All about Dairy !
Did you know that 2.1 billion liters of milk are consumed every day all over the world? That’s enough to fill up 813 Olympic-sized swimming pools! With such large amounts of milk being consumed it is vital for milk producers to ensure that all milk is safe for human consumption. This is done through the process of pasteurization. Pasteurization is defined as using heat as a method to kill microorganisms present in fluid to ensure food safety for human consumption. There are many different types of pasteurization, however the three that are most commonly used are Batch or VAT, HTST and UHT.
The first type of pasteurization known as Batch or VAT pasteurization is most commonly done in VATs. This is a slow pasteurization process that requires the milk to be heated to a temperature of 145 degrees Fahrenheit and then held at that temperature for 30 minutes. Because of the length of time, this pasteurization method is not widely used, however some farmers and small milk processors still use this process for small batches around the world. The second type of pasteurization is HTST, which stands for high temperature, short time. It also is known as flash pasteurization. In this process, the milk is heated to 161 degrees Fahrenheit and held at that temperature for 15 seconds before it is blast chilled to kill microorganisms. This pasteurization method is being used in commercial dairy processing plants for faster and more efficient processing. Because of the speed of this pasteurization method, it is used in most milk production facilities. The majority of milk found in grocery stores is HTST pasteurized. The third type of pasteurization is UHT Pasteurization. UHT stands for Ultra High Temperature which means that the milk or cream is heated to 280°F-302oF for 1-2 seconds. UHT is another type of flash pasteurization. This temperature and time combination are much more lethal to bacteria, killing virtually all potential pathogens that are unsafe for human consumption. The milk is then packaged in sterile, hermetically-sealed (airtight) containers and can be stored without refrigeration for up to 90 days. After opening, spoilage times for UHT products are similar to those of conventionally pasteurized products. UHT is most often used for creams and specialty dairy products however is becoming more popular for milk.
Pasteurization is a crucial step in milk production for many reasons. It helps to eliminate pathogenic bacteria such as E-coli, Salmonella, and Listeria, reducing the risk of food borne illness. Because of this, pasteurization increases the safety of milk for consumption. In the US, milk-borne illness has been reduced by 30% due to pasteurization. Additionally, pasteurization increases the shelf life and quality of milk by destroying spoilage microorganisms and enzymes that contribute to reduction of milk quality overtime.
It is important to note that pasteurization does not significantly alter the nutritional qualities of milk. Studies have shown that the important nutrients in milk are not affected by heat. When it comes to vitamins and minerals, pasteurized milk is still an excellent source of calcium, riboflavin, vitamin A, and phosphorus and a good source of thiamine and vitamin B12. Important minerals like calcium and phosphorus are both absorbed from pasteurized milk just as well as from raw milk. Pasteurized milk is also fortified with vitamin D, which is essential for healthy bones, unlike raw milk which only contains a small amount of this important vitamin. One vitamin that’s levels are affected by pasteurization is riboflavin, or vitamin B2. While the quantity is decreased by pasteurization, pasteurized milk is still an important dietary source of this vitamin.
Research has shown that the high nutritive value of milk protein is not decreased through pasteurization. Levels of casein, the main protein present in milk are not altered in any way through pasteurization. In fact, proteins like lactalbumin and lactoglobulin become more digestible after pasteurization. Just a glass of milk has 8 grams of protein which helps build and repair muscle tissue.
Pasteurization is vital in milk production and ensures safe consumption of milk by destroying levels of pathogens that are unsafe for human consumption. Hence, the safest way to enjoy the health benefits of milk is through the process of pasteurization.
Manvi Lohia is a Penn State Dietetic Intern serving Penn State Extension Lebanon County. Penn State is an equal opportunity, affirmative action employer, and is committed to providing employment opportunities to minorities, women, veterans, individuals with disabilities, and other protected groups. Penn State Extension in Lebanon County is located at 2120 Cornwall Road, Suite 1, Lebanon, PA 17042, phone 717-270-4391, keg5293@psu.edu.
Sources:
Foster, Shannon, and Shannon Foster. “Health Benefits of Dairy | Milk Nutrition.” The Dairy Alliance, 28 Jan. 2019, thedairyalliance.com/health-benefits-of-dairy/.
Macdonald, Lauren E., et al. “A Systematic Review and Meta-Analysis of the Effects of Pasteurization on Milk Vitamins, and Evidence for Raw Milk Consumption and Other Health-Related Outcomes.” Journal of Food Protection, vol. 74, no. 11, 2011, pp. 1814–1832., doi:10.4315/0362-028x.jfp-10-269.
“Nutrients and Health Benefits.” Choose MyPlate, 26 June 2015, www.choosemyplate.gov/dairy-nutrients-health.