1. Resistance of thermophilic spore formers isolated from milk and whey products towards cleaning-in-place conditions: Influence of pH, temperature and milk residues.
- Author
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Wedel C, Wenning M, Dettling A, Scherer S, and Hinrichs J
- Subjects
- Animals, Colony Count, Microbial, Dairying, Drug Resistance, Bacterial, Hydrogen-Ion Concentration, Kinetics, Powders, Whey Proteins metabolism, Acids pharmacology, Alkalies pharmacology, Microbial Viability drug effects, Milk microbiology, Spores, Bacterial drug effects, Temperature
- Abstract
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 HNO
3, 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., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2019
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