The function and mechanism of lactic acid bacteria in the reduction of toxic substances in food: a review

N-nitrosamines, heterocyclic amines, polycyclic aromatic hydrocarbons, biogenic amines, and acrylamide are widely distributed and some of the most toxic substances detected in foods. Hence, reduction of these substances has attracted worldwide attention. Lactic acid bacteria (LAB) inoculation has been found to be an effective way to reduce these toxic substances. In this paper, the reduction of toxic substances by LAB and its underlying mechanisms have been described through the review of recent studies. LAB aids this reduction via different mechanisms. First, it can directly decrease these harmful substances through adsorption or degradation. Peptidoglycans on the cell wall of LAB can bind to heterocyclic amines, acrylamide, and polycyclic aromatic hydrocarbons. Second, LAB can indirectly decrease the content of toxic substances by reducing their precursors. Third, antioxidant properties of LAB also contribute to the reduction in toxic substances. Finally, LAB can suppress the growth of amino acid decarboxylase-positive bacteria, thus reducing the accumulation of biogenic amines and N-nitrosamines. Therefore, LAB can contribute to the decrease in toxic substances in food and improve food safety. Further research on increasing the reduction efficiency of LAB and deciphering the mechanisms at a molecular level needs to be carried out to obtain the complete picture.