Evaluation of ultraviolet radiation (UV-C) and high hydrostatic pressure (HHP) on total bacterial count in minas frescal cheese

Consumer demand for healthy, natural and additive-free food, with greater stability during storage has encouraged companies and food industries to work with alternative technologies to ensure microbiological safety, without negatively affecting nutritional components. Minas frescal cheese (MFC) is a dairy food that has very high humidity, because of this, and other intrinsic factors, hygiene during production, transport and storage is critical for the microbiological safety of this product. The use of new processing technologies can influence MFC's microbiological stability, increasing its shelf time and control the potential microbiological hazards in this product. Among the emerging technologies used to dairy processing, ultraviolet radiation (UV-C) and high hydrostatic pressure (HHP) present relevance. This study aimed to evaluate the inactivation of total aerobic bacteria (TAB) present in the natural microbiota of MFC submitted to different doses of technological treatments UV-C (0.097 to 0.392 J.cm-2.s-1) and HHP (100 to 400 MPa, for 10 min), employing an experimental design of the Central Composite Rotatable Design type. The lack of fit the model was not statistically significant (p = 0.070), indicating its adequacy. The value of R2 equal to 0.79 indicated the fit of the model to the data. Only HHP treatment had a significant individual effect on TAB inactivation in MFC. The highest mean decimal reduction of TAB was 0.51 ± 0.28 log CFU/g observed in MFC submitted to UV-C dose of 0.152 J.cm-2.s-1 and HHP pressure of 400 MPa. The combination of UV-C and HHP are promising technologies with potential action to reduce microorganisms in MFC.