Selection of nitrite-degrading and biogenic amine-degrading strains and its involved genes

Objectives:Accumulation of nitrite and biogenic amines(BAs)in fermented meat products is a matter of public health concern.The study aimed to screen nitrite-degrading and BA-degrading strains from sour porridges and sausages and bacon products in China.Materials and Methods:After screening out 12 strains,the degradation of nitrite,the degradation of BAs,the activities of nitrite-reducing enzymes,and the detection of genes involved in the BAs were assessed by spectrophotometry method with hydrochloric acid naphthalene ethylenediamine,high-performance liquid chromatography,GENMED kit,and polymerase chain reaction,respectively.Results:Pediococcus pentosaceus labelled M SZ12 and M GC 2,Lactobacillus plantarum labelled M SZ22,and Staphylococcus xylosus labelled Y CC 3 were selected.The activity of nitrite-reducing enzyme in M SZ22 was 2.663 units/mg.The degradation rate of total BAs of M SZ22 was 93.24%.The degradation rates of nitrite and BAs of M SZ12 were 86.49%and 37.87%,respectively.The activity of nitrite-reducing enzyme in M SZ12 was up to 1.962 units/mg.M GC 2 showed higher degradation rates of nitrite(89.19%)and Y CC 3 showed higher degradation rates of BAs(36.16%).The genes encoding the multicopper oxidases(suf I/D2EK17)were detected in the four strains,which also did not contain BAs(histidine decarboxylase(hdc),tyrosine decarboxylase(tdc),ornithine decarboxylase(odc),lysine decarboxylase(ldc))formation encoding genes.Conclusion:These four strains(M SZ12,M GC 2,M SZ22,and Y CC 3)are promising candidates to use as starter cultures for nitrite and BAs in fermented sausages.