The often-used and hazardous sniff test is not a foolproof way to check if leftovers are safe to eat. It might be safer to give whatever is hiding under tinfoil at the back of the fridge a miss because when it comes to those cost-saving leftovers, there are a few rules to follow to avoid the potential of eating something that has either been stored incorrectly or is past its use-by date. For the majority of people, food poisoning is usually not that serious, but far from being simply an unpleasant experience, food poisoning has the potential to lead to long-term illness or death, making food safety a very important issue.
Storing, preparing and serving up food is awash with myths and misconceptions that can be dangerous, resulting in food poisoning. But do we really know what we’re doing in the kitchen, can we prevent cross-contamination and just how should we reheat those leftovers?
To dispel some of the most confused myths about food safety, Dr Mary Lenahan, technical executive of biological safety at the Food Safety Authority of Ireland, helps to set the record straight on how we can be conscious of how we store and prepare our food.
Myth – Leftovers kept for a long time are safe to eat
“Leftovers are a great way of making the most of your budget,” says Dr Lenahan, “however, if you decide to chill or freeze leftovers to keep for later, make sure that you are storing leftover food safely to reduce the risk of possible food poisoning. For example, uncooked rice and pasta can contain spores of bacillus cereus, a bacteria that can cause foodborne illness. These spores can survive even when rice or pasta is cooked. If the rice or pasta is left standing at room temperature for greater than two hours, these spores can grow into bacteria. These bacteria can then multiply and produce toxins (poisons) that can cause foodborne illness, the symptoms of which include nausea, vomiting and abdominal cramps.”
To avoid this, Dr Lenahan suggests covering leftover food and storing it in the fridge at between 0-5 degrees or the freezer at -18 degrees or less within two hours of cooking. Use clean dishes and utensils for cooked food to prevent cross-contamination and throw away any high-risk food and all food scraps that have been standing at room temperature for more than two hours.
“Do not put food in the fridge or freezer when it is still hot,” Dr Lenahan also advises, “as it could raise the temperature of the fridge or freezer allowing other foods already stored in the fridge or freezer to get too warm.” Cool a large portion of food by dividing it into smaller amounts to speed up the cooling process and using them within two to three days if stored in the fridge or within six months if in the freezer.
When reheating leftovers, “to reduce the risk of food poisoning, food should be very hot and steaming before it is served”, advises Dr Lenahan, who also urges that leftovers should only be reheated once.
Myth - Cross-contamination doesn’t happen in a fridge
Keep your fridge nice and cold and bacteria will die. For some reason this myth perpetuates throughout our homes but it’s a dangerous fabrication that can lead to cross-contamination and the risk of food poisoning. In fact, most bacteria can survive the cold environment of your fridge with some, such as listeria monocytogenes, even growing in the cool and moist environment.
“Cross-contamination happens when bacteria or other microorganisms are unintentionally transferred from one object to another,” explains Dr Lenahan. “Foods of most concern are those that do not require any further cooking or reheating such as chilled ready-to-eat foods including soft cheeses, smoked fish, cooked sliced ready-to-eat deli meats and cured meats, pâté from meat, vegetables or fish, pre-packed salads and sandwiches, and pre-cooked ready-to-eat shellfish.”
Storing foods correctly, prepping foods and using utensils intentionally will help avoid cross-contamination. “Bacterial cross-contamination is most likely to happen when raw food touches or drips on to ready-to-eat or cooked food, utensils, or surfaces,” advises Dr Lenahan.
To avoid cross-contamination, store different foods in the correct areas of the fridge. For example, it is recommended to store ready-to-eat foods such as cheese, yoghurt, cooked meats, and leftovers on the middle and top shelves with raw meat, fish, and poultry in sealed containers on the bottom shelf, so they don’t touch each other or drip on to other foods.
Myth - It’s okay to thaw meat on the counter
Forgetting to take the meat out of the freezer for dinner is one of those tedious conundrums of life we routinely repeat. But leaving the chicken on the counter to defrost for hours is possibly worse than not taking it out at all.
“Remember that a freezer acts as a pause button, meaning food in a freezer won’t deteriorate and most bacteria cannot grow in it. But any bacteria present in the food at the time of freezing are still alive, meaning they may be revived and start growing again as the food starts to defrost,” says Dr Lenahan. The best option to avoid the risk of food poisoning is simple: defrost the dinner in the fridge instead.
Myth - I eat a vegetarian diet so don’t need to worry about food poisoning
“While many of us associate food poisoning with foods such as meat, cheese, eggs and seafood, there are plenty of plants and plant-based foods that can be contaminated with naturally occurring toxins, viruses and parasites,” says Dr Lenahan.
“High-risk foods that require little or no preparation and that do not go through a cooking “kill step” provide an ideal breeding ground for food-poisoning bacteria. High-risk foods include a range of plant-based foods and ingredients such as tofu, rice, raw sprouts, fresh fruits and vegetables, cooked lentils, pasta, beans, and chickpeas, pre-cut or pre-washed fruits and vegetables, unpasteurised fruit juices, herbs and spices, and nuts. Wash vegetables under a cold running tap and remove all soil before peeling and chopping.”
When it comes to food safety, many would struggle to connect a risk with their herbs and spices, but safe food storage can prevent contamination.
Myth – You should store your eggs in the cupboard
One of life’s quandaries is where to store the eggs. Your new fridge comes with a handy egg compartment, but your local household store sells rustic egg containers to proudly sit on your kitchen countertop, so which is the best option? Dr Lenahan has this food-safety riddle solved.
“Have you ever wondered why eggs are not refrigerated in retail outlets but the label on the packaging says the eggs should be stored in the fridge by consumers?” she asks. “The reason is that if eggs are refrigerated by the retailer there is the possibility that the cold eggs may become covered in condensation during transport home by the consumer. Condensation can facilitate growth of bacteria and moulds on the shell and probable entry into the egg. By keeping the eggs at a constant ambient temperature at retail level, this condensation does not occur.”
With that confusing twist solved, Dr Lenahan clearly advises that “eggs should be kept in the fridge after purchase”.
The point is to avoid changes in storage temperature which can lead to water condensation on the shell, promoting bacterial growth and penetration into the egg.