How fast does milk spoil?
In this brief guide, we are going to answer the question “how fast does milk spoil” with an in-depth analysis of the time it takes for milk to spoil and different ways to spot spoiled milk. Moreover, we are going to discuss the health implications of drinking spoiled milk.
So without much ado, let’s dive in and figure out more about it.
How fast does milk spoil?
Open milk, whether it be whole milk, skim milk, or reduced-fat milk stays for about 4 to 7 days before getting spoiled when stored in the fridge at or below 40 degrees Fahrenheit in an air-tight container or bottle.
On the other hand, the unopened whole milk lasts for about 5-7 days, reduced-fat and skim milk for 7 days while non-fat and lactose-free milk for 7-10 days past the printed date on it provided that it is stored properly in the fridge at or below 40 degrees Fahrenheit.
Last but not least, open milk lasts for about 2 hours before getting spoiled when left out at room temperature.
You should discard the milk that has been left in the open for more than 2 hours as bacterial growth takes place at a faster pace between the temperature of 40 and 140 degrees Fahrenheit.
It is worth mentioning that these figures are just the estimated shelf life of the milk and you should do a sensory evaluation of the milk to reach a final verdict on whether or not it is still suitable to consume.(1-3)
How to tell if that milk has gone bad?
There are a couple of indicators that point out spoiled milk. You should consider the appearance, texture, smell, and taste of the milk to give a final verdict of whether or not it has spoiled.
If you spot a mold or any other organic growth in your milk carton (it is a really rare phenomenon), then the best thing you can do is to get rid of this milk as it is an indication of spoiled milk.
If the milk is curdled or has lumps present in it, then it is an indication of spoiled milk and you should get rid of it.
If you smell something foul or sour while taking a sniff test then it is an indication that the milk has spoiled and the best thing to do is to discard it.
If the milk has passed the visual and smell test, then you can go ahead and taste it. If you notice a sour or slightly bitter taste after taking a little sip of milk then it is an indication that the milk has spoiled.
If microbes somehow found their way to your milk and have spoiled it then the best thing you should do is to discard it. (4)
What are the health implications of drinking spoiled milk?
If you have devoured milk that has spoiled, it can result in food poisoning that is characterized by nausea, vomiting, diarrhea, abdominal cramps, fever, weakness, headaches, and dehydration.
A mild food poisoning lasts for about a day or two while a more persistent case of food poisoning can last for about 10 days.
In case the symptoms worsen, or diarrhea and vomiting persist for more than 3 days you should seek medical help. (4, 5)
What factors affect milk shelf life?
The shelf life of milk is significantly influenced by the storage temperatures and methods employed. Improper hygienic handling, unsafe storage temperatures, and inadequate storage durations can lead to the entry of pathogenic microorganisms, posing a significant public health risk.
In regions with tropical climates, where chilling facilities may be lacking during transportation, storage, or retail, bacteria cells can recover after thermal injury due to favorable temperatures.
Consequently, there is an increased risk of recontamination of processed milk after heat treatment, primarily due to poor hygiene practices.
By implementing proper temperature control and adopting suitable storage practices, the growth of bacteria can be minimized, thus extending the milk’s shelf life. (6)
Other FAQs about Milk which you may be interested in.
In this brief guide, we answered the question “how fast does milk spoil” with an in-depth analysis of the time it takes for milk to spoil and different ways to spot spoiled milk. Moreover, we discussed the health implications of drinking spoiled milk.
- U.S. Department of Agriculture. https://ask.usda.gov/ Website. Washington, DC. What is the “2 Hour Rule” with leaving food out?.
- 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.
- Lacroix, M., Bon, C., Bos, C., Léonil, J., Benamouzig, R., Luengo, C., … Gaudichon, C. Ultra High Temperature Treatment, but Not Pasteurization, Affects the Postprandial Kinetics of Milk Proteins in Humans. The Journal of Nutrition, 138(12), 2342–2347. 2008.
- Lu, M., & Wang, N. S. Spoilage of Milk and Dairy Products. The Microbiological Quality of Food, 151–178. 2017.
- Adda Bjarnadottir, Kelli McGrane, How Long Is Milk Good for After the Expiration Date? Them. Healthline Media LLC. 2020
- Dortey, M. D., Aboagye, G., & Tuah, B. Effect of storage methods and duration of storage on the bacteriological quality of processed liquid milk post-opening. Scientific African, 10, e00555. 2020.