How Long Can Milk Sit Out - [Answer] 2023: Blueberry farm

Article February 27, 2017

Everyone wants to keep their milk fresh as long as possible, but did you know that how long your milk sits out can impact that? In general, perishable foods like milk should not sit out of the refrigerator or cooler for longer than two hours. Cut that time down to an hour in the summer if the temperature reaches 90 degrees F.

While at the grocery store, pick up milk last so it stays as cool as possible. Refrigerate promptly after you get home. Ideally, milk should be stored in the refrigerator at 40 degrees F or below. Storing and serving milk at this temperature extends overall shelf-life and maximizes flavor. Store your milk in the coldest part of the refrigerator, not in the door where it will be exposed to outside air every time someone opens it. Milk is pasteurized to kill bacteria that could potentially cause health risks, Even so, it is not safe to leave pasteurized milk unrefrigerated for an extended time.

Following these simple guidelines can keep your milk as fresh as possible and avoid throwing out spoiled milk. For more information on food safety, visit FoodSafety.gov,

Contents

- 0.0.1 Can I drink milk that was left out overnight?

1 What happens if you leave milk out for hours?
- 1.1 How long does it take milk to go sour at room temperature?
2 How long does it take for milk to spoil?
3 What is the danger zone for milk?
- - 3.0.1 How long can milk be left out UK?
  - 3.0.2 How do you know if milk is spoiled?
- 3.1 What happens when milk is left at room temperature?
4 How do you keep milk fresh overnight without a refrigerator?
- - 4.0.1 Is milk still good if it gets warm?
5 Which milk takes the longest to spoil?
6 How long can cow milk sit out after being warmed?
- 6.1 Can milk be refrigerated after being heated?
7 How long can milk stay in the fridge without power?
- 7.1 Why are Europeans tolerant to milk?
  - 7.1.1 Why does milk last so long in Europe?
8 What happens when milk is left at room temperature?
- - 8.0.1 What happens if you leave milk out of the fridge all day?
9 How long can milk stay in the fridge without power?
10 How do you know if milk is spoiled?

Can I drink milk that was left out overnight?

Milk that has been left out overnight should not be consumed. According to food safety guidelines, milk should be refrigerated at or below 40°F (4°C) and should not be left out of the refrigerator for more than 2 hours. Leaving milk out overnight increases the risk of bacterial growth, which can make you sick.

What happens if you leave milk out for hours?

What Happens to Milk When It Is Left Out? – When milk is left unrefrigerated for an extended period, bacteria will begin to grow. The lactose in the milk becomes fermented by bacteria at room temperature and turns into lactic acid. A high amount of lactic acid in milk means a high amount of hydrogen ions, which causes a sour taste with a low pH value.

How long does it take milk to go sour at room temperature?

How long does it take for milk to spoil? – How long it takes for milk to spoil depends on what the temperature is as well as the conditions where it’s stored. Milk that is stored in the refrigerator should last until its expiration date, plus about a week to 10 days.

How long does it take for milk to spoil?

Milk can be refrigerated seven days ; buttermilk, about two weeks. Milk or buttermilk may be frozen for about three months. Sour cream is safe in the refrigerator about one to three weeks but doesn’t freeze well. For more information, you may call the FDA toll-free at 888-723-3366 or go to FDA’s website.

Can I drink milk left out for 4 hours?

Article February 27, 2017

Following these simple guidelines can keep your milk as fresh as possible and avoid throwing out spoiled milk. For more information on food safety, visit FoodSafety.gov,

Why is milk not refrigerated in Europe?

Why Don’t Europeans Refrigerate Their Milk? When you are having a bowl of cereal or some cookies, there is nothing better than a glass of milk. Of course, we all love to drink our milk when it is ice cold. You have probably never seen your mother pull a carton of milk out of the kitchen pantry before, right? Americans buy their milk out of the fridge and that’s where it stays once it comes home.

Why is that, though? Did you know that America actually differs from the usual norm in this regard? We are one of the only countries in the world that partake in the practice of putting milk in the fridge.
You may not have realized that Europeans actually buy and store their milk outside of the fridge.

