Suppression of propanoic acid, acetic acid and 3-methylbutanoic acid production by other volatiles in a Swiss cheese curd slurry system

The effect of the addition of 5–100 ppm 2,3-butanedione, butanoic acid, methyl mercaptan, ethyl butanoate, diethyl sulfide, 3-methylbutanoic acid, acetaldehyde and ethanol on production of propanoic acid, acetic acid and 3-methylbutanoic acid in a Swiss cheese slurry system was investigated. Enumeration of propionic acid bacteria (PAB) was done to monitor the microbial count in the systems. A Swiss cheese slurry system was used to simulate cheese manufacturing based on accelerated ripening for a 6-day incubation period. The headspace concentrations of propanoic acid, acetic acid and 3-methylbutanoic acid were significantly decreased by the addition of 2,3-butanedione, butanoic acid, and methyl mercaptan, but were generally unaffected by ethyl butanoate, diethyl sulfide, 3-methylbutanoic acid, acetaldehyde and ethanol. Microbial enumeration also showed that there was a significant reduction of PAB in slurry systems with 100 ppm 2,3-butanedione, butanoic acid, and methyl mercaptan.