Effect of high pressure processing on physicochemical and microbiological properties of marinated beef with reduced sodium content

High pressure processing (HPP) is one of the newer technologies that has shown great potential for manufacturing meat products with reduced sodium content. The aim of this study was to evaluate the effect of HPP applied at different levels in the inactivation of Listeria innocua and Enterococcus faecium inoculated in marinated beef (Longissimus lumborum) with reduced sodium content, as well as its influence on the physicochemical properties of the meat. Samples were inoculated with 106CFU/g of L. innocua and E. faecium, and marinated with solutions in different concentrations of NaCl (1 or 2%) and citric acid (1 or 2%) for 18h and treated with high pressure (300, 450 or 600MPa). Samples treated with 600MPa were also evaluated regarding physicochemical stability after 14days of refrigerated storage. Different marinating solutions were not sufficient to reduce initial microbial loads in the non-pressurized samples, but the combination with high pressure caused six log cycle reductions of both microorganisms. The treatment with 2% salt/2% citric acid was the most effective for each pressure considered for both bacteria. No significant changes were observed in the water activity of the samples, however samples with higher concentration of citric acid showed lower (p<0.05) pH and lower (p<0.05) lipid oxidation after 14days of storage under refrigeration. Only samples treated with 600MPa showed an increase (p<0.05) in hardness. The results showed that HPP was able to process a safe meat product with reduced sodium concentration.The result from this study shows the benefits of using HPP as an alternative meat processing technology to develop a meat product with reduce sodium content. Meat processed by this method have better nutritional quality and extended shelf life as compared to conventional processing. The step taken in this study will aid the meat processing industry for the development of microbiologically safe meat product with low sodium content by the application of high pressure processing.