The reason is a simple one: Europeans rely on a completely different pasteurization method. Canadian and American milk manufacturers utilize high-temperature, short-time pasteurization. This method is one of the best ways to kill off sizable amounts of bacteria. Photo: If milk is able to hang on for a long enough period of time, the bacteria are given a chance to return. The HTST method may work well enough for Americans, but the Europeans rely on the UHT method instead. The milk is exposed to much higher temperatures for just three seconds.

After being exposed to the temperatures, the milk is completely free of bacteria for at least six months.
Since the bacteria are all gone, the milk becomes more shelf-stable.
This milk also has a much different flavor because most of the sugar that American milk contains has been burnt off.
Companies have attempted to convince Americans to make the switch but there has been no luck so far.

We are bound and determined to continue placing our milk in the fridge. Different strokes for different folks, right? UHT milk is sold in the United States, though. These are the cartons that you see in children’s lunchboxes. Cold milk may be the only milk that we drink but there is a good reason for that.

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: Why Don’t Europeans Refrigerate Their Milk?

What happens if I drank milk left out for 2 hours?

How Safe is Day Old Milk? Source : Although most people have the good sense to keep milk refrigerated, how safe would it be to consume after being left out of the fridge? Well especially for children in particular drinking milk that has been left out of the fridge can be dangerous and result in food poisoning.

In order to prevent food poisoning from milk consumption it is vital to store milk correctly and keep it refrigerated.
The reason why drinking milk left out for too long can cause food poisoning is because this allows bacteria to multiply.
Bacteria like salmonella, listeria and E.coli are commonly found in most foods, but leaving food out of the fridge or freezer allows this bacteria to multiply at a rate that if consumed can cause illness.

People that are most at risk of developing food borne illness are pregnant women, children and the elderly because their immune systems may be compromised. The environmental factors that make milk more prone to developing bacteria include being left at room temperature which promotesbacterial multiplication and the longer the milk is left out of the fridge, the longer bacteria have to multiply and cause sickness if consumed.

Some of the things to look for to determine if milk has been contaminated is a sour smell and the fact that it has been left out of the fridge for an extended period of time.
Sometimes milk may not smell strongly or be discoloured but may be contaminated.
There is also the risk of milk curdling, which may occur due to bacteria or yeast being present in the milk.

Always check the milk before consuming it that it hasn’t curdled and ensure your children do so as well before drinking it. When you are not using milk it should be kept in the fridge because if it is left out all day, the chances are that it will spoil.

By refrigerating milk you ensure that harmful bacteria do not have the optimum temperature to multiply and cause sickness to anyone who consumes it.
Although refrigeration won’t keep bacteria from growing entirely, it will slow its growth.
Also do not drink past its expiry date.
When milk reaches its expiration date, this signals a time when the bacteria could re ach a high point and beyond this point they can cause illness.

Even if milk does not show signs of being spoiled or curdled, if it has been left out of the fridge for an hour that it is dangerous to consume. Milk left out longer than one hour could cause food poisoning, even if it does not smell or have curds or visible signs of contamination.

People who consume contaminated milk may suffer from an upset stomach, stomach cramping, diarrhea and fever.
Most often the symptoms will die down after a few days but in serious cases you may need to be hospitalised, especially if it affects children.
The diarrhea and vomiting will allow the child’s body to rid itself of the bacteria.

If the diarrhea lasts for more than 7 days and the person suffers from severe dehydration they should seek medical attention. : How Safe is Day Old Milk?

What is the danger zone for milk?

Safe Handling of Milk & Dairy Products Grade A milk is carefully produced, processed and packaged in order to protect the safety of the consumer. Grade A milk must be pasteurized to be sold by retailers in interstate commerce. Raw milk is usually pasteurized either by low temperature pasteurization in which the milk is heated to 145 °F or higher for at least 30 minutes, or by high temperature pasteurization in which the milk is heated to 161 °F or higher for at least 15 seconds and then quickly cooled.

Pasteurization destroys disease-causing bacteria and extends the shelf life of milk.
However, pasteurized milk can readily spoil and could cause foodborne illness if not properly protected and handled.
Maintaining the Safety of Milk: Refrigeration is the single most important factor in maintaining the safety of milk.

