Cross contamination is the single biggest cause of food poisoning in the home. While we’re reasonably good at managing temperatures and cleanliness, the simple act of transport bacteria from one surface to another is something we still haven’t mastered.
There are two types of cross contamination, so perhaps it’s best to start by differentiating them.
Direct cross contamination
Direct cross contamination involves the transfer of food poisoning from one surface to another — without a “vehicle”. Here are a few examples:
- When juices from a steak drip onto cooked ham in the fridge
- When an infected fly lands on cooked food
- When infected cheese comes into contact with salad
All three of these examples involve food that isn’t going to reach the critical core temperature of 63C. As a result, the bacteria will be present when the food is consumed — with potentially dangerous consequences.
Indirect cross contamination
This is easily the most common type of cross contamination in domestic kitchens. Here are some examples:
- The same knife is used for infected red meat and salad vegetables
- The food handler touches raw chicken and cooked sausage without washing their hands
- Raw pork and bread are cut on the same chopping board
In all three examples, there is a vehicle — or a third party — involved. In the case of red meat and salad vegetables, it’s the knife.
Fortunately, stamping out cross contamination in the kitchen is relatively easy — but it requires organisation, discipline and common sense.
Observe good hand hygiene practices
One of the biggest causes of indirect cross contamination is dirty hands. But all you need to do in order to prevent any problems is to wash your hands regularly — and at the right times.
Keep some handwashing soap in your kitchen at all times, as well as some paper towels for drying.
- Wash your hands before handling food
- Wash your hands whenever you change activity (such as chopping veg and preparing meat)
- Wash your hands whenever you touch a dirty utensil
- Wash your hands every time you touch raw egg, raw meat and cooked rice
The average item of jewellery is usually a breeding ground for bacteria — particularly rings. Before you start preparing food, remove any rings and earrings, and put them away in a safe place.
Use separate and dedicated equipment
If you’ve ever worked in a professional kitchen, you’ll know that knives and chopping boards are colour-coded depending on the type of food they’re used to prepare. While you don’t need to go to these lengths, it’s important that you utilize separate areas of worktop for vegetables, raw meat and cooked meats. Also, use separate knives and chopping boards for each type of food.
Sanitise after every stage of food prep
Once you have finished prepping, say, your raw meat, clear the surface and coat it in a liquid sanitiser. Give it 30 seconds of contact time, then wipe it off with a clean cloth. This might seem like overkill, but half a minute of your cooking time will drastically reduce the chances of food poisoning in your home.
Arrange your fridge properly
Dedicate certain shelves in your fridge to certain products. Store cooked foods in sealed containers, and raw foods at the bottom of your fridge — making sure they’re wrapped or sealed. This will ensure raw and cooked foods never have to come into contact with one another.
Always use clean cloths
Another bacteria vehicle to be aware of is the humble kitchen cloth. Whether it’s a dish cloth, a tea towel or even a sponge, be conscious of what you’re using it on. For example, if you use a cloth to wipe down a meat prep area, you certainly shouldn’t be using it to dry your dinner plates.
Organise your kitchen, invest in the appropriate tools and remain disciplined and vigilant at all times. Not only that, make sure everyone in your home is doing the same. Just a little organisation and some common sense should minimise the risk of food poisoning caused by cross contamination.