Inhibition of spore germination and/or bacterial growth can be promoted by ensuring the use of a cheese starter culture with high acid producing activity, by avoiding inadequate pressing of the curd which may result in weak areas in the curd or unexpelled whey pockets which could create conditions for the formation of gas holes, and by the use of compounds (e.g. lysozyme, nisin), although not universally permitted, to inhibit spore germination and/or bacterial growth.

Lysozyme 

Lysozyme hydrolyses peptidoglycan, a component of the bacterial cell wall, and promotes cell lysis. Some spores are quite resistant to lysozyme, while others are relatively easily inhibited. When added to cheesemaking milk and retained in the curd at 90-99%, the dose added to cheesemaking milk should be sufficient to inhibit butyric acid fermentation without inhibiting acidification by lactic acid bacteria and, where appropriate, propionic acid fermentation.

The use of lysozyme is limited to cases where spore counts are not excessive (e.g. are not excessive (e.g. < 500 spores/L), as small numbers of clostridia can survive can survive lysozyme and the higher doses required for high spore required for high spore counts can have a negative effect on the desirable lactic and propionic acid fermentations in the cheese. in the cheese. Lysozyme is often used in combination with with bactofugation and as an alternative to nitrate addition. Where nitrate addition is permitted, lysozyme can be used in combination to to reduce the dose of nitrate required.

Late gas blowing is a defect in certain hard and semihard varieties caused by the anaerobic catabolism of lactate to butyrate, CO2, and H2 by Clostridium tyrobutyricum.Hydrogen, in particular, has low solubility in the aqueous phase of cheese and so remains a gas leading to blowing in the cheese. This problem can be overcome by good hygiene, addition of NaNO3 or lysozyme, or by the physical removal of the spores by bactofugation or microfiltration.

Nisin

Nisin (an antibacterial peptide containing 34 amino acid residues) is a broad-spectrum bacteriocin effective againstmany Gram-positive organisms, including Clostridium spp. It may be used to prevent spoilage of processed cheeses which are produced from blends of natural cheeses and other ingredients and heated to ∼80°C. This heat treatment does not inactivate spores and when processed cheeses are stored at up to ambient temperature and with a suitable pH and aw, germination of the spores and growth of vegetative cells can occur, leading to butyric acid fermentation and gas blowing. Long chain polyphosphates have also been shown to inhibit the growth of Cl. tyrobutyricum in processed cheese spreads.

Addition of Nisin in the case of natural cheese manufacture, is more problematic as added Nisin is lost in whey and is also inhibitory toward lactic acid bacteria. The ability of adjunct bacteriocin-producing Lactobacillus cultures to prevent late blowing in brine-salted cheeses has been evaluated in recent years. It is necessary that these cultures do not inhibit starter cultures during cheese manufacture and should reach sufficient numbers after cheese manufacture to produce levels of bacteriocin that are inhibitory to the germination of spores. Also, these bacteriocin-producing cultures should not have a deleterious effect on cheese flavor during ripening.