Resistance of thermophilic spore formers isolated from milk and whey products towards cleaning-in-place conditions: Influence of pH, temperature and milk residues.
The occurrence of thermophilic spore formers in dairy powders is a major concern for producers worldwide. This study aims to investigate the resistance of thermophilic endospores towards cleaning solutions typically used for cleaning-in-place in dairy manufacturing plants. From eleven tested strains, all were able to survive an alkaline treatment (NaOH) at 65 °C for 10 min (0.5%), whereas at concentrations of 2% eight strains withstood the treatment. Acid solutions were more sporicidal. At 0.5% of HNO3, only three strains survived the treatment. Milk impurities reduced the inactivation effect of the NaOH solutions towards thermophilic spore formers. For two selected strains, a detailed kinetic inactivation in NaOH and HNO3 solutions at different temperatures was performed and non-log-linear inactivation curves were observed. This study highlights the risk of reusing cleaning solutions in dairies.
['Wedel|Carolin|C|', 'Wenning|Mareike|M|', 'Dettling|Anna|A|', 'Scherer|Siegfried|S|', 'Hinrichs|Jörg|J|']
D000143:Acids D000468:Alkalies D000818:Animals D015169:Colony Count, Microbial D003612:Dairying D024881:Drug Resistance, Bacterial D006863:Hydrogen-Ion Concentration D007700:Kinetics D050296:Microbial Viability D008892:Milk D011208:Powders D013171:Spores, Bacterial D013696:Temperature D000067816:Whey Proteins
Thermophilic spore formers Cleaning-in-place Anoxybacillus flavithermus Milk powder processing