Food Safety
Food Poisoning Symptoms, Signs and When to Seek Help
Table of contents
Did you know that over 2.4 million cases of foodborne diseases are reported in the UK every year?
Food poisoning is far more common than many people realise, and while most cases are mild, some can be serious or even life-threatening if not treated promptly.
According to the Food Standards Agency (FSA), “Foodborne pathogens such as norovirus, Campylobacter, Listeria, Salmonella and Shiga toxin-producing Escherichia coli (STEC) cause approximately 2.4 million cases of disease in the UK population and impose an annual cost to society equivalent to £9.1 billion every year.”
Food poisoning is an acute illness caused by eating contaminated food. It can be the result of bacteria, viruses, parasites, or harmful chemicals in what we eat. Most people recover within a few days; however, some vulnerable groups, including children, older adults, and individuals with weakened immune systems, may require medical attention. In rare cases, it can become life-threatening.
That’s why understanding what causes food poisoning, how to spot the symptoms, and what to do when it strikes is essential for everyone.
Want to understand how food becomes contaminated?
Read our detailed guides on the Common Types of Food Contamination.
Learn how to prevent:
Cross-contamination, Microbial contamination, and Physical contamination.
What is Ptomaine Poisoning?
One outdated but still widely searched term for food poisoning is ptomaine poisoning. It originally referred to illnesses caused by toxic compounds (called putrefactive toxins, or ptomaines) formed when food decays due to bacterial activity. The term comes from the Greek word ptōma, meaning “fallen body” or “corpse”.
Today, what was once known as ptomaine poisoning is more accurately referred to as food poisoning.
Symptoms and Types of Food Poisoning
Food poisoning can be caused by different types of bacteria and viruses. Majorly, there are four types of Food poisoning, each with its own symptoms. Understanding the types and signs of food poisoning can help you take appropriate action.
Let’s look at the types of food poisoning, along with their symptoms and how they often make their way into our kitchens.
1. Salmonella
Salmonella bacteria often come from the intestines of animals and can transfer to food during processing or even through poor kitchen hygiene. It’s especially common in:
- Undercooked chicken
- Raw eggs (think homemade tiramisu or runny boiled eggs)
- Unpasteurised milk
- Contaminated fruits or vegetables
Example: Let’s say you’re baking a cake and lick the spoon after mixing raw eggs into the batter. If those eggs carry salmonella, that one small taste could make you sick.
Symptoms: Diarrhoea, fever, stomach cramps, and vomiting—usually starting within 6 to 72 hours and lasting 4 to 7 days.
2. Campylobacter
Campylobacter is the most common cause of food poisoning in the UK, and it doesn’t take much bacteria to cause illness. It’s typically found in:
- Undercooked poultry (especially chicken)
- Red meat
- Unpasteurised milk
- Contaminated water
Example: Suppose you grill some chicken but only check if it’s cooked by cutting near the edge. The inside is still pink, but you don’t notice and serve it anyway. That undercooked middle could be carrying campylobacter, especially in barbecue or busy dinner settings.
Symptoms: Diarrhoea, abdominal pain, fever, and flu-like symptoms. They usually appear 2 to 5 days after exposure.
👉 Check out our article on food safety hazards to learn how to spot and prevent common food safety mistakes.
3. E. coli
coli—especially the strain O157—can cause serious illness and is known to survive on surfaces like stainless steel for weeks.
You could be exposed to E. coli through:
- Rare or undercooked minced meat (like a medium-rare burger)
- Raw vegetables
- Unpasteurised dairy
- Contaminated water
Example: Even a garden salad that hasn’t been appropriately washed can carry this bacteria, mainly if grown in fertilised soil or irrigated with untreated water.
Symptoms: Usually appear within 1 to 3 days and include severe stomach cramps, diarrhoea, vomiting, and sometimes fever. The illness can last up to two weeks.
4. Listeria
Listeria monocytogenes causes listeriosis, which is particularly dangerous for pregnant women and older adults. What makes listeria tricky is that it can grow even in cold temperatures, like your fridge.
High-risk foods include:
- Ready-to-eat deli meats
- Soft cheeses like camembert and brie
- Pre-packed sandwiches or salads
- Unpasteurised milk
So, if you’ve left a pack of sliced ham or a soft cheese open in the fridge for a few days, it might be time to double-check its shelf life and toss it if unsure.
For more information, check out our article Difference Between Use By and Best Before Dates
Example: Imagine grabbing a pre-packed ham sandwich or some brie from the fridge. If these haven’t been stored properly or have passed their use-by date, Listeria can grow, even in cold temperatures and can lead to severe illness.
Symptoms: Nausea, vomiting, diarrhoea, and fever. These symptoms may appear anywhere from a few days to several weeks after consuming contaminated food.
