Application of Different Sterilising Modes and the Effects on Processed Cheese Quality

Lazarkova Z., Buňka F., Buňkova L., Valasek P., Kracmar S., Hrabě J . (2010): Application of dif ferent sterilising modes and the effects on processed cheese quality . Czech J. Food Sci., 28: 168–176. The aim of the present work is to evaluate the impacts of four different sterilising modes (110°C 100 min, 115°C 32 min, 120°C 10 min, and 125°C 3.2 min – with a constant lethal effect on microorganisms) on some chemical (pH, total and bio-available lysine, and ammonia content), microbiological, and sensory (shade and acceptability) proper ties of processed cheese depending on the lactose additions (0.0–2.0% w/w). All sterilising modes used were sufficient to inactivate the microorganism groups observed (total number of microorganisms, colony forming units of yeasts and/or moulds, number of spore-forming microorganisms). The falling sterilisation temperature kept for an adequately prolonged period of time caused darkening of the processed cheese and a decline of their acceptability. Consequently, greater losses of lysine and ammonia content increase occurred when the sterilisation temperature decreased. Com pared to non-sterilised products, the smallest changes were detected in the cheese treated with temperatures 125°C for 3.2 min, and 120°C for 10 minutes. The decrease of the processed cheese quality was more apparent with the growing lactose concentration.