Food Safety Basics
Preparing and cooking your own food doesn't have to be a minefield once you know how to be safe about it! This article aims to cover the most important parts of food safety for those who are unsure about it or just beginning to prepare food for themselves.
Cooking for yourself and your friends and family is an important life skill that's well worth learning, and once the fear of poisoning yourself is gone, it can be extremely rewarding and a lot of fun. So, let's get down to the basics of food safety.
1. The Temperature Danger Zone
The temperature danger zone is probably the most important concept in food safety. It's between 4˚C (40˚F) and 60˚C (140˚F), which is the temperature zone in which food-borne bacteria multiply rapidly.
Within four hours in this temperature zone, bacteria on food will likely have multiplied to dangerous levels and should be discarded.
Refrigerators need to be set below the minimum end of the scale; that is, they should be colder than 4˚C/40˚F to ensure that bacterial growth is kept to a minimum. Refrigerating food extends its life considerably.
When being kept warm, the internal temperature of food must be above 60˚C/140˚F (this applies to refrigerated temperatures also, but it's easier to cool food all the way through than it is to heat it all the way through).
Freezing food slows bacterial growth almost to a complete halt, though frozen food does not remain safe indefinitely (more on that further down).
2. High-Risk Foods
We all know that raw poultry and fresh seafood are high-risk, but what other foods do you need to watch out for? Here are a few you might not have known about:
- Cooked rice, pasta, and noodles. The high carbohydrate and moisture content of these foods make them an ideal breeding ground for bacteria (and mold, if left long enough).
- Milk, cream, and soft cheeses. Again, these are risky because of their high sugar and moisture content. Soft cheeses are also in this category, though refrigerated properly, and should last much longer.
- Ice cream! I know you never thought ice cream would hurt you, but with barely-cooked eggs and milk, it can be high risk. Ever seen that gooey, slightly darker crust on an opened tub? That's a film of bacteria.
- Fresh fruit and veggies. At a bare minimum, these need to be washed thoroughly before eating. It's not just food-borne bacteria you need to worry about with fresh produce, but soil-borne bacteria and the ingredients in pesticides (even organic ones) and fertilisers. (You understand that 'organic fertiliser' probably means 'chicken poop', right? You don't want to eat that.)
- Eggs. Whether raw eggs are high-risk or not will largely depend on hygiene practices where you live. However, cooked, or worse, semi-cooked eggs are very high-risk foods and should be consumed quickly or refrigerated and not allowed to sit for longer than necessary.
3. How to Freeze Food Right
Some food safety charts assert that frozen food will remain safe indefinitely. In ideal conditions, this would be true, but if you've found a way to get your freezer to a state of 'ideal conditions,' I would love to know all your secrets.
That said, freezing food is a great way to preserve it long-term. Provided you freeze it properly wrapped in cling film or in the original packaging, food can be kept for a year or longer in a good freezer.
- Freeze food sooner rather than later. It is very important that food be as fresh as possible when you freeze it, so if you know you aren't going to use it before it spoils, you should freeze it straight away rather than waiting until the last minute. Freezing works by halting the growth of bacteria, so having fewer bacteria in the food before you freeze gives you the best chance at having it come out safe and tasty (see chart below).
- Use defrosted food within 36 hours. If frozen food defrosts partially or fully, use it within 36 hours. Do not, under any circumstances, re-freeze defrosted food.
- Don't eat frozen food with torn packaging. If the covering on your food has torn, leaked, or is otherwise damaged, discard it.
- Trust your senses! If anything doesn't look or smell right when you defrost it, discard it.
- Defrost in the microwave or the fridge. Do not defrost frozen food on the bench. Either apply heat (like the defrost setting on your microwave) or let it defrost in the fridge. Placing it on the bench to defrost exposes food to the temperature danger zone (discussed above), potentially for much longer than the safe period.
Ideal Freezing Times Chart
|Type of Food||Maximum Freezing Time|
Ground/Minced meats (hamburgers, sausages etc.)
Soups and Stews
Raw eggs (cracked open and scrambled)
Raw egg whites
4. Safe Food Storage and Handling
Do you know that the way you store food in your fridge and the order in which you handle it is important? A lot of people don't, but the truth is that food can be kept much safer just by following a few simple rules.
Food storage rules:
- Stack your fridge correctly. Always store the highest-risk uncooked foods at the bottom, so they can't drip onto lower-risk or uncooked foods. Poultry and seafood should be stored on the bottom shelf, other meats above them, and cooked food and dairy above that.
- Make sure food is well-covered in the fridge. Not only does this increase shelf life, but it also avoids cross-contamination of foods.
