Dean's mood was souring by the minute.
A bad instructor at a fitness club may not guide a practitioner properly, resulting in injury and forever souring the experience.
The lactic acid bacillus, always present in unboiled milk (to which the souring of milk is due), is easily destroyed by heat; but the bacillus mesentericus, often found in it, forms spores, which are not destroyed by ordinary boiling, and germinate when the milk is kept at a moderately warm temperature, producing a brisk fermentation whereby a large volume of gas is liberated.
Leave the milk on the skin 20 to 30 minutes and rinse gently away to prevent souring.
Without further purification it is also used for "souring" in bleaching, and in tin and lead soldering.
