Nilgün Öncül

Application of lactococcin BZ and enterocin KP against Listeria monocytogenes in milk as biopreservation agents

This study was performed to evaluate the effect of lactococcin BZ and enterocin KP against Listeria monocytogenes ATCC 7644 in skim (0.1%), half (1.5%), and full fat (3.0%) UHT milks. The milk samples were inoculated with L. monocytogenes at the level of approximately 2.60, 4.76, and 6.45 log CFU ml −1 , and then treated with various concentrations (400, 800, 1600, or 2500 AU ml −1 ) of lactococcin BZ, enterocin KP, or their combination (1:1). Lactococcin BZ at 400–2500 AU ml −1 level displayed strong antilisterial activity, and decreased the viable cell numbers of L. monocytogenes to an undetectable level in all types of milk samples during the entire storage periods at 4 °C or 20 °C. Enterocin KP also had a high antilisterial effect, but it decreased as both the fat content of milk and inoculation amount of L. monocytogenes increased.

Determination of Some Physicochemical and Microbiological Properties of Rosehip Marmalades

In this study, some physicochemical and microbiological properties and antioxidant capacity of 30 rosehip marmalades produced in Tokat province by industrial or regional methods were determined. pH, water activity, viscosity, total dry content, total soluble solids, total ash, total sugar content, total ascorbic acid content and Hunter values (L*, a* and b*) were carried out to determine the physicochemical properties of samples and the means were 4.12, 0.881, 2501.6 cP, 56.12%, 56.86, 0.935%, 50.24 g/L, 173.43 mg/100g, 30.89, 10.90 and 15.11, respectively. The count of S. aureus, total and fecal coliform was not detected in any samples. The total phenolic content and TEAC were performed to investigate antioxidant capacity and the average values were 921.62 mg GAE/100 g and 66.93 µmol trolox/g.