Assessment of surface bacteria contaminations and sensory quality of selected vegetable fruits exposed to pulsed X-ray irradiation

Abstract

This study assessed the impact of pulsed X-ray irradiation on the bacteria contaminations and sensory quality of carrot and tomato. Fifty (50) kg each of carrot and tomatoes were collected into sterile sample polythene bags asceptically and were transported to the Food microbiology laboratory of the Ibrahim Badamasi Babangida University, Lapai for analysis. Bacterilogical quality assessment of the vegetable fruits were investigated using standard techniques. Carrot and tomato were exposed to different doses of 42, 50, 60, 67, 71, 75, 80, 85, and 90kv irradiation and non irradiated samples were analyzed microbiologically using pour plate technique. Odour, texture, color and general acceptibility of irradiated and non irradiated samples were analyzed by 20 trained panelies for sensory evaluation using 7 point hedonic scale. Different bacteria isolates from the surface of the carrot and tomatoes samples were observed culturally and microscopically. The result showed that carrot samples exposed to doses of 42,50, 67, 71, 75, 80 and 85kv and 90kv completely free of bacteria while tomato samples exposed to doses of 42, 50, 60, 67, 71, 75, 80, 85 and 90kv led to complete elimination of microorganisms present in the samples. Bacterial reduction rate of the exposed samples were directly propotional to the voltage and time exposed. There was gradual reduction in sensory profile of carrot within the voltage range of 5.0-3.5v and exposure rate of 42kv and 90kv. There was also a gradual reduction in sensory profile of tomato at the voltage range of 3.7-3.5v within the exposure rate of 42kv and 90kv respectively. The pulse x-ray is an effective non thermal treatment for vegetable fruits which could also preserve the sensory quality, however further studies are recomended to perfect this novel approach of food preservations.