5. Viruses (Norovirus and Hepatitis E)
While bacteria are the usual suspects, viruses can also cause foodborne illness. The two most common culprits are:
- Norovirus – Known as the “winter vomiting bug,” it spreads easily through contaminated hands, surfaces, and food. Just imagine someone sick prepping your sandwich without washing their hands—yep, that’s how quickly it spreads.
- Hepatitis E – This virus is often linked to undercooked pork and poor hygiene. Always ensure pork products are cooked until steaming hot, with no pink in the middle and juices running clear.
Example: You’re at a family barbecue, and someone serves pork sausages that look a little pink in the middle. If that pork isn’t cooked all the way through, there’s a risk of Hepatitis E.
Symptoms:
For Norovirus – Sudden vomiting, diarrhoea, and stomach cramps.
For Hepatitis E – Symptoms in severe cases include fatigue, nausea, and jaundice.
To reduce the spread of viruses, follow proper handwashing techniques and safe food handling practices.
Common Causes of Food Poisoning
Food poisoning is caused by eating food that’s been contaminated with harmful bacteria, viruses, or toxins. Contamination can occur at any stage, from growing and harvesting to processing, storing, transporting, or preparing food.
There’s no single cause of food poisoning – it can result from a number of issues throughout the food journey.
Below are the most common causes:
- Storing hot or cold food at incorrect temperatures
-Want to understand more about the correct temperature range? Read our article on the Temperature Danger Zone to learn how to keep food safe. - Cooling food too slowly before putting it in the fridge
- Buying food from untrustworthy suppliers
- Undercooking food, especially meat and poultry
- Not defrosting food properly before cooking, especially chicken and turkey
-Not sure how to do it safely? Here’s our guide on How to Defrost Food the right way. - Cross-contamination between raw and ready-to-eat food
- Eating raw or undercooked foods
- Food being touched by someone who is ill or hasn’t washed their hands properly
- Not reheating food thoroughly
-Wondering how to do it right? Read our guide on Safe Food Reheating to avoid risks.
These issues can occur anywhere, including homes, restaurants, catering kitchens, or manufacturing plants.
Essential Food Safety Courses for Every Role
No matter your position, whether you’re a Staff Member, Manager, or Supervisor, knowing how to safely handle food is essential for maintaining hygiene standards and protecting public health.
To stay compliant and reduce the risk of foodborne illness, explore Hurak’s Food Safety courses below:
Each course is tailored to meet your role-specific responsibilities and industry requirements.
Which Foods Can Cause Food Poisoning?
Almost any food can make you sick if it’s contaminated. But some foods are more likely to cause food poisoning because they help bacteria grow, especially when they’re high in protein or moisture.
Food can be categorised into two main groups: low-risk and high-risk.
Low-Risk Foods
These are foods that don’t support bacterial growth easily. They usually have little moisture or are preserved with salt, sugar, or acid.
Examples include:
- Cereals
- Canned foods
- Dried pasta
- Dried rice
However, caution is key—once you add water or cook them, they become high-risk and must be stored and handled safely to prevent bacterial contamination.
High-Risk Foods
These foods support rapid bacterial growth when not handled properly and are often eaten without further cooking.. That makes it easier for harmful microbes to survive and multiply.
Examples of high-risk foods:
- Cooked meat and poultry
- Meat dishes like stews or pâtés
- Pies and pasties
- Sauces, soups, stocks, and gravies
- Shellfish (like prawns, oysters, and crab)
- Foods made with raw eggs, like mayonnaise
- Dairy products
- Cooked rice
To keep food safe, it’s crucial to store high-risk items at the correct temperatures and keep them separate from raw foods. Even items like raw salad and vegetables should be washed thoroughly under clean running water before consumption to reduce the risk of contamination.
Want to learn more? Explore our guide on Fridge storage and High-risk foods.
Who Is Most at Risk of Food Poisoning?
Some people are more likely to get seriously ill from food poisoning. If you’re preparing food for them, take extra care with hygiene, storage, and cooking.
People who are especially vulnerable include:
- Pregnant women
- Older adults
- Babies and young children
- People with long-term health conditions or weakened immune systems
For these groups, even a minor mistake can have serious consequences.
Diagnosing and Treating Food Poisoning
Food poisoning can be unpleasant, but it doesn’t always require a trip to the doctor. Most cases can be managed safely at home with rest and care.
Signs of Food Poisoning
If you’ve eaten something contaminated, symptoms typically appear within a few hours to a couple of days. The most common signs include:
- Feeling or being sick
- Diarrhoea
- Stomach cramps
- A high temperature
- Aching muscles
- Chills and tiredness
These symptoms usually last for a few days, and most people recover without needing medical help.
