Ingredients such as NaCl or organic acids can be used to control growth of microorganisms in food, as can natural antimicrobials such as natamycin, nisin and other bacteriocins, and various plant extracts including rosemary and thyme essential oils. The greatest efficacy against unwanted microorganisms can be ensured by utilizing synergistic effects of hurdles. Use of natural antimicrobials, both singly and in combination, can enhance the effects of other hurdles applied to control microorganisms.
A synergistic enhancement of nisin against Gram-positive bacteria such as Clositridium sp., Bacillus sp. and Listeria has been shown, when nisin is combined with other antimicrobials, organic acids or antioxidants. Proper use of antimicrobials in food can allow the reduction of other hurdles used to control microorganisms, thus resulting in food with superior sensory qualities.