Does boiling milk make it last longer?

In this brief guide, we are going to answer the question “does boiling milk make it last longer” with an in-depth analysis of the effect of boiling on the shelf life of milk. Moreover, we are going to discuss the boiling point of milk and the tips to store milk properly.

So without much ado, let’s dive in and figure out more about it.

Does boiling milk make it last longer?

Yes. In order to sufficiently preserve milk quality and free it from pathogenic and most spoilage-causing microorganisms, milk must undergo heat treatments such as pasteurization and ultra-high temperature processing (UHT). (1)

The boiling process kills many bacteria present in the raw milk, thus prolonging the shelf life of the milk. Thus simply boiled milk lasts for about 2-3 days in the fridge in an air-tight container or bottle at or below 40°F (4.4°C). (2)

Many consumers do not like the flavor (referred to as cooked, boiled or cabbagey) that is associated with milk that has been too severely heat treated, such as UHT and sterilized milk.Therefore one approach is to use temperatures above 100°C for shorter times.

There is no doubt that temperatures in the range 115-120°C for 1-5 s are more effective than temperatures below 100°C for extending the shelf-life of refrigerated products.

Direct processes, either injection or infusion processes, offer an alternative solution to this problem and milks processed by this method at 138°C for 2-4 s  are known as ultra pasteurized in the USA. 

Heat treatments can greatly extend milk shelf-life. Such milks have been successfully stored for as long as 150 days at 30°C with only very low levels of spoilage. (3)

What is pasteurization?

Pasteurization is the process in which we heat the milk to about 72°C for at least 15 seconds or 63° C for about 30 minutes and afterward, cool the milk rapidly. 

It is also known as the high-temperature short-time (HTST) pasteurization. This process almost kills 99% of all the bacteria present in the milk. Thus, it saves the milk from spoilage and prolongs its shelf life. (1, 3)

What is UHT?

Ultra-high-temperature pasteurization is the process in which milk is heated to about 138°C to 150° C for 1-2 seconds and is cooled down rapidly afterward. 

Packed and sealed in sterile containers, the UHT milk lasts for about a long time (6 months if unopened) when stored in the fridge at or below 40°F. Thus UHT milk has a longer shelf life than raw milk or simply pasteurized milk.(1, 3)

At what temperature does milk spoil?

Milk if stored above 40°F will start to develop the signs of spoilage like off-smell, off-flavor, and curdled texture after some time. Milk lasts for about 2 hours if kept at room temperature but if the temperature is more than 90°F, then the milk lasts for only an hour.

Milk is a highly perishable commodity and has a lot of macro and micronutrients present in it. Moreover, the milk has a lot of water present in its formulation so if it is kept out for more than 2 hours, bacteria and other microbes will find their way into the milk and will spoil it. (4)

What is the optimum temperature to store milk in the fridge?

Pasteurized milk should be kept at 3-4°C (37-39°F) in the refrigerator. It is recommended to avoid storing the milk carton in the refrigerator door to prevent temperature fluctuations. 

When milk is frozen, its shelf life can be extended for up to 6 months, but it is best consumed within a month to maintain quality. Frozen milk may have a slightly grainy texture and separated fat, making it ideal for cooking or for use in smoothies and shakes. 

The refrigerator temperature should be maintained between 38°F (3°C) and 40°F (4°C) for optimal milk storage. After use, it is important to promptly return the milk carton to the refrigerator to maintain its freshness.(5)

What factors affect milk shelf life?

The storage conditions and temperatures to which milk is exposed play a vital role in determining its safety and freshness. 

Mishandling, improper storage temperatures, or inadequate storage durations can lead to contamination of milk with harmful microorganisms, posing significant risks to public health.

In regions with tropical climates, where transportation, storage, or retail facilities may lack sufficient refrigeration capabilities, bacteria cells have the opportunity to recover after being exposed to heat, thanks to favorable temperatures. 

As a result, there is an increased risk of recontamination of processed milk, even after undergoing heat treatment, primarily due to poor hygiene practices.

The number of bacteria present in milk, and consequently its overall shelf life, is greatly influenced by both the storage temperatures and the storage methods employed. 

Therefore, it is crucial to adhere to proper storage practices to ensure that milk remains safe and suitable for consumption. (5)

Conclusion

In this brief guide, we answered the question “does boiling milk make it last longer” with an in-depth analysis of the effect of boiling on the shelf life of milk. Moreover, we discussed the boiling point of milk and the tips to store milk properly.

Citations

  1. Lu, M., & Wang, N. S.  Spoilage of Milk and Dairy Products. The Microbiological Quality of Food, 151–178. 2017.
  2. Buehler, A. J., Martin, N. H., Boor, K. J., & Wiedmann, M.  Psychrotolerant spore-former growth characterization for the development of a dairy spoilage predictive model. Journal of Dairy Science, 101(8), 6964–6981. 2018.
  3. Lewis, M. Improving pasteurized and extended shelf-life milk. Improving the Safety and Quality of Milk, 277–301. 2010.
  4. U.S. Department of Agriculture. https://ask.usda.gov/ Website. Washington, DC. What is the “2 Hour Rule” with leaving food out?.
  5. Adda Bjarnadottir, Kelli McGrane, How Long Is Milk Good for After the Expiration Date? Them. Healthline Media LLC. 2020

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