Mold growth, inhibitory effect

The most effective range for optimal microbial inhibition with sulfites is a pH of 2.5 to 3. It has been found that from 2 to 4 times greater concentrations of S02 are needed to inhibit the growth of microorganisms at a pH of 3.5 than at a pH of 2.5. It also has been demonstrated that, at a pH of 7, S02 has little if any effect on yeasts and molds, even at concentrations up to 1000 ppm. The inhibitory effects against bacteria are also considerably less when pH rises above 3.5. Some researchers believe that at higher pH levels, penetration of cell walls is much more difficult. 

Inhibitory Effect of Natamycin on Mold Growth and Toxin Production of ochraceus NRRL 3174, cyclopium NRRL 1888 and patulum NRRL 989... 

However, while some reports have indeed described the nature of the active LAB metabolites, the great majority of them have only described the inhibitory effect on mold growth. Taking the research one step further toward the effect of these active compounds on toxin production by the molds is critical. This would help in understanding the complex interactions between different metabolites that result in the antifungal effect and possible antimycotoxigenic activity of LAB. 

Kamal, M., Motohiro, T., Itakura, T. (1986) Inhibitory effect of salmine sulfate on the growth of molds. Bull. Jap. Soc. Sci. Fish. 52, 1061. 

It has a powerful inhibitory effect on bacterial and mold growth when present in concentrations above about 20%, is the most important gas. Earlier studies showed that COj inhibits growth of some anaerobic and facultative species, indicating that the effect is due to more than just the exclusion of oxygen. High concentrations of the gas may lead to discoloration and a sharp acid taste in some foods, because carbonic acid is produced by dissolution of CO in the water contained in the food. Afiuther problem consequent upon the solubility of the gas in both fatty and aqueous phases in the food is that of pack collapse, which is countered by adding a suitable gas. 

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