Evaluation of the use of radiation in microbiological control in tomato (Lycopersicon esculentum mill.) sold in the CEASA, Pernambuco

Tomato is one of the most consumed fruits in the world and also one of the agricultural products with most losses due to its high perishability. Nevertheless, there are only a few studies on the post-harvest life of tomatoes and therefore are still many undefined parameters related to the treatment and shelf life of different cultivars of that fruit. Its contamination occurs from the pre-to post-harvest crop. The diseases caused by food borne pathogenic microorganisms are a serious public health problem. The bacteria of the Enterobacteriaceae are responsible for large outbreaks of gastroenteritis in humans that may occur due to bacteria per se or by toxins produced by them. Thus, the development of technologies that make the food safe for human consumption has been growing in recent years. Preservation methods employ physical or chemical processes. Among such methods, irradiation is a preventive treatment for food safety. Irradiation can reduce post-harvest losses by killing insect pests in fruits, grains, spices, or by reducing food spoilage organisms by inhibiting the sprouting of plants and delaying the ripening of fruits. The objective of this research was to evaluate the potential of using different doses of gamma radiation to treat tomatoes sold in CEASA-PE and to perform the overall count of microorganisms in control and irradiated samples. The study used two lots containing 60 tomatoes such that 15 of them were used as the control group and 45 were irradiated with one of 3 different doses (1.0 kGy, 1.5 kGy and 2.0 kGy). For microbiological analysis, the tomatoes were sliced, and weighed (after removal of peel) in order to obtain samples weighing 25g. Each sample was added to an Erlenmeyer containing sterile water by agitation for 15 minutes. Aliquots of the washings were sown for exhaustion in sheep blood agar. After growth, colony counting was performed. The results revealed contamination in all tomato groups analyzed with the control groups exhibiting counts higher (105-6 CFU/g) than the limit recommended for commercialization (104 CFU/g) and significantly larger than those in irradiated samples. Also, only samples irradiated with 2 kGy had number of counts below such limit. Thus, it can be concluded that appropriate decontamination of tomatoes can be achieved by using a 2.0 kGy dose. (author)