Screening Of Lactic Acid Bacteria With Antibacterial Activity And Its Application In Fermented Sausage

Fermented sausage is loved by people because of its special flavor and rich nutrition,but the safety of traditional fermented sausage products is difficult to ensure,and the addition of starter cultures with antibacterial function is expected to solve this problem.In this study,we obtained a strain of Lactiplantibacillus plantarum Z43,which is safe,has the ability to inhibit bacteria,grows well,and can tolerate salt,acid,and nitrite by screening lactic acid bacteria isolated from fermented meat in laboratory conservation.Its fermentation supernatant has the strongest antibacterial activity when the strain grows to 24 hours,has strong acid-base stability and thermal stability,and is sensitive to protease K and pepsin,indicating that its antibacterial substance may be bacteriocin.The whole-genome sequencing results showed that Lactiplantibacillus plantarum Z43 has gene sequences encoding bacteriocins,a secondary metabolite synthesis gene cluster encoding phytocyclin,and encoded a variety of fermentation enzyme lines(e.g.lipase,branched-chain amino acid transferase,α-acetyl lactate synthase,etc.)that are associated with carbohydrate and amino acid metabolism to produce flavor.The changes in quality and microbial community of sausages inoculated with Lactiplantibacillus plantarum Z43 during fermentation were studied.The results showed that the p H value of sausage decreased rapidly to 5.08±0.06 after the first day of fermentation,which could quickly inhibit the growth of pathogenic bacteria.As the fermentation proceeded,the color measurement and the texture of the sausage kept getting better.In the early stage of fermentation,the contents of 2,3-butanedione,acetoin,and ethyl acetate increased significantly.The contents of butyl acetate and ethyl 3-methyl butyrate increased significantly in the later stage of fermentation.The core strains of fermented sausage are Lactobacillaceae,Lactobacillus,Citrobacter,and Lactococcus.The relative abundance increased gradually during sausage fermentation.Pearson correlation analysis showed that Lactobacillus was positively correlated with the synthesis of acetic acid,butyl acetate,ethyl acetate,and limonene.The comparison of fermented sausages inoculated with different culture starters showed that group A(Lactiplantibacillus plantarum Z43)had the best sensory evaluation,with an L value of 64.4±1.53 and a* of 7.56±0.58 at the end of fermentation,and a better texture than group CK(not inoculated with fermenters),comparable to group B(Lactiplantibacillus plantarum b-2),and second only to group C(commercial fermenters).The volatile flavor compounds in group A mainly include 2,3-butanedione,acetoin,acetic acid,ethyl acetate,limonene,etc.,which were higher than those in group CK(acids,ketones,and esters),and higher than those in group C(ketones).At the genus level,lactic acid bacteria dominated in group A,more Pediococcus in group C,no obvious dominant genus in group CK,and the potentially pathogenic bacteria in group A were significantly less than others.The p H value of group A maintained below 5.2 during fermentation and storage,lactic acid bacteria count was above 8 lg CFU/g,and the TVBN value was always lower than that of other groups.In conclusion,compared with Lactiplantibacillus plantarum b-2,commercial starter,and blank group,the fermented sausages inoculated with Lactiplantibacillus plantarum Z43 has better quality and safety,which improved the overall product acceptance.