Study On The Anti-microbial Properties Of Different Structure In Eggs

Research that focuses on the study and development of eggs has received a lot of attention, but few of them are about antimicrobial defense system.The current study is mainly about the antibacterial properties of proteins extracted from the eggs, while ignoring the antibacterial effect of the overall structure of eggs.In order to verify the anti-bacterial properties of the egg different structrue, the infection model were established to determine the average inhibition time of the eggs’ different external structure. The growth curve method was used to determinate the antibacterial properties of egg’s different internal structure, and the bacterial growth model were established. The growth curve and the oxford cup diffusion method were used to determine the antibacterial properties of egg white at different heating temperature. In addition, the antibacterial properties of duck egg white and hen egg white were compared, bacterial growth model in duck egg white were established. The main findings are as follows:1. The infection model of eggshell, shell membrane, eggshell and membrane the were established, inoculated1×102cfu/mL Salmonella enteritidis, Staphylococcus aureus, Escherichia coli. By continuous sampling and testing, the average inhibition time of different external structure were determined. The results showed that the eggshell’s average inhibition time of S. aureus was66h, E. coli is40.6h, S. enteritidis is34.8h. Eggshell membrane’s average inhibition time of S. aureus is27.6h, E. coli is24.6h,S. enteritidis is27h. The eggshell and membrane’s average inhibition time of S. aureus is75h, E. coli is60h, S. enteritidis is61.8h. Eggshell plays an important role in the anti-bacterial properties of eggs external structure, while the eggshell membrane has less inhibitory effect.2. The inhibition of S. enteritidis, S. aureus and E. coli by egg white, egg yolk and the whole liquid egg were studied by using growth curve method. They were inoculated with1×103fu/ml S. enteritidis, S. aureus. The three strains in egg white on are inhibited, while the egg yolk and whole egg is conducive to the growth of them. Egg white has the strongest inhibitory effect against S. aureus. In0-48h, the concentration of S. aureus in the egg white from the initial3.6log cfu/mL decreased to2.5log cfu/mL. Egg white has weak inhibition of S. enteritidis and E. coli. In0-48h, the concentration of S. enteritidis and E. coli were maintained between3.0-5.5log cfu/mL. In the whole liquid egg and egg yolk, the concentration of the three strains increased to9.0log cfu/mL after36h. According to the growth curve of the three strains in the egg white, egg yolk and the whole liquid egg, models were established, we compared two models to get the optimal model. This model is verified to be scientific, providing a helpful quantitative analysis for the research on the laws of bacterial growth in eggs.3. The growth curve and oxford cup method were used for the determination the antibacterial properties of egg white after different heat treatment to S. enteritidis, S. aureus, E. coli. The results show that egg white heated5min at25℃and37℃, has the strongest inhibitory effect on S. aureus. After45℃,55℃,65℃treatment, there is still some inhibition, but as the temperature increased the inhibition become weaker. Egg white heated at45℃for5min, has the strongest inhibitory effect on S. enteritidis, followed by37℃,25℃,55℃Egg white lost the inhibition of S. enteritidis but conducive to its growth after65℃treatment Egg white heated at37℃for5min, has the strongest inhibitory effect against E. coli. After25℃,45℃,55℃,65℃treatment, the inhibition of E. coli become weaker and weaker, especially after65℃treatment egg white lost inhibition.4. The inhibitory effect against S. enteritidis, S. aureus and E. coli were compared between duck egg white and hen egg white. The results show that the three strains was inhibited by duck egg white. It has strong inhibition of S. aureus, the concentration of S. aureus decreased by3.37log cfu/mL to2.62log cfu/mL. Compared with the antibacterial effect of hen egg white, the inhibition of S. aureus is weaker. It has similar inhibitory effect on S. enteritidis and E. coli. According to the growth curve of the three strains in the duck egg white, models were established. We compared two models to get the optimal model, and image analysis method were used to verify the validity of the model.