Can Boiling Kill Cat Germs in Licked Milk?

Can Drinking Milk Licked by a Stray Cat Make You Sick?

Many of us have been in the situation where we accidentally leave a glass of milk unattended, only to return and find a neighborhood cat helping itself to a few licks. While startled, your first instinct may be to toss the contaminated milk down the drain. But if it’s the last of the carton, you might also consider: Could I safely drink this milk if I boil it first? It’s an understandable question, given the rising costs of groceries these days.

In this article, we’ll explore the potential risks of consuming milk that has been exposed to a stray cat’s saliva. We’ll look at some of the dangerous diseases cats can transmit, and whether boiling is an effective method to kill any pathogens. We’ll also provide proper storage and handling tips, as well as alternative options if you find yourself in this situation. After all, when it comes to food safety, it’s always better to be cautious if you’re ever in doubt.

Risks of Consuming Contaminated Milk

Consuming raw milk that has been contaminated with pathogens can pose serious health risks. When a stray cat licks milk, the saliva can transmit dangerous bacteria, viruses, and parasites into the milk, including Salmonella, E. coli, Listeria, Campylobacter, Toxoplasma gondii, and rabies virus. These pathogens can cause severe gastrointestinal illness if the contaminated milk is consumed raw. Symptoms may include vomiting, diarrhea, fever, and abdominal cramps. In some cases, illness can lead to hospitalization or long-term health consequences. Vulnerable populations like children, the elderly, pregnant women, and those who are immunocompromised are at highest risk of severe infection or complications.

Common Diseases Transmitted by Cats

Cats can transmit a number of diseases to humans that pet owners should be aware of. Three of the most concerning diseases that can be passed from cats to humans include:


Toxoplasmosis is an infection caused by the Toxoplasma gondii parasite. Cats are the definitive host for this parasite, which means it can complete its entire lifecycle in the cat’s body. The parasite is shed in the cat’s feces, and humans can become infected by accidentally ingesting contaminated cat feces, often by not washing hands after cleaning a litter box. According to the AVMA, toxoplasmosis infections are usually mild or asymptomatic in healthy adults, but the disease can cause serious illness in immunocompromised people and pregnant women, possibly leading to birth defects or miscarriage (AVMA).


Rabies is a viral disease that affects the central nervous system. It is almost always fatal once symptoms appear. Cats are one of the most common domestic animals to transmit rabies to humans through bites and scratches. According to the CDC, cats accounted for 304 or 24.5% of the 1,240 rabid domestic animals reported in 2020 (AAFP). Vaccinating cats is crucial to preventing the spread of rabies.


Ringworm is a contagious fungal skin infection that causes ring-shaped red lesions on the skin. The CDC reports that about 10-15% of cats carry the ringworm fungus at any given time. Humans can catch ringworm through direct contact with an infected cat’s skin or fur. Ringworm is highly contagious and can spread rapidly in group-living situations like schools, daycares, and shelters (CDC). Keeping cats healthy and grooming them regularly can help prevent ringworm transmission.

Effectiveness of Boiling Milk

Boiling milk can kill many harmful bacteria and pathogens. According to the NHS, boiling water for at least 10 minutes is an effective way to sterilize feeding equipment for babies. This is because the high temperatures reached when boiling water (212°F/100°C) are sufficient to kill most vegetative bacteria, viruses, fungi and other disease-causing organisms.1

However, boiling may not kill more resistant organisms like bacterial spores and certain parasites. The NHS recommends using freshly boiled water to make up formula for babies. But if milk has been exposed to contamination, especially from cats who can harbor parasites like Toxoplasma in their feces, boiling may not make the milk completely safe for consumption.2

So while boiling contaminated milk will destroy many potential pathogens, some viruses and parasites may still survive and present a health risk if consumed. Boiling cannot guarantee completely sterile milk if it has already been contaminated by a stray cat.

Proper Storage and Handling

It’s important to store and handle milk properly to avoid foodborne illness. According to the CDC, breast milk can be stored at room temperature for up to 4 hours, in the refrigerator for up to 4 days, and in the freezer for up to 6 months

Pasteurization is a process that heats milk to a specific temperature for a period of time to kill harmful bacteria. The CDC recommends heating breast milk to at least 145°F for 30 minutes if the milk is suspected to be contaminated. This process will kill most viruses and bacteria, including those that can cause food poisoning

Properly refrigerating and pasteurizing milk are important steps to avoid foodborne illnesses. If milk is suspected to be contaminated, it’s best to err on the side of caution and either pasteurize it or discard it.

Alternatives to Consuming High-Risk Milk

If milk may have been contaminated by a stray cat, the safest option is to discard it entirely. While boiling contaminated milk can reduce some risk, it does not completely eliminate dangerous pathogens. Consuming such milk still poses a health hazard.

