A comparative study of the antimicrobial properties of nisin and natamycin in pasteurized liquid egg white and increasing its shelf life

This study aims to compare the antimicrobial properties of nisin and natamycin in pasteurized liquid egg whites. After breaking and processing the eggs and performing operations such as filtration and homogenization, the egg white liquid undergoes pasteurization at 56-57 °C for 10 minutes with a flow rate of 1800 m3/s. Following pasteurization, the liquid is mixed with 0.08% and 0.1% solutions of nisin and natamycin in packaging tanks. Microbial tests are conducted at 0, 7, 14, and 30 days of storage. Based on the results, the antimicrobial effect of both natural preservatives nisin and natamycin in the microbial tests of total count, coliform, mold, and yeast have a significant difference at the probability level of 5%. In the total count test, 0.1% nisin on the seventh day exhibits the lowest total count (1.71 log CFU/gr), while the control sample on the 30th day shows the highest (4/49 log CFU/gr). For natamycin, 0.1% on the seventh day and 0.08% on the seventh day have the lowest counts (2.63 log CFU/gr and 2.67 log CFU/gr) respectively, and the control sample on the 30th day has the highest (4.5 log CFU/gr). No microorganism growth is observed in samples containing nisin and natamycin for coliform, mold, yeast, Escherichia coli, Staphylococcus aureus, and salmonella tests. Nisin demonstrates a more intense reduction in total count compared to natamycin, indicating superior antimicrobial properties and increased shelf life over time.