By law, Grade A milk must be maintained at a temperature of 45 °F or below. Bacteria in milk will grow minimally below 45 °F. However, temperatures well below 40 °F are necessary to protect the milk’s quality. It is critical that these temperatures be maintained through warehousing, distribution, delivery and storage.

The cooler refrigerated milk is kept, the longer it lasts and the safer it is.
As the product is allowed to warm, the bacteria grow more rapidly.
Properly refrigerated, milk can withstand about two weeks’ storage.
Infants, pregnant women, the elderly and the chronically ill (such as those undergoing cancer treatments and individuals with AIDS, diabetes or kidney disease) are most at risk from serious illness due to eating any unsafe food.

These individuals and those who care for them must be especially careful to handle milk safely. Fresh Fluid Milk: Fresh milk is categorized mainly by the amount of butterfat it contains. In November 1997, the FDA announced a new rule for milk labeling that helps consumers clarify the difference between 1- and 2-percent milk and reinforces the fact that skim milk is fat-free.

Under the new rule, 2-percent milk is renamed reduced fat; 1-percent milk is renamed low-fat; and skim milk is called fat-free or nonfat, although it may contain up to 0.5 grams of fat in a one cup serving.
Buying Fresh Fluid Milk: When selecting milk at the store, make sure it is properly displayed and pay close attention to the date on the label.

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All fresh fluid milks should be stored at temperatures below 40 °F and should not be stacked high in the display cases. If stored above 40 °F, milk will begin to develop signs of spoilage, including sour odor, off-flavor and curdled consistency. Remember that milk should be taken from the store and quickly placed in your refrigerator at home so that the temperature does not rise above 40 °F.

Once you have purchased milk and refrigerated it promptly, it should retain its fresh taste for one to five days beyond the “sell-by” date if kept at the proper temperature.
If it spoils before the date expires, this indicates it was not handled properly, and it should be returned to the store for a refund.

Storing Fresh Fluid Milk: Milk should not be left out at room temperature. Pour milk to be used into a serving container and return the original container to the refrigerator. Do not return unused milk that has been sitting out to its original container where it could contaminate the remaining milk.

Milk can be stored frozen at 0 °F for up to three months and will be safe to drink if it is thawed in the refrigerator, although it does not retain its smooth texture. Buttermilk: Originally, buttermilk was made as a by-product when making butter. Lactic acid bacteria are added to fresh, fluid pasteurized skim or part-skim milk to produce the thick, tangy buttermilk.

Buttermilk should be handled with the same precautions as regular fluid milk. Flavored Milk: Chocolate and other flavors – such as maple, strawberry and coffee – may be used for flavored milks. These milks are stored and used as fresh fluid milk.

How long can milk be left out UK?

by Joanne Lewsley | Medically reviewed by Gemma Caton, Specialist health visitor | September 2020 | Once you’ve made your baby’s feed, it’s best to use it as soon as possible. Leaving the milk out of the fridge for too long means that there’s a risk of harmful bacteria growing in it.

Should you make formula in advance? How to warm your baby’s bottle safely How to manage bottle-feeding on a long journey

Joanne Lewsley is a freelance copywriter and editor, and specialises in creating evidence-based parenting, health and lifestyle web content.

How do you know if milk is spoiled?

Milk can stay safe to consume for several days past the expiration date. Expiration dates on food and drink products relate to their quality rather than their safety. Drinking spoiled milk can make people unwell, but it is typically easy to tell when milk is bad.

There are many types of expiration dates on food and drink products, which can be confusing.
Producers of milk typically pasteurize it to kill off bacteria before selling it.
However, milk can still spoil and become unsafe for consumption.
In this article, we discuss how long milk can stay safe past the expiration date and explain what the different dates on food and drink labels mean.

There is no universal duration for how long milk is safe to consume after the expiration date. Different types of milk can remain fresh for varying lengths of time. Most milk that people purchase in the United States has undergone pasteurization, which involves heating the milk to kill harmful pathogens.

