Inhibitory substances:

·   Inhibitory substances: 

                             These originally present in the food or added purposely to prevent growth of micro organisms.

Freshly drawn milk – Lactenins, anticoliform factors.

Egg white – Lysozyme

Cran berries – Benzoic acid

Short chain fatly acids on animal skin cabbage and other brassicas, garlic, onions and

leeks.

Allicin – Garlic, onion, leeks.

Phytoalexins are produced by many plants in respone to microbial invasion.

Antifungal compound phaseolin produced in green beans

Eugenol – Allspice (pimento), cloves, cinnamon

Thymol – thyme and oregano

Cinnamic aldehyde – cinnamon and Cassia

Inclusion of cinnamon in raisin bread retards mould spoilage.

Humulones contained in the hop resin and isomers produced during processing, impart the characteristic bitterness of beer.

Oleuropein – The bitter principle of green olives have antimicrobial properties.

Lysozyme present in milk, egg is most active against gram positive bacteria.

Egg – Ovotransferrin, avidin ovolflaroprotein.

Milk – Lactoferrin

Ovoflavo protein and avidin in egg white which sequester biotin and riboflavin restricting

the growth of those bacteria.

Milk has capacity to generate antimicrobials in the presence of hydrogen peroxide. The

milk enzyme lactoperoxidase will catalyse the oxidation of thiocyanate by H2O2 to produce inter alia Hypo-thiocyanate. This can kill gram negative bacteria and inhibit gram positives.

Propionic acid produced by the propionic bacteria in a swiss cheese is inhibitory to molds.

Nisin produced by certain strains of Streptococcus lactis may be useful in inhibiting lactate fermenting, gas forming clostridia in curing cheese. Heating foods may result in the formation of inhibitory substances. 

Ex: Heating lipids may hasten auto oxidation and make them inhibitory.

Browning concentrated sugar syrups may result in the production of furfural and hydroxyl methyl furfural which are inhibitory to fermenting organisms