You’ve undoubtedly read the words “pasteurized” and “homogenized” on every gallon of milk you’ve ever purchased, but do you understand the process each of them represents? Both methods are vital to food safety and for preserving taste, but the two are very different. With the amount of dairy most people consume throughout their lives, it’s important to understand how it is made. In the simplest terms, homogenization is the breakdown of fat molecules in milk to resist separation. Pasteurization is the process of heating milk to kill bacteria. Typically, pasteurization is followed by homogenization.
The Pasteurization Process
Generally, the two primary goals of pasteurization in milk production are eliminating pathogens and prolonging shelf life.
Pasteurization begins by heating milk and then cooling it down rapidly, eliminating bacteria. The most common pasteurization method heats the milk to a temperature of at least 161.6 degrees Fahrenheit for 15 seconds. This method is called High-temperature Short-Time (HTST) pasteurization. Also known as flash pasteurization, this method will preserve milk’s freshness for up to three weeks.
Ultra-Heat Treatment (UHT) is an alternative method of pasteurization that heats milk to 280 degrees Fahrenheit for a minimum of two seconds. This treatment results in a significantly increased shelf life – up to nine months. Milk treated with UHT is considered “ultra-pasteurized.”
Pasteurization is named after the French microbiologist Louis Pasteur, who discovered he could deactivate unwanted microorganisms in wine through thermal processing. Pasteurization also renders the enzymes that are responsible for milk spoilage inactive. Nearly two centuries later, pasteurization is integral to the dairy, food processing, and food safety industries.
The Homogenization Process
Homogenization is an entirely distinct process that typically takes place after pasteurization. Homogenization aims to reduce the size of substances and allow small particles to be uniformly distributed and mix well throughout the milk. Without homogenization, milk fat molecules will rise and form a layer of cream. Proper homogenization will prevent the cream from forming by breaking the molecules down to a small enough size that they remain distributed evenly throughout the milk.
The most important thing for consumer sales and consumption is that homogenization increases milk’s shelf life, allowing large dairy operations to ship greater distances and sell to more retailers. Typically, homogenization is a purely mechanical process and does not involve the introduction of any additives. Homogenization benefits large-scale dairy farms by allowing them to blend milk from various herds.
The homogenization process is also essential when producing lower-fat and skim milk. It filters out the fat by changing the size of fat molecules and rearranging fat and protein molecules. The milk is passed through a small tube that reduces the size of fat molecules and maintains their dissolved state.
While some pasteurized milk products haven’t been homogenized – and homogenized milk that hasn’t been pasteurized – most milk product sold in U.S. supermarkets have undergone both processes.
Benefit of Purchasing Used Dairy Equipment
Dairy homogenizers and pasteurizers are common in both small and large-scale dairy production. Homogenizers, in particular, also have beneficial applications in several other industries, including pharmaceuticals, sanitation, and technology. The equipment typically offers a long lifespan with high-efficiency operation. Purchasing a used homogenizer can save a dairy significant money.
At Zwirner Equipment Company, all of our stainless steel used equipment is fully reconditioned and meets the original product’s specifications. Any dairy equipment purchased from our company can be tailored to your application.
Zwirner Equipment offers a variety of homogenizers in our inventory, including milk homogenizers, Gaulin homogenizers, Tetra Pak homogenizers, and more. Call today to learn more about purchasing used stainless-steel equipment, no matter where you are in the United States. We can deliver and install your equipment as well.
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