Although this makes the milk safer to consume, it does not mean that it is safe to leave milk out of the refrigerator for an extended time, particularly after opening it.
Some evidence suggests that pasteurized milk should remain fresh for 2–5 days after its sell-by date and 10–21 days in total.
There are different methods of pasteurization that can further extend the shelf life of milk.

For example, ultra-pasteurized milk can last about 30–90 days. This longer shelf life is due to a higher heating temperature during the processing. Manufacturers make aseptic, or ultra high temperature (UHT), milk by heating the milk with sterile equipment and filling it under aseptic conditions into specially designed containers that can extend the shelf life to more than 6 months.

The product itself may also be shelf stable, meaning that it does not require refrigeration until a person opens it.
It is advisable to avoid drinking raw, or unpasteurized, milk as it may contain harmful pathogens that can pose serious health risks.
Food and drink packaging in the U.S.
Typically contains at least one date, which can have different meanings.

These dates and their definitions can vary across labels and are not subject to uniform government regulations. According to the Food Safety and Inspection Service (FSIS), common dates on food and drinks labels include:

Use by: This is the last date the manufacturer recommends a consumer use the product by for peak quality. Best if used by: This date refers to the best flavor or quality of a product. Sell by: This date is a recommendation for how long a shop should display the product. Freeze by: This is the best date for freezing a product by to ensure the best quality.

These labels do not relate to food or drink quality. With proper handling, all products should remain safe after any of these dates. The FSIS does not require product dating, but voluntary use of dates must be truthful and follow the regulations, such as displaying both a day and month.

Infant formula is one exception that the FSIS does regulate because it can be unsafe after the use-by date. According to the Food and Drug Administration (FDA), people in the United States waste about one-third of their food each year, which is worth $161 billion. An estimated 20% of that waste is due to confusion over the meaning of food and drink labels.

The FDA is now working with other federal agencies to standardize the use of “best if used by” to indicate the date of optimal quality — except in the case of infant formula. The aim is to reduce the number of people throwing away products past their expiration dates that are still safe to eat.

Milk naturally contains bacteria that can spoil and cause diseases, such as Escherichia coli and Salmonella, Milk spoilage is the result of an overgrowth of bacteria that compromises the texture, flavor, and overall quality of milk. Often, psychrotrophic bacteria, which can grow under cold conditions, are responsible for milk spoilage.

The production of milk involves several stages that aim to kill off these bacteria to extend the shelf life. Milk production follows guidelines from the United States Department of Agriculture, Manufacturers will rear and milk dairy cows before storing the milk at 40°F or under and transporting it for testing and processing.

Pasteurization: Manufacturers heat the milk to kill bacteria before cooling it again. Homogenization: An atomizer disperses fat evenly through the milk and prevents it from floating to the top. Separation: A centrifuge spins the milk to separate the cream before recombining it with varying amounts of fat for different types of milk.

Several other stages may also be necessary, including further filtration or ultra high temperature treatment. Pasteurization kills off most but not all bacteria in milk, which can continue to grow after processing. After opening milk at home, new bacteria can enter it and grow, eventually causing the milk to spoil.

Expiration dates are poor indicators of whether milk is safe to consume.
The smell and appearance of the milk are clearer signs of how safe the milk is for consumption.
Spoiled milk will produce a sour smell as the bacteria produce lactic acid.
The smell will intensify after the milk becomes unsafe for consumption.

A yellowy color, crusts around the edges, and lumps in the milk also indicate that it is off. The processing of milk has a significant effect on how long it stays fresh and safe to consume. However, people can take steps at home to extend this duration.

putting milk in the fridge as soon as possibleputting the lid back on milk properly after usekeeping hot foods away from milk in the fridgeavoiding leaving milk out of the fridge for long periodskeeping the fridge temperature below 40°F

Drinking small quantities of spoiled milk can cause no symptoms or some minor symptoms, which will typically go away on their own. For example, it can cause stomach pain, nausea, diarrhea, or vomiting. Spoiled milk is unlikely to cause any long-term problems. However, drinking raw, unpasteurized milk is dangerous, Raw milk contains harmful pathogens that cause food poisoning, including :

Campylobacter C ryptosporidium E. coli Listeria Salmonella

Expiration dates relate to milk quality, not safety. Milk is generally safe to consume after the expiration date for at least a couple of days. People will typically be able to tell when milk is bad, as the smell and appearance indicate any spoilage. The type of processing that the milk undergoes can affect how long it will stay fresh.

