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Shiga-like toxin-producing Escherichia coli (STEC) is an important source of food contamination that presents risks to human health. Several industrial food processes eliminate this microorganism; however, these processes can alter the characteristics of the product. Alternative methods of preservation have been identified as an option to control these foodborne pathogens. The purpose of this study was to evaluate the action of bacteriocins produced by Enterococcus durans MF5 in STEC cells. Cell-free supernatant (CFS) containing enterocins from the MF5 isolate was tested over different time points (6, 18, and 24 h). Enterocins present in the crude CFS showed inhibition against STEC at all time points. In the investigation of cell integrity, using propidium iodide and fluorescence microscopy, considerable cell death was observed within 6 h of the cells being in contact with the enterocins, which was also observed at the 18 and 24 h time points. These results showed that the enterocins produced by the MF5 isolate have potential use in the control of STEC.

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Enterocins carry out antimicrobial activity on several pathogenic and spoilage bacteria in food. The objective of this work was to evaluate the production of enterocins, using Enterococcus faecium, and their stability under different culture conditions. The isolate was incubated in ManRogosa Sharpe (MRS) medium with pHs 4.5, 5.0, 5.5, 6.0 and 6.5, and supplemented with lactose, mannose, mannitol, glycerol, tween 20, and tween 80. The optimum pH of production was between 6.0 and 6.5. The enterocin produced in mix (lactose 20, glycerol 20, tween20 5.0 g L -1 ) was more efficient. None pH tested interfered with the reduction of the action of the enterocins. The thermal stability varied according to the isolate as well as the supplementation used. Tween 20 and 80 with regards to the stability to different chemical products of both isolates, presented reduction of the action. It was observed that the supplement mix had higher adsorption and that the bactericidal effect was observed within 2 hours of incubation. The results indicated that the different culture conditions did not affected the antagonistic action of enterocin.

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The choice for a healthy diet that enhances quality of life has increased in recent years causing food manufacturers seek to meet consumer demand, differentiating products and services. Regular consumption of fermented foods like yogurt and frozen foods rich in antioxidants such as blueberries is recognized as beneficial to maintaining good health. This effect is attributed, in part, the lactic acid bacteria used in the preparation of frozen yogurt that has therapeutic properties and the presence of phenolic compounds present in blueberries, which counteract the effect of free radicals. Thus the aim of this study was to develop and characterize pulp added frozen yogurt blueberry and fresh powder. The yogurt made with frozens pulps were characterized and compared with a control formulation with added red dye Bordeaux. From the analyzes, it was concluded that the pulp of fresh blueberries showed levels of total phenolics and flavonoids in higher amounts in the pulp powder can be a viable alternative to coloring of in natura instead of artificial coloring.