| Salmon are very popular with consumers,because of its rich nutrition,taste delicious.But the characteristics of easy corruption and not resistant to storage the serious influence it‘s storage and sales.Listeria monocytogenes is one of the most important food-borne pathogens,News has often reported to detect it in the salmon,Salmon can be eaten raw further increased the harm,Based on the Listeria monocytogenes and salmon as the research object,The response surface methodology was used to determine the optimal combination of antibacterial agents.The effects of the calculated combinations of antibacterial agents were evaluated on the preservation of raw salmon.The sensory changes,The bacterial count and The physical and chemical indicators content were measured to determine the changes in the quality of salmon during cold storage.The results were gotten as follows:1.the Antibacterial research about Lysozyme,glycine and sodium acetate respectively on three kinds of bacteria Staphylococcus aureus,Bacillus subtilis and Listeria monocytogenes.Through the determination of antibacterial rate to analyze the size of the bacteriostatic effect,First,measuring the antibacterial activity of different concentrations of bacteriostat on three kinds of bacteria,After the three kinds of antibacterial agents were mixed at the same concentration,applied to the inhibition of bacteria experiments.The results showed that with the increase of the concentration of antibacterial agent,the inhibition rate of bacteria to bacteria increased,and when the concentration reached a concentration,the inhibition rate began to flatten.The inhibitory rate of three kinds of antibacterial agents on the three kinds of bacteria was different.In general,the antibacterial effect of lysozyme was better than that of the other two kinds of antibacterial agents.When the three kinds of antibacterial agents were mixed,the inhibition rate of bacteria was improved,and the fence theory is an effective method to improve the compound bacteriostatic agent.2.Study on the Inhibitory Effect of Compound Bacteriostatic Agents on Response to Listeria monocytogenes by Response Surface Methodology.In order to be more effective inhibition of Listeria monocytogenes,the test by response to surface method,Mixed lysozyme,glycine,sodium acetate to study the antibacterial effect of the best antibacterial agent against Listeria monocytogenes,After the results were verified,and by measuring the inhibition rate,inhibition zone size to compare the antibacterial effect on Listeria monocytogenes of the same concentration with the Compound antibacterial agent and potassium sorbate,chitosan,ε-polylysine.The results showed that the optimal concentration of the mixture was as follows: lysozyme 0.6g/L,sodium acetate concentration 4.9g/L,glycine concentration 6.4g/L.The inhibitory rate of Listeria monocytogenes was 81%.Validation test antibacterial rate was 80% ± 0.23%,which was close to the predicted value of response surface,which indicated that the test results were reliable.The inhibitory rates of the Compound antibacterial agent,potassium sorbate,chitosan and ε-polylysine on Listeria monocytogenes were 81.9%,53.3%,69.7% and 43.5%.The size of the inhibition zone was 17.3 ± 0.3,8.6 ± 0.1 and 15.1 ± 0.2.7.7 ± 0.2 respectively.The results showed that the antibacterial effect of the combined antibacterial agent was much higher than that of the other three kinds of bacteriostats.3.Study on the Compound antibacterial agent’s Preservation of Salmon Meat with Listeria monocytogenes.Simulated infected with Listeria monocytogenes of salmon,The best concentration of the combination of antimicrobial agents used in this salmon preservation,And compared with the single antimicrobial component analysis,by measuring the total number of colonies,Listeria monocytogenes,pH,TBA and TVB-N value to compare the quality of salmon meat.The results showed that the growth of Listeria monocytogenes and other bacteria in the salmon was effectively inhibited,The changes of p H,TBA and TVB-N in the experimental group were small,According to the national standard,the total number of bacteria and TVB-N value and other physical and chemical indicators,The salmon group used Compound antibacterial agent than the blank group,extending the shelf life of 2 days.Compound antibacterial agent has a good antibacterial preservation effect,If the salmon is contaminated with a small amount of Listeria monocytogenes,it can eliminate the risk and control the risk of pollution.If the infection of a large number of Listeria monocytogenes can also prevent the salmon deterioration of salmon in a short time,greatly improve the safety of salmon.4.Research on preservation of compound bacteriostatic agent on the sensory quality of salmon tablet.Comparison the salmon with the Compound antibacterial agent and blank group,The sensory and quality changes of salmon fillets were evaluated by measuring sensory score,color difference ΔE,total number of colonies,pH value,TBA value and TVB-N value.The results showed that the sensory score of the salmon fillet was more slowly,the sensory evaluator refused to eat Blank group at the 6th day,compared with the experimental group 3d;Blank group color change is more obvious,in the 9d fast close to different colors.While the experimental group color difference ΔE is 10,At the same time,according to the total number of colonies,pH value,TBA value and TVB-N value,compared with GB,4℃ storage environment,the experimental group than the blank group to extend the shelf life of 3d. |
