The potential for carbon dioxide formation during ripening of acid curd cheese

Inspired by recent reports on high concentrations of carbon dioxide in the atmosphere of ripening chambers used in acid curd cheese production, small-scale experiments were performed to systematically investigate sources of CO₂ formation. In a closed system with a ratio of cheese mass to air volume close to that in industrial scale, up to approximately 16% (v/v) CO₂ were observed within 3 d of maturation at 24 °C. Without addition of ripening salts (CaCO₃, NaHCO₃) the initial carbon dioxide formation was delayed, but maximum CO₂ levels were still much higher than admissible workplace concentrations. Control experiments with quarg, which was pasteurized for yeast inactivation, revealed that growth and activity of yeasts has to be considered as the most important source for carbon dioxide formation. The results of the study strongly point on the necessity of preventive measures for ensuring the safety of employees.