Assessment of the effect of marination with organic fruit vinegars on safety and quality of beef.

The aim of the present study was to determine the effects of organic fruit vinegars (blackberry, pomegranate, rosehip, and grape) used as marination liquids (MLs) on food-borne pathogens inoculated on beef, as well as on the quality characteristics (physical, chemical, microbiological and sensory properties) of beef during marination process at 4 °C for 24 h. In the first part of the study, meat samples separately inoculated with Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli O157:H7 (≅6 log CFU/mL) were marinated in four different MLs and the count of S. Typhimurium, L. monocytogenes and E. coli O157:H7 on samples decreased in the range of 1.040-1.225, 1.420-1.913 and 1.232-1.435 log CFU/g, respectively. Marination with rosehip vinegar (MLR) was determined as the most effective treatment against all pathogens. In the second part of the study, proximate composition, color parameters, cooking yield, marinate absorption, pH, texture profile, aerobic plate count and sensory properties of marinated meat samples were determined. The moisture content of the samples marinated with grape vinegar (MLG) (73.50%) was found lower than of the samples marinated with other formulations (in the range of 75.95-76.65%) (P < 0.05). Marination by various MLs resulted in significant differences between the L*, a* and b* values of meat samples (P < 0.05). The hardness value of the samples was decreased by marination with MLR (P < 0.05) and was determined as 25.70 N. There were no significant differences between the meat samples marinated with the four different MLs in terms of cooking yield, marinate absorption and pH (P > 0.05). Aerobic plate count was reduced in the range of 0.589-0.950 log CFU/g for 24 h marination (P > 0.05). The highest sensory evaluation scores in terms of flavor were determined in meat samples marinated with MLG (P > 0.05). Therefore, different fruit vinegars used as MLs improved the safety and quality of meat at different levels.

Assessment of technological characteristics of non-fat yoghurt manufactured with prebiotics and probiotic strains.

Microbiological, physicochemical, aroma and organic acid characteristics of non-fat yoghurt incorporated with ß-glucan and probiotic Lactobacillus plantarum strains (AB6-25, AC18-82 and AK4-11) combination as adjunct culture were investigated during a 21 day storage period at 4 °C. Four treatment yoghurts contained 0.25, 0.5, 1 and 1.5 % ß-glucan. Treatments also included probiotic combination and commercial culture. Treatments were compared with three controls produced containing commercial culture, commercial culture and probiotic combination, and commercial culture, Lactobacillus acidophilus and inulin. The results indicated that ß-glucan promote the viability of lactobacilli. However, the addition of ß-glucan (except 0.25 %) resulted in enhanced syneresis (P < 0.05). In general, the use of 0.25 % ß-glucan had no significant effect on pH, fat, protein and organic acid content of non-fat yoghurt. The results obtained from this research demonstrated that the use of 0.25 % ß-glucan has no adverse effect on the characteristics of non-fat yogurt produced with probiotic combination.