in microwave not lower than 360 W and 70°C.