- Clean your fridge regularly! Any spills or drips should be cleaned straight away, but a good deep-clean of your fridge every few weeks is also essential in maintaining good food hygiene. It's easy to forget or not think about, but it's very important.
Food handling rules:
- Always use clean knives and other utensils when handling food. Do not use the same utensils for cooked food as you have for uncooked food. Also, don't, for example, take a spoon of mustard out of the jar, use the spoon to rub the mustard on a chicken, and then put the spoon back in the jar. Because it's highly unlikely you're going to heat the mustard (or any other condiment) up enough next time you use it to kill all the bacteria you just introduced.
- Be careful when cutting raw meats. Likewise, turn your cutting board over between raw and cooked foods. Ideally, do not cut meat and vegetables on the same board (in fact, ideally, get a set of colour-coded cutting boards and stick to cutting different things on different colours).
- Wash your hands! Wash your hands after handling anything raw before you handle anything cooked, as well as after touching your hair or face.
5. Knife Safety
This is one you probably don't hear about a lot, but it's really important to know how to be safe with your knives in the kitchen.
Keep Blades Sharp
The most important thing regarding knife safety is to make sure your knives are always as sharp as possible and not damaged in any way.
It may seem counter-intuitive, but you're much more likely to hurt yourself with a blunt knife than you are with one that's been properly sharpened. A blunt knife requires you to use more force to cut, which means that if you do slip, you could easily do yourself a serious injury, as opposed to the small cut you might get with a very sharp knife.
Replace Knives With Thin Blades
Likewise, it's important to replace your knives when the blade gets too thin; a knife that's been sharpened so often that the blade is starting to thin out becomes a breaking hazard, and the last thing you want is to have the tip of your knife snap off while you're preparing dinner—it could end up anywhere!
6. Cooking Temperatures
So, now you know how to store and handle food safely, but what about cooking it?
Basically, the minimum safe internal temperature for any cooked food is 85˚C/185˚F, but many foods require a higher internal temperature to be truly safe (or, indeed, to go through the appropriate chemical changes to taste cooked).
For most things, it's easy to tell if food is cooked—it will look and smell like it is, and being able to see the surface or perform an easy test, like sticking a fork in it is enough. However, when it comes to things like roast meats—especially roast poultry—or larger serving sizes, things can get tricky.
Chefs and other experienced cooks often have tricks to determine whether food has been cooked to a safe internal temperature, but if you haven't got the experience to fall back on, your best bet is to get an inexpensive meat thermometer. They're very easy to use; you just insert them into the meat or dish you're preparing and cook until the correct internal temperature is reached. They're often marked with optimal internal temperatures for common types of meat, so it's very easy to see whether your food is safe (and delicious!).
This is especially handy with home ovens, which may not actually be heating to the temperature it says on the dial for a number of reasons.
7. How Do You Tell if Food Has Gone Off?
My food hygiene teacher had a saying—well, not a saying so much as a sentiment he was determined to bludgeon into us—that if any of your five primary senses are telling you there's something wrong with a food, toss it. So, with that in mind ...
- Smell: This is probably your most useful sense in telling whether food has gone bad. If food smells unpleasant or very strong, it's probably time to throw it out. If something doesn't smell the way you expect it to, it's probably also time to throw it out.
- Sight: Can you see mold, discolouration, or foreign particles? Chuck it.
- Taste: Taste a tiny bit of food you're not sure about. If it tastes bad, it's gone. This is especially useful in identifying expired dairy products because they taste really awful once they go bad. (Obviously, try not to throw out that milk your grandma was purposely souring so she could make yoghurt.)
- Touch: Ever poked your finger into a rotten fruit? Aside from being a really unpleasant experience, poking or squeezing fresh fruit and vegetables is a good way to determine whether they're still good. Most fruits should be reasonably firm with a little give. Most vegetables should be very firm.
- Hearing: The squeamish may want to stop reading here, but if you store grains, nuts or dried fruit, you may want to open your ears every now and again for insect activity. You won't always be able to hear them, but by the time you can, you'll want to throw out the whole bag (or, if you're me, get someone else to do it). Screaming like a baby is optional.
8. If You're Not Sure, Toss It
This is the biggest rule of home food safety. If you're not sure whether a food is safe to eat or not, just don't eat it. Throw it away. You are much better off chucking it out than risking your life or health over it.
If all else fails, I understand you can actually live on instant potato mash and butter with few ill effects, and both store exceptionally well (though you shouldn't store made-up instant mash for more than a few days).
© 2013 Cecil Wilde