Why is milk preserved

Hurty was far from the first to rant about the sorry quality of milk. But there were other factors besides risky strains of bacteria that made 19th century milk untrustworthy. The worst of these were the many tricks that dairymen used to increase their profits. Far too often, not only in Indiana but nationwide, dairy producers thinned milk with water sometimes containing a little gelatin , and recolored the resulting bluish-gray liquid with dyes, chalk, or plaster dust. They also faked the look of rich cream by using a yellowish layer of pureed calf brains.

Finally, if the milk was threatening to sour, dairymen added formaldehyde, an embalming compound long used by funeral parlors, to stop the decomposition, also relying on its slightly sweet taste to improve the flavor.

Today, public health scientists worry more about pathogens such as E. The heating of a liquid to to degrees Fahrenheit for about 20 minutes to kill pathogenic bacteria was first reported by the French microbiologist Louis Pasteur in the s. It was more than 20 years later that the German chemist Franz von Soxhlet would propose the same treatment for milk.

In , the Harvard microbiologist Theobald Smith — known for his discovery of Salmonella — also argued for this, after showing that pasteurization could kill some of the most stubborn pathogens in milk, such as the bovine tubercle bacillus.

But pasteurization would not become standard procedure in the United States until the s, and even American doctors resisted the idea. SlideShare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy. See our Privacy Policy and User Agreement for details.

A vivid description of all the preservation methods of milk and milk products is present in the slides. Very useful for Microbiology, Dairy technology students. The SlideShare family just got bigger. Home Explore Login Signup. Successfully reported this slideshow. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads.

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Cheese is healthy! How is cheese best stored? How much fat does cheese contain? How is curd cheese manufactured? Maintain a balanced diet with curd cheese.

The versatile use of curd cheese. Site notice German version. Homepage Products Site notice German version.