Abstract
Lactoferrin is a natural component that is used as a food additive to inhibit the growth of pathogenic microorganisms. This study was designed to evaluate the antibacterial effect of lactoferrin against E. coli O157:H7, S. aureus L. monocytogenes, and B. cereus inoculated in one of the most popular Egyptian soft cheese “Karish cheese”. The sensory properties including appearance, odor and flavor of the cheese, to which lactoferrin was added, were evaluated. The results of sensory evaluation revealed that the samples treated with the different concentrations of lactoferrin were generally acceptable and did not negatively affected its sensorial properties. Moreover, the samples treated with high concentration of lactoferrin were given high score. Antibacterial effect of 1%, 2% and 4% concentrations of bovine lactoferrin against the foodborne pathogens were tested in vitro using agar well diffusion test to determine the appropriate concentration to be applied in cheese. The results showed that lactoferrin 4% concentration was the most effective concentration against all the examined foodborne pathogens, E. coli O157:H7, S. aureus L. monocytogenes, and B. cereus. The antibacterial effect of 4% lactoferrin against the before mentioned foodborne pathogens in Karish cheese was investigated and it could inhibit them during the cold storage period. This study highlighted that lactoferrin improved sensory properties of Karish cheese experimentally inoculated with some food borne pathogens such as E. coli O157:H7, S. aureus L. monocytogenes, and B. cereus, in addition to extending its shelf life at cold storage. Therefore, the addition of lactoferrin to Karish could improve its microbiological safety.

Key words: Antibacterial effect, lactoferrin, foodborne pathogens, cheese