Bactericidal Mechanism Of GML,Ozone And IPL On Salmonella

Salmonella is a major zoonotic pathogen that has a high detection rate in the poultry processing sector and poses a serious health risk to humans.Chemical disinfectants containing chlorine and thermal sterilization methods are commonly used in industry to inactivate Salmonella,but these sterilization methods leave harmful chemicals behind or damage the properties of chicken,lowering the quality of the chicken and even posing a risk to human health.As a result,finding a safe,efficient,residue-free sterilizing procedure that does not compromise product quality is critical.In order to investigate the bactericidal effect and mechanism of the compound disinfectant of GML,IPL,and Ozone on Salmonella,it was applied to the chicken processing chain.（1）To enhance the bactericidal rate of Glycerol monolaurate for Salmonella,this reagent was combined with three disinfectants:lactic acid（LA）,cetylpyridinium chloride（CPC）,and trisodium phosphate（TSP）,which can present acid,neutral,and alkaline in solution.The results showed that the 1%GML and a complex disinfectant（0.5%GML-0.025%LA）could powerfully sterilize Salmonella.Their bactericidal rates respectively were able to achieve 99.92%and 98.29%with the vortex treatment,indicating that the vortex treatment could improve GML to destruct the outer membrane of Salmonella.During the simulation test of the soaking and rinse processing of chicken,for a short time（0 h）,the effect of 0.5%GML-0.025%LA compound was better and more suitable for instantaneous sterilization than others,while for a long time（4 h）,1%GML exhibited a better bactericidal effect,which indicated it to be more suitable for long-term bacteriostasis.The characterization of color and texture for chicken samples were determined using Colormeter Ci7600,TA.XT Plus and Hyper-spectral Imager,which demonstrated that all samples treated by these complex disinfectants were not significantly different.In conclusion,GML is a potential and superior disinfectant for the chicken process.（2）The bactericidal efficacy of IPL and Ozone on Salmonella in both in vitro and chicken was investigated in this study by the change of cell morphology and intracellular oxidoreductase of salmonella and chicken character.The findings revealed that IPL reduced salmonella concentration in vitro by 2.11 log CFU/m L and in chicken by 1.76 log CFU/m L at 0h,while Ozone treatment had no impact.The surface of salmonella treated with IPL was clearly damaged or even broken,but the surface of salmonella treated with Ozone had minimal change and less damage,according to SEM result.The color,texture,and surface spectrum of chicken revealed that IPL and Ozone treatment had no effect on the qualities of chicken.NADPH enzyme activity increased significantly after Salmonella was exposed to IPL,while GR activity decreased significantly,resulting in a large number of O^2-and ROS that could not be degraded,resulting in cell death.In response to external stimulation,H₂S is created in the cell,which encourages a large increase in Trx R,indicating that the stress mechanism involving non glutathione is activated to eliminate part of the ROS and let the cell to survive.In general,IPL has a superior bactericidal effect on salmonella in vitro and in chicken,and is suited for chicken processing due to its high efficiency,reduced processing time,and lack of food character harm.（3）Global transcriptomic analysis was used to investigate the survival mechanism of Salmonella ATCC 13076 treated by IPL.The expression of 793 genes was changed,with 498 genes up-regulated and 295 genes down-regulated.The main roles of these differentially expressed genes,according to go and KEGG enrichment data,are to regulate the production and metabolism of nucleic acids,proteins,and amino acids,as well as to stimulate response.Furthermore,IPL primarily disrupts Salmonella DNA integrity,causing DNA damage and breaks to inhibit bacterial growth.IPL can also harm Salmonella membrane proteins,resulting in cell content leakage,homeostasis disruption,and cell growth stagnation or death.In response to the IPL,firstly,Salmonella halted DNA replication,triggering the SOS emergency repair system and DNA double-strand break repair to repair the DNA at the damaged location.Secondly,Salmonella decreased the size of the porin to prevent content leakage while increasing polysaccharide transport and reducing other processes,and regulates the metabolism of various amino acids（such as arginine,proline,tyrosine,and others）to offer additional energy and nitrogen supplies for cell repair.Therefore,some cells can survive under the stimulation of IPL.According to the findings,both the GML compound disinfection and IPL are effective and safe sterilization procedures that can be used in the chicken processing chain.