What happens when milk is left at room temperature?

When the milk is left at room temperature, it results in oxidation reaction and growth of microorganisms following which themilk gets sour. oxidation rection take place when milk kept in roomtempreture during summer and it will become sour.

How do you keep milk fresh overnight without a refrigerator?

Insulated Lunch Containers – These containers come in many shapes and sizes, which makes finding one that fits your needs a snap. Bags with a gel lining keeps milk, yogurt, and other dairy foods cool throughout the day if you freeze them overnight. Or use a bag with a thermal lining that simply reflects the cool temperature of the food back into the bag. For best results, toss in an ice pack.

Is milk still good if it gets warm?

10/27/2015 – It’s a busy morning – getting ready, eating breakfast, fixing lunch, checking email, grabbing homework. Then you notice something out of place. A carton of milk is sitting on the counter. We’ve probably all had this happen and, at that point, three questions run through our minds: How long has the milk been out? Is it still safe? And who left it out? Our very own registered dietitian Sarah Downs stepped in to help us find some answers.

Okay, Sarah, bottom line: How long can milk be kept out of the refrigerator before it starts to spoil? Sarah Downs, RD: “Milk should never be left out at room temperature.
Refrigeration is the single most important factor in maintaining the safety of milk.
Milk should be stored at 40° F or below.
If stored above 40° F, milk will begin to develop signs of spoilage, including sour odor, off-flavor and curdled consistency.” What if you’re not sure how long the milk has been left out? Is there a way to tell if it’s still safe to use? Sarah Downs, RD: “When in doubt, throw it out.

The general rule of thumb is to discard any perishables that have been stored above the “Danger Zone” of 40° F for more than two hours, no matter what their appearance or odor (and never taste the food to try and determine whether it’s still safe).” What about ultra-pasteurized milk? Sarah Downs, RD: “Ultra-pasteurized milk is heated to 280° F for a minimum of two seconds.

This temperature and time combination is much more lethal to bacteria, killing virtually all of concern in milk.
Ultra-pasteurized milk is also packaged under near sterile conditions, which makes recontamination with spoilage bacteria unlikely and rare.
The average shelf-life of ultra-pasteurized milk products is 30 to 90 days when held under refrigeration, but only until the product is opened.

Then it should be consumed within seven to 10 days to avoid spoilage.” What’s different about the milk you see sitting at room temperature on the grocery store shelves? Sarah Downs, RD: “Shelf stable milk has been ultra-pasteurized (UHT) and is packaged in aseptic cartons.

Pack milk in a lunch box or cooler with an ice pack to ensure it stays cool.
Purchase shelf-safe milk (make sure it has the UHT label on the package too!). Also, remember that after this milk is opened it should be treated like regular milk and kept cool at 40° F or cooler.
It’s important to remember that opened milk, regardless of the type, should never be left in temperatures above 40° F for more than two hours.”

Although we may not figure out who was responsible for leaving the milk on the counter, these guidelines will help us stay safe and enjoy nutritious milk!

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Which milk takes the longest to spoil?

Why does organic milk last so much longer than regular milk? | Craig Baumrucker, professor of animal nutrition and physiology at Pennsylvania State University, pours out an answer: Credit: NIKHIL SWAMINATHAN Advertisement If you’ve ever shopped for milk, you’ve no doubt noticed what our questioner has: While regular milk expires within about a week or sooner, organic milk lasts much longer—as long as a month. So what is it about organic milk that makes it stay fresh so long? Actually, it turns out that it has nothing to do with the milk being organic.

All “organic” means is that the farm the milk comes from does not use antibiotics to fight infections in cows or, Organic milk lasts longer because producers use a different process to preserve it. According to the Northeast Organic Dairy Producers Alliance, the milk needs to stay fresh longer because organic products often have to travel farther to reach store shelves since it is not produced throughout the country.