Rather than take a chance with contaminated milk, consider these safer alternatives:

  • Pour the milk down the drain or sink so it cannot be consumed.
  • Use the milk for non-food purposes, like watering plants. Be sure to avoid any edible plants.
  • Place the milk in a sealed container and dispose of it with your regular household trash.

Throwing out questionable milk may feel wasteful, but it pales in comparison to the risks of foodborne illness. Your health is not worth compromising over a carton of milk. When in doubt, it’s always best to play it safe and discard milk that may have been contaminated.

When in Doubt, Throw it Out

When it comes to food safety, it’s always better to err on the side of caution. As the old saying goes, “when in doubt, throw it out.” This is especially true when dealing with unpasteurized dairy products that have potentially been contaminated by stray animals.

Milk licked by a stray cat could potentially contain harmful pathogens like Salmonella, E. coli, and Listeria. While bringing the milk to a boil may kill some of these germs, it’s not guaranteed to kill them all or make the milk completely safe for consumption [1]. As such, the precautionary principle recommends not taking any chances and simply discarding the milk.

Consuming contaminated dairy can lead to serious foodborne illnesses. Symptoms may include nausea, vomiting, stomach cramps, diarrhea, headache, and fever [2]. In severe cases, it can even lead to hospitalization. No one wants to get sick from drinking milk, so if there’s any doubt about its safety or origin, it’s better to just throw it out.

Following the precautionary principle allows you to avoid needless risks. When it comes to your health, peace of mind is priceless. Next time you encounter milk that could be contaminated, remember—when in doubt, throw it out.

Seeking Medical Care if Illness Occurs

If you develop symptoms of a foodborne illness after consuming milk that may have been contaminated, it is important to seek medical care. Symptoms of foodborne illness can include nausea, vomiting, stomach cramps, diarrhea, fever, and headache. These symptoms may start within hours after consuming contaminated food or they may take weeks to develop, depending on the pathogen involved.

Certain pathogens like E. coli, Salmonella, and Listeria can cause severe illness and complications. High risk groups like young children, pregnant women, older adults and those with weakened immune systems are more likely to develop severe illness that requires medical treatment.

According to the CDC, around 48 million people get sick from a foodborne illness each year in the United States. Of these, around 128,000 are hospitalized and 3,000 die each year. Seeking prompt medical attention can help prevent complications and reduce the risk of serious outcomes.

Healthcare professionals can provide rehydration therapy for dehydration caused by diarrhea, guide antibiotic treatment if needed, and collect stool samples to identify the pathogen responsible for the illness. They can also monitor those at high risk for complications like blood stream infections, kidney failure, and neurological problems.

Do not wait for symptoms to resolve on their own. Seek medical care promptly if you experience multiple or severe symptoms of foodborne illness after consuming potentially contaminated milk. Early treatment can significantly improve outcomes.


Preventing Exposure in the First Place

The best way to avoid contracting a disease from contaminated milk is to prevent the milk from becoming contaminated in the first place. Here are some tips for preventing exposure when handling food and beverages:

  • Avoid contact with stray animals. Do not allow them to lick or interact with your food, dishes, utensils, etc. Keep stray animals out of food preparation and storage areas.
  • Wash your hands thoroughly with soap and warm water before and after handling food. This helps prevent the spread of germs from hands to food. CDC recommends scrubbing hands vigorously for at least 20 seconds.
  • Sanitize kitchen surfaces, cutting boards, dishes, utensils and anything else that contacts food. Use a commercially available kitchen sanitizer or a bleach solution.
  • Rinse fruits and vegetables thoroughly under running water before eating, cutting or cooking. This removes dirt and other contaminants.
  • Keep foods at proper temperatures. Store perishable foods like milk in the refrigerator at or below 40°F. Cook meats to the recommended safe internal temperatures to kill any pathogens present.
  • Avoid cross-contaminating foods by keeping raw meats, poultry, seafood, and eggs away from ready-to-eat foods either in the grocery cart, refrigerator, or during food prep.
  • Do not consume foods that are past their expiration or use-by dates. Pathogen growth is more likely in older foods.

Following basic food safety principles helps minimize the chances of food or beverages becoming contaminated in the first place.


In summary, it’s generally not recommended to consume milk that has been contaminated by stray cats. Diseases like toxoplasmosis pose a real risk, and boiling milk may not eliminate the pathogens completely. The safest option is to discard any milk that has been exposed to questionable hygienic conditions.

If you do choose to drink milk licked by a stray cat after boiling, be aware you are taking a calculated risk. Try to boil the milk thoroughly, refrigerate it promptly after heating, and inspect carefully for any signs of spoilage. However, there is no guarantee this will make the milk safe.

The best prevention is keeping stray cats away from food prep areas. But if milk does become contaminated, err on the side of caution. When in doubt, throw it out. Your health is not worth the small benefit of consuming questionable milk.

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