EVALUATION OF THE EFFICACY OF ?-POLYLYSINE AGAINST NUTRITIONAL MICROBES IN YOGURT

Dina N. Ali* and Huda Elsayed

ABSTRACT

Being a natural antibacterial cationic peptide, ε-polylysine (ε-PL) is applied as a food preservative, however, the mechanism through which it acts against some food pathogens in yogurt has not been elucidated. This study focused on the inhibitory effect of ε-PL at different concentrations (0.005, 0.015 and 0.025%) against S.aureus, L.monocytogenes and E.coli inoculated in laboratory made yogurt. The most active functional groups were detected in ε-PL using Fourier-transform infrared spectroscopy (FTIR). The peptide could inhibit all the above mentioned pathogens two days after inoculation during refrigerated storage at 0.025%. Sensory properties was evaluated and it was revealed that ε-PL was the most preferred preservative by consumers with respect to taste, color, appearance and overall acceptability. As green consumerism is becoming more popular, there is a growing demand for natural preservatives. This study provides basic theories and methods for the application of ε‐PL against food-borne pathogens, as well as scientific guidelines for consumers and producers in the agricultural sector. The results obtained may promote the utilization of ε‐PL in the food industry, reduce the use of chemical preservatives and increase food safety.

Keywords: S.aureus; L.monocytogenes; E.coli; FTIR; consumer; sensory evaluation.