Treatment: What to Do If You Have Food Poisoning
If you’re experiencing mild symptoms, follow these steps to help your body recover:
- Stay at home and rest — Avoid work, school, or socialising until at least 48 hours after symptoms stop
- Drink plenty of fluids — Small sips of water, clear broth, or rehydration drinks help prevent dehydration
- Eat light meals — Stick to bland foods like toast, rice, or bananas once you feel ready to eat
- Avoid caffeine, alcohol, and spicy or fatty foods until you’ve fully recovered
- Call your family doctor (GP) if you want reassurance or need advice; they may recommend medication to relieve symptoms
Most people don’t need antibiotics. Just focus on hydration and rest.
When to See a Doctor
While food poisoning is often mild, some situations require medical attention, especially if you’re in a vulnerable group or showing more serious signs.
See your GP, call NHS 111, or get urgent help if:
- You can’t keep any fluids down because of vomiting
- Symptoms haven’t improved after a few days
- You show signs of severe dehydration, such as:
- Rapid heartbeat
- Little or no urine
- You’re pregnant
- You’re over 60
- Your baby or child shows signs of food poisoning
- You have a long-term health condition, like diabetes, kidney disease, or IBD
- You have a weakened immune system due to chemotherapy, medication, or HIV
📞 If you’re experiencing severe symptoms and can’t visit a doctor, call NHS 111 for advice and support.
How Long Does Food Poisoning Last?
For most people, food poisoning clears up within 1 to 3 days; however, some symptoms, such as tiredness or an upset stomach, may persist for a bit longer. Ensure you rest well, stay hydrated, and avoid high-risk foods during recovery.
What to Eat vs What to Avoid During Food Poisoning
How to Prevent Food Poisoning
Preventing food poisoning comes down to a few simple habits:
Cleanliness, Cooking, Chilling, and Avoiding Cross-Contamination.
- Wash hands, worktops, and dishcloths regularly using hot, soapy water to stop germs from spreading
- Use separate chopping boards for raw and ready-to-eat foods to prevent cross-contamination
-Read our article on Different Colour Coded Chopping Boards to better understand the correct usage of each chopping board in food preparation
- Store raw meat properly—covered and on the bottom shelf of the fridge – away from other foods
- Cook food thoroughly until it’s steaming hot with no pink inside; never wash raw meat before cooking
- Keep your fridge at a temperature below 5°C and avoid overfilling it to ensure proper air circulation
-For proper fridge temperature maintenance, read our article on Fridge Storage Temperature
- Cool and store leftovers quickly, ideally within 90 minutes, and eat refrigerated food within 2 days
- Always check use-by dates and don’t eat food that’s past them, even if it looks fine
-For a detailed understanding, read our article on Difference Between Used By and Best Before Dates
How to Report a Food Safety or Hygiene Issue
If you’ve experienced a food safety or hygiene problem, like suspected food poisoning, poor hygiene at a food business, mouldy food, or missing allergen information, you can report it to the local authority.
Common issues you can report include:
- Suspected food poisoning
- Foreign objects in food
- Dirty premises or poor hand hygiene
- Unsafe food handling
- Out-of-date food
- Incorrect or missing allergen information
Use the Food Standards Agency article below to find your local food safety team and make a report:
🔗 Report a Food Safety or Hygiene Issue
Summary
In this article, we’ve explored the key points about ptomaine poisoning – from common foodborne pathogens and high-risk foods to safer options when you’re unwell and when to seek medical advice.
Understanding food safety is not only crucial for preventing food poisoning, but it is especially important if you work in the food or hospitality industry. With numerous customers to serve and risks that can arise at any time, paying close attention to even the smallest details is crucial for maintaining public safety and ensuring smooth day-to-day operations.
👉 Take the next step and get certified
Book our Food Hygiene and Safety Course, designed to meet real-world food safety needs.
FAQs
What is ptomaine poisoning from canned food?
Ptomaine poisoning was once a term used to describe food poisoning caused by bacteria in rotting food, especially canned food. While the term is outdated, the concern is still real—eating improperly canned food can cause serious illnesses like botulism, which can be life-threatening. Always check for bulging lids, rust, or unusual smells before consuming canned food.
What are the symptoms of ptomaine poisoning?
Although “ptomaine poisoning” isn’t a medical term used today, it generally refers to symptoms similar to food poisoning—nausea, vomiting, stomach cramps, and diarrhoea. If symptoms appear after eating canned or preserved food, especially if it tastes “off,” seek medical advice immediately.
How long does food poisoning last?
Food poisoning typically lasts from a few hours to a few days, depending on the cause and severity. Mild cases clear up in 1–3 days, while more serious ones, such as those caused by E. coli or Listeria, can take a week or more and may require medical treatment.
What are the symptoms of food poisoning?
Common food poisoning symptoms include:
- Nausea
- Vomiting
- Diarrhoea
- Stomach cramps
- Fever
- Weakness or fatigue
These symptoms can start within a few hours of consuming contaminated food or may take days to appear, depending on the specific bacteria or virus involved.
What is the most common cause of food poisoning?
In the UK, Campylobacter is the most common bacterial cause of food poisoning, often found in undercooked poultry.
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