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/cm(2)) were cooked in microwave either packed or unpacked at two internal temperatures (50 and 70 degrees C). When the samples were cooked up to the internal temperature of 50 degrees C, the reductions were 1.82 log cfu/cm(2) (29%) for packed and 0.69 log cfu/cm(2) (11%) for unpacked whiting. For the same cooking temperature, the reductions were 2.39 (33%) and 0.73 log cfu/cm(2) (10%) for packed and unpacked salmon, respectively. When the internal temperature was 70 degrees C, the reductions in S. Enteritidis counts were 2.89 (45%) and 3.90 cfu/cm(2) (54%) unpacked whiting and salmon, respectively. However, the reductions were higher in packed samples of both fish cooked to 70 degrees C internal temperature than that of unpacked samples and counts of the pathogen were below the detectable level (<1.00 log cfu/cm(2)). 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 degrees C.