Effect of ultraviolet radiation on the reduction of major food spoilage molds and sensory quality of the surface of dried filefish (Stephanolepis cirrhifer) fillets

Abstract

Aspergillus niger, Penicillium citrinum, and Cladosporium cladosporioides are the primary spoilage molds of dried fishery food products. This study investigated the effects of different doses of ultraviolet (UV) light (260nm) on the reduction of A. niger, P. citrinum, and C. cladosporioides on experimentally contaminated dried filefish (Stephanolepis cirrhifer) fillet surfaces and the effect on the quality of the fillets. All three strains counts were significantly (p<0.05) reduced by the stepwise increase of UV dosage on the surface of dried filefish fillets. The overall reduction of the spoilage molds by UV treatment ranged from 1 to 2 log10CFU/g. Specifically, the average reduction of A. niger, C. cladosporioides, and P. citrinum with 180–1,800mWs/cm2 of UV were 1.32 (95.21%), 1.42 (96.20%), and 1.41 (96.11%) log10CFU/g, respectively. However, the largest reduction for P. citrinum was 2.18 (99.34%) log10CFU/g following the maximum UV dose of 1,800mWs/cm2. Although the differences in Hunter color (L, a, b) and sensory parameters (color, texture, and appearance) of the fillet were not significant (p>0.05) between the nontreated (control) and UV-treated fillets, the flavor and overall acceptability significantly (p<0.05) decreased with the stepwise increase of UV, except for the fillets treated with 600mWs/cm2 of UV. This study suggested that 600mWs/cm2 of UV at 260nm could potentially be used for the inactivation of A. niger, P. citrinum, and C. cladosporioides in dried fishery food products such as dried filefish fillets without any concomitant changes in the color or sensory qualities of the fillets.