Food Poisoning Risks from Leftovers: Expert Advice on Safe Storage
Experts emphasise that careful storage of leftovers is crucial to prevent health risks, as improper handling can lead to food poisoning from contaminated foods.
Understanding Food Poisoning from Leftovers
Food poisoning occurs when food becomes contaminated with pathogenic bacteria, fungi, or viruses. While many associate it with undercooked meals or poor preparation, leftovers stored incorrectly are a significant contributor. Taking precautions when storing leftovers is essential to safeguard your health.
Leftover Pizza: A Common Culprit
Cooked pizza can cause food poisoning through various means, such as raw or undercooked ingredients, contact with contaminated surfaces, or handling by unwashed hands. Surprisingly, dried herbs like basil and oregano may also carry microbial contaminants from harvesting or storage, potentially harbouring bacteria such as Salmonella or Bacillus cereus.
Even if heat sterilises these herbs during baking, leaving pizza at room temperature too long allows germs to thrive on toppings. To reduce risk, refrigerate leftovers within two hours of cooking or delivery. Store covered in the fridge and consume within two days, as refrigeration only slows bacterial growth. Pizza left out for hours becomes unsafe, regardless of appearance or smell.
Leftover Chicken: High Perishability
Cooked chicken is highly perishable due to its moisture, nutrients, and low acidity, which favour bacterial growth if stored improperly. Only save chicken that has been fully cooked; avoid any with blood in the juices, as this indicates undercooking and potential contamination with germs like Campylobacter or Salmonella.
After cooking, cover and refrigerate chicken promptly, ideally within two hours at room temperature. It can be stored for up to three days in the fridge, but discard if blood is present, as it may harbour harmful bacteria even when reheated.
Leftover Rice Dishes: Starchy Dangers
Rice dishes, including fried rice or risotto, pose a major food poisoning risk because uncooked rice can contain Bacillus cereus spores. Cooking kills the bacteria but not the heat-resistant spores. If left at room temperature for over two hours, these spores can germinate, multiply, and release toxins, causing severe vomiting and diarrhoea for up to 24 hours.
To stay safe, cover cooked rice, cool it quickly, and refrigerate for no more than 24 hours. Cold rice is safe if cooled and stored promptly, but consume within 24 hours to prevent spore germination.
Leftover Canned Foods: Acid Matters
For canned leftovers, cover and refrigerate to avoid airborne contamination. It is safe to store food in the original sterilised can, but transferring to a plastic or glass container may preserve flavour better. Highly acidic foods like canned tomatoes can last five to seven days refrigerated, while low-acidity items such as meat or vegetables should be consumed within three days, as acid inhibits bacterial growth.
In general, leftovers can be eaten cold if refrigerated quickly after cooking and consumed within a day or two to minimise health risks.