The process that gives the milk a longer shelf life is called ultrahigh temperature (UHT) processing or treatment, in which milk is heated to 280 degrees Fahrenheit (138 degrees Celsius) for two to four seconds, killing any bacteria in it. Compare that to pasteurization, the standard preservation process.

There are two types of pasteurization: “low temperature, long time,” in which milk is heated to 145 degrees F (63 degrees C) for at least 30 minutes*, or the more common “high temperature, short time,” in which milk is heated to roughly 160 degrees F (71 degrees C) for at least 15 seconds.
The different temperatures hint at why UHT-treated milk lasts longer: Pasteurization doesn’t kill all bacteria in the milk, just enough so that you don’t get a disease with your milk mustache.

UHT, on the other hand, kills everything. Retailers typically give pasteurized milk an expiration date of four to six days. Ahead of that, however, was up to six days of processing and shipping, so total shelf life after pasteurization is probably up to two weeks.

Milk that undergoes UHT doesn’t need to be refrigerated and can sit on the shelf for up to six months. Regular milk can undergo UHT, too. The process is used for the room-temperature Parmalat milk found outside the refrigerator case and for most milk sold in Europe. So why isn’t all milk produced using UHT? One reason is that UHT-treated milk tastes different.

UHT sweetens the flavor of milk by burning some of its sugars (caramelization). A lot of Americans find this offensive—just as they are leery of buying nonrefrigerated milk. Europeans, however, don’t seem to mind. UHT also destroys some of the milk’s vitamin content—not a significant amount—and affects some proteins, making it,

There are, of course, lots of reasons people buy organic milk. But if it’s the long shelf life you’re after, I would recommend you buy nonorganic UHT milk and avoid being charged double. * Correction (6/6/08): This sentence originally said “milk is heated to 145 degrees F (63 degrees C) for at least 30 seconds.” (The error occurred during editing by the staff of ScientificAmerican.com and is not the fault of the expert.) Discover world-changing science.

Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners. : Why does organic milk last so much longer than regular milk?

How long can cow milk sit out after being warmed?

There is no nutritional reason to heat milk, but most babies prefer it lukewarm. Children usually begin drinking refrigerated drinks like milk, water and juice at 10 to 12 months, but if your child doesn’t like cold milk, you can continue warming it up. To reheat milk: Do not warm milk in a microwave oven. Microwaves heat unevenly, often at dangerously high temperatures.

Put the milk container in warm water for a few minutes until lukewarm. Shake gently. Disposable bags heat more quickly than plastic or glass bottles. To check the temperature, pour a few drops on the back of your hand or the inside of your wrist. The milk should be neither hot nor cold to the touch.

To thaw or reheat frozen breast milk:

Run cold water over the container, then gradually add hot water until the milk is lukewarm. Or put the milk in the refrigerator for 10 to 12 hours, then warm it in hot water. Stir, check the temperature and feed it to your baby.

Do not warm a bottle of milk in boiling water on the stove. All foods—both liquid and solid—lose some of their nutritional value when overheated. And babies have been accidentally burned with milk that was too hot or was heated in a microwave oven. Microwave ovens are also unsuitable because there is a risk that bags and glass bottles might explode.

Also breast milk loses some of its vitamins and antibodies when reheated in the microwave. Don’t leave reheated milk for more than two hours at room temperature. Throw it away if it is left out for this long because bacteria multiply quickly and could cause diarrhea. Antibodies : Substances made by the body to fight off disease.

Also called immunoglobulins.

Can milk be refrigerated after being heated?

Can Warmed Breast Milk Be Refrigerated Again? –

Yes, you can refrigerate warmed breast milk again as long as you make sure to use that milk within 2 hours of the first warming. So you have two hours once your breast milk first comes to room temperature or is warmed to feed it to your baby. Any breast milk not consumed after 2 hours should be discarded, even if it was put back in the fridge. Refrigeration slows bacteria growth so it may be better to keep unused breast milk in the fridge instead of room temperature during that 2 hour window.

How long can milk stay in the fridge without power?

Food Safety for Power Outages Refrigerated or frozen foods may not be safe to eat after the loss of power. Find out what you can do to keep food safe during a power outage, and when you need to throw away food that could make you sick.

