Performance of two alternative methods for Listeria detection throughout Serro Minas cheese ripening

ABSTRACT The ability of pathogens to survive cheese ripening is a food-security concern. Therefore, this study aimed to evaluate the performance of two alternative methods of analysis of Listeria during the ripening of artisanal Minas cheese. These methods were tested and compared with the conventional method: Lateral Flow System™, in cheeses produced on laboratory scale using raw milk collected from different farms and inoculated with Listeria innocua; and VIDAS®-LMO, in cheese samples collected from different manufacturers in Serro, Minas Gerais, Brazil. These samples were also characterized in terms of lactic acid bacteria, coliforms and physical-chemical analysis. In the inoculated samples, L. innocua was detected by Lateral Flow System™ method with 33% false-negative and 68% accuracy results. L. innocua was only detected in the inoculated samples by the conventional method at 60-days of cheese ripening. L. monocytogenes was not detected by the conventional and the VIDAS®-LMO methods in cheese samples collected from different manufacturers, which impairs evaluating the performance of this alternative method. We concluded that the conventional method provided a better recovery of L. innocua throughout cheese ripening, being able to detect L. innocua at 60-day, aging period which is required by the current legislation.

Efeito do processamento sobre as características físico-químicas de queijos artesanais produzidos na região do Serro, MG / Effect of processing on the physicochemical characteristics of artisanal cheeses produced in the region of Serro, MG

O presente estudo surgiu a partir da necessidade de caracterização do Queijo Minas Artesanal a fim de padronizar a tecnologia nas regiões tradicionais do Estado de Minas Gerais. Foram avaliados os efeitos dos diferentes processos de fabricação de três queijarias da Região do Serro sobre suas características físico-químicas. Conclui-se que há diferenças na composição dos queijos e, algumas delas são devidas às variações das etapas de fabricação. Sugere-se um estudo mais detalhado das etapas de fabricação, a fim de padronizar os queijos artesanais produzidos na região do Serro, melhorando o padrão e a qualidade dos mesmos.