... mainly used for bread preservation, as it will not interrupt the leavening in bakery goods raised by yeast. The other salt of propionic acid, sodium propionate is employed chiefly in confectionery. Mechanisms of action The antimicrobial activity is related to amino acid uptake inhibition and growth inhibition in the cell membrane. Propionic acid carries out neutralization of the protonmotive force by shuttling undissociated molecules through the membrane. They are then dissociated on the inside of the membrane. Apart from that, it can work within a high pH range, which is the condition in most bakery goods owing to low dissociation constant. Moreover, they can combat against moulds and prevent ropiness caused by the action of Bacillus mesentericus. 3.Nisin It was found in "Swiss cheese". Properties It is a polypeptide antibiotic, produced by some 'Lactococcus lactis 'strains. The polypeptide consists of 34 amino acids. Although it is defined as an antibiotic, it ...

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