Keep appliance thermometers in your refrigerator and freezer. The refrigerator should be at 40°F or below. The freezer should be at 0°F or below.

Prepare for emergencies or natural disasters:

Freeze containers of water and gel packs to help keep your food at 40°F or below. Have a cooler and frozen gel packs handy in case you have to remove your food from the refrigerator to keep it cold. Buy dry ice or block ice to keep your food cold in the refrigerator, if you think the power will be out for a long time.

Keep refrigerator and freezer doors closed. If the doors stay closed, food will stay safe for up to:

4 hours in a refrigerator.48 hours in a full freezer; 24 hours in a half-full freezer.

If the power has been out for 4 hours, and a cooler and ice are available, put refrigerated perishable foods in the cooler. To keep them at 40°F or below, add ice or a cold source like frozen gel packs.

Never taste food to determine if it is safe to eat. When in doubt, throw it out. Throw out perishable food in your refrigerator (meat, fish, cut fruits and vegetables, eggs, milk, and leftovers) after 4 hours without power or a cold source like dry ice. Throw out any food with an unusual odor, color, or texture, Check temperatures of food kept in coolers or your refrigerator with an added cold source. Throw out food above 40° If you have an appliance thermometer in your freezer, check to see if it is still at 40 °F or below.

You can safely refreeze or cook thawed frozen food that still contains ice crystals or is at 40 °F or below.

: Food Safety for Power Outages

Why are Europeans tolerant to milk?

Prehistoric people in Europe were consuming milk thousands of years before humans evolved the genetic trait allowing us to digest the milk sugar lactose as adults, finds a new study led by UCL and University of Bristol researchers. The research, published in Nature, mapped pre-historic patterns of milk use over the last 9,000 years, offering new insights into milk consumption and the evolution of lactose tolerance. Until now, it was widely assumed that lactose tolerance emerged because it allowed people to consume more milk and dairy products.

But this new research shows that famine and exposure to infectious disease best explain the evolution of our ability to consume milk and other non-fermented dairy products. Joint senior author Professor Mark Thomas (UCL Genetics, Evolution & Environment) said: “In late prehistory, as our ancestors started living in larger settlements, their health was increasingly impacted by poor sanitation and increased pathogen loads.

Under such conditions, even more so during times of famine, consuming milk would have increased death rates, particularly among those unable to digest the lactose in milk. Those who were able to digest lactose were thus more likely to pass on their genes enabling them to safely drink milk.” While most European adults today can drink milk without discomfort, two thirds of adults in the world today, and almost all adults 5,000 years ago, can face problems if they drink too much milk.

This is because milk contains lactose, and if we don’t digest this unique sugar, it will travel to our large intestine where it can cause cramps, diarrhoea, and flatulence; known as lactose intolerance. However, this new research suggests that in the UK today these effects are rare. Professor George Davey Smith, Director of the MRC Integrative Epidemiology Unit at the University of Bristol and a co-author of the study, said: “To digest lactose we need to produce the enzyme lactase in our gut.

Almost all babies produce lactase, but in the majority of people globally that production declines rapidly between weaning and adolescence. However, a genetic trait called lactase persistence has evolved multiple times over the last 10,000 years and spread in various milk-drinking populations in Europe, central and southern Asia, the Middle East and Africa.

Today, around one third of adults in the world are lactase persistent.” By mapping patterns of milk use over the last 9,000 years, probing the UK Biobank, and combining ancient DNA, radiocarbon, and archaeological data using new computer modelling techniques, the team were able to show that the lactase persistence genetic trait was not common until around 1,000 BC, nearly 4,000 years after it was first detected around 4,700–4,600 BC.

Professor Thomas added: “The lactase persistence genetic variant was pushed to high frequency by some sort of turbocharged natural selection. The problem is, such strong natural selection is hard to explain.” In order to establish how lactose persistence evolved, Professor Richard Evershed, the study’s lead from Bristol’s School of Chemistry, assembled an unprecedented database of nearly 7,000 organic animal fat residues from fragments of pottery from 554 archaeological sites to find out where and when people were consuming milk.

