APLICATION OF THE MICROBIOLOGICAL METHOD DEFT/APC AND DNA COMET ASSAY TO DETECT IONIZING RADIATION PROCESSING OF MINIMALLY PROCESSED VEGETABLES / Aplicação do método microbiológico DEFT/APC e do Teste do Cometa na detecção do tratamento com radiação ionizante de hortaliças minimamente processadas

AUTOR(ES)

Michel Mozeika Araújo

DATA DE PUBLICAÇÃO

2008

RESUMO

Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent healthy. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and inactivation of food-borne pathogens. Its combination with minimal processing could improve the safety and quality of MPV. Two different food irradiation detection methods, a biological, the DEFT/APC, and another biochemical, the DNA Comet Assay were applied to MPV in order to test its applicability to detect irradiation treatment. DEFT/APC is a microbiological screening method based on the use of the direct epifluorescent filter technique (DEFT) and the aerobic plate count (APC). DNA Comet Assay detects DNA damage due to ionizing radiation. Samples of lettuce, chard, watercress, dandelion, kale, chicory, spinach, cabbage from retail market were irradiated 0.5kGy and 1.0kGy using a 60Co facility. Irradiation treatment guaranteed at least 2 log cycle reduction for aerobic and psychrotroph microorganisms. In general, with increasing radiation doses, DEFT counts remained similar independent of irradiation processing while APC counts decreased gradually. The difference of the two counts gradually increased with dose increment in all samples. It could be suggested that a DEFT/APC difference over 2.0 log would be a criteria to judge if a MPV was treated by irradiation. DNA Comet Assay allowed distinguishing non-irradiated samples from irradiated ones, which showed different types of comets owing to DNA fragmentation. Both DEFT/APC method and DNA Comet Assay would be satisfactorily used as a screening method for indicating irradiation processing.

ASSUNTO(S)

irradiação de alimentos microbiologia teste do cometa irradiação de alimentos hortaliças minimamente processadas deft/apc hortaliças minimamente processadas teste do cometa deft/apc microbiologia detecção de alimentos irradiados detecção de alimentos irradiados

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