The Antimicrobial Efficacy Of Amaranth Crude Extract On Foodborne Pathogenic Bacteria And Potential Application In Cooked Meat

The food safety problem caused by foodborne pathogens is still one of the public's concerns.Meat products are part of foods that are susceptible to microbial contamination.In order to inhibit microbial contamination and prolong the shelf life of meat products,it has been studied that green and safe natural plant-derived bacteriostatic agents have been added to foods instead of chemical bacteriostatic agents.interest.The crude extract of leek has been initially proved to have a broad spectrum of antibacterial activity against some Gram-positive and Gram-negative bacteria,and its antibacterial mechanism has been rarely studied.Therefore,this subject will study the antibacterial effect of crude extract of amaranth on two foodborne pathogenic bacteria,explore its influence on the quality of cooked meat products,and provide theoretical support for the development of a new natural bacteriostatic agent.In this paper,Staphylococcus aureus ATCC 13565 and Cronobacter sakazakii ATCC 29544 were selected as test strains.For the study of antibacterial activity,this experiment uses the Oxford Cup method to determine the inhibition zone diameter of Staphylococcus aureus and Cronobacter sakazakii,respectively,The inhibition zone diameters of the two bacteria are 12.8 ± 0.5 mm and19.3 ± 0.6 mm when the concentration of crude extract of amaranth is 320 mg/m L.The minimum inhibitory concentration(MIC)of crude amaranth extract against Staphylococcus aureus and Cronobacter sakazakii was determined by agar dilution method to are 80 mg/m L and 20 mg/m L,respectively.The effect of crude extract of amaranth on the growth of two foodborne pathogens was detected by monitoring the absorbance of bacillus at OD600 nmfor 24 hours.The results showed that the antibacterial effect was enhanced with the increase of the concentration of crude extract of amaranth.For the study of antibacterial mechanism,the changes of cell membrane potential before and after treatment with crude extract of amaranth were determined.The membrane potential of treated cells was significantly increased(p<0.05),and the cells were depolarized,indicating cell membrane.Increased permeability and damage.By measuring the change of intracellular p H,the intracellular p H of the cells treated with the crude extract decreased significantly,which also indicated that the crude extract of amaranth caused damage to the cell membrane.The agarose gel electrophoresis was used to detect the damage of the DNA molecules of the cells,and the DNAbands of the cells treated with the crude extract of Amaranth were darkened,indicating that the crude extract of Amaranth passed through the damaged cell membrane and DNA molecules.Destruction of DNA molecule structure,inhibition of gene expression of substances that maintain cell activity.The results of SDS-page gel electrophoresis showed that the expression of bacterial cell protein was reduced by the crude extract of amaranth,and it was dose-and time-dependent.It further indicated that the cell membrane was severely damaged,leading to protein leakage,and it also indicated that the amaranth was thick.The extract inhibits genes involved in protein expression.Transmission electron microscopy can more intuitively show that the crude extract of amaranth deforms the cells,the cell membrane partially dissolves,the cell contents diffuse from the middle to the edge,partially leak,the nuclear region is dispersed,and the cells are destroyed.In this paper,crude extract was applied as a natural bacteriostatic agent to cooked pork,and the sterilized cooked pork was inoculated with Staphylococcus aureus.After treatment with crude extract,the number of colonies in cooked pork was significantly reduced(p<0.05).The p H of treated pork decreased significantly(p<0.05),the surface brightness value(L*)decreased significantly(p<0.05),and the redness value(a*)increased significantly(p<0.05),indicating that the crude extract of amaranth can be used as a natural bacteriostatic agent and pigment enhancer.Reducing microbial contamination,maintaining color stability and extending the shelf life of pork.In summary,the crude extract of leeks has antibacterial activity against Staphylococcus aureus and Cronobacter sakazakii,,and the antibacterial mechanism of crude extract of amaranth on the cells is: destroying the cell wall and cell membrane of the cells,resulting in Large molecular contents such as protein DNA leak.The crude extract of amaranth can reduce the number of colonies of Staphylococcus aureus on cooked pork,maintain the stability of pork color and prolong the shelf life of pork.Therefore,the crude extract of amaranth can be used as a high-quality natural bacteriostatic agent in the meat industry.