This research paper aimed to examine the antibacterial activity of lactoferrin (LF) as a potential natural alternative in the dairy sector, by measuring its minimum inhibitory concentration (MIC) against a number of common food-borne pathogens as well as Pseudomonas aeruginosa, one of the major dairy product spoiling microorganisms. Additionally, a viability experiment was applied to laboratory-manufactured set yoghurt to assess its impact on the activity of starter culture, sensory properties and STEC survivability. The findings demonstrated that LF exhibited significant antimicrobial activity, particularly against E. coli and S. typhimurium with MIC values of 0.0001 and 0.01 mg/ml, respectively. However, P. aeruginosa and B. cereus were quite resistant to LF requiring higher concentrations for MIC (2.5 mg/ml). By the third day of storage, LF at 0.0001 and 0.001 mg/ml significantly reduced the survivability of Shiga toxin-producing E. coli STEC by 70 and 91.6%, respectively, in the lab-manufactured yoghurt. Furthermore, LF enhanced the sensory properties of fortified yoghurt with a statistically significant difference in comparison to the control yoghurt group. There was no interference with the activity of the starter culture throughout the manufacturing process and the storage period. In conclusion, the potent antimicrobial effect of LF opens a new avenue for the dairy industry's potential applications of LF as a natural preservative without negatively influencing the sensory properties and starter culture activity of fermented products.
Keywords: Antibacterial activity; Shiga toxin producing E. coli; lactoferrin; natural preservative alternative; sensory properties.