His findings showed milk was used extensively in European prehistory, dating from the earliest farming nearly 9,000 years ago, but increased and decreased in different regions at different times. To understand how this relates to the evolution of lactase persistence, the UCL team, led by Professor Thomas, assembled a database of the presence or absence of the lactase persistence genetic variant using published ancient DNA sequences from more than 1,700 prehistoric European and Asian individuals.

They first saw it after around 5,000 years ago. By 3,000 years ago it was at appreciable frequencies and is very common today. Next, his team developed a new statistical approach to examine how well changes in milk use through time explain the natural selection for lactase persistence.

Surprisingly, they found no relationship, even though they were able to show they could detect that relationship if it existed, challenging the long-held view the extent of milk use drove lactase persistence evolution.
Professor Davey Smith’s team had been probing the UK Biobank data, comprising genetic and medical data for more than 300,000 living individuals, and found only minimal differences in milk drinking behaviour between genetically lactase persistent and non-persistent people.

Critically, the large majority of people who were genetically lactase non-persistent experienced no short or long-term negative health effects when they consume milk. Professor Davey Smith added: “Our findings show milk use was widespread in Europe for at least 9,000 years, and healthy humans, even those who are not lactase persistent, could happily consume milk without getting ill.

However, drinking milk in lactase non-persistent individuals does lead to a high concentration of lactose in the intestine, which can draw fluid into the colon, and dehydration can result when this is combined with diarrhoeal disease.
Meanwhile, Professor Thomas had been thinking along related lines, but with more of an emphasis on prehistoric famines.

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He reasoned: “If you are healthy and lactase non-persistent, and you drink lots of milk, you may experience some discomfort, but you not going to die of it. However, if you are severely malnourished and have diarrhoea, then you’ve got life-threatening problems.

When their crops failed, prehistoric people would have been more likely to consume unfermented high-lactose milk – exactly when they shouldn’t.” To test these ideas, Professor Thomas’ team applied indicators of past famine and pathogen exposure into their statistical models.
Their results clearly supported both explanations – the lactase persistence gene variant was under stronger natural selection when there were indications of more famine and more pathogens.

The study involved collaborators from 21 countries, and was supported by funding from the Royal Society, the Medical Research Council (MRC), Natural Environment Research Council (NERC), and the European Research Council.

Why does milk last so long in Europe?

Ultra-heat-treated milk is a shelf staple, especially in tropical climes where milk easily spoils. BBC Future investigates its special properties. I In general, milk is not known for a spectacular shelf life. Even milk that’s been pasteurised, so a good many of the bacteria naturally present are dead, will go off after about 10-15 days in the fridge, and that’s being generous.

But for the last 50 or 60 years or so, milk that lasts not days, not weeks, but months and months without refrigeration has taken up a place on grocery store shelves.
The ubiquitous waxed-paper boxes contain milk that’s had an interesting treatment, with some effects that are obvious and others that you may find more surprising.

The process that leads to this UHT, or ultra-heat-treated, milk is incredibly brief, compared to normal pasteurisation. Named after Louis Pasteur, who pioneered the idea, pasteurisation is aimed at killing tuberculosis bacteria and a few others that cause disease. The milk can be stored for many months thanks to the sterilising effect of heat (Credit: iStock) However, in many European nations, UHT milk is the norm. This milk is heated to double the temperature – 140C – for a mere three seconds. The high heat does its work almost instantly, killing all bacteria and most of the bacterial spores that can stand up to lesser temperatures.

Because it’s nearly sterile, as long as it is packaged in a container that’s aseptic, it will last and last.
No bacteria means no spoilage, at least as long as the package is closed.
You can’t do just anything to UHT milk, cautions Deeth.
It’s designed to last at about 20-30C, so if it’s shipped across the equator on a sweltering ship, or languishes on a dock somewhere in the tropics for a while, some of those remaining spores may come active and cause problems.

And peculiar things do happen sometimes to that everlasting milk in its cloistered existence. It can form a gel inside the package, so when you open it and try to pour it, “it looks a bit like a yoghurt or a custard, or it has lumps,” says Deeth.