Learn about food safety when you sous vide
Food safety is one of the most misunderstood aspects of sous vide cooking. Is it safe to eat food boiled in a plastic bag? And the water in the water bath doesn’t even reach boiling temperature, that can’t be safe to eat! These are just some of the common misconceptions attached to sous vide cooking.
So let’s tackle these myths one by one.
MYTH: The process of vacuum-packing sucks out the moisture in meats and dries it out.
TRUTH: On the contrary, what the vacuum seal does is keep food from losing moisture to the air. It can even prevent discoloration caused by oxidation.
MYTH: Food that’s already been cooked sous vide should not be stored back in the fridge as it breeds bacteria growth.
TRUTH: Well, this is a half-truth. One of the biggest benefits of sous vide cooking is that it allows you to pre-cook your dish 2 days before and then on the day, reheat, sear and serve.
However, it is TRUE that food that’s just been cooked sous vide should not be IMMEDIATELY stored in the fridge. The proper process is to chill the vacuum-sealed bag in a ice bath straight away after cooking and only keep it in the fridge when it is good and thoroughly chilled. The reason is because it needs to be chilled QUICKLY. The ‘temperature danger-zone’ for food is between 4°C to 60°C (40°F to 140°F). It is in this temperature range that food bacteria can grow and multiply.
The most significant part of the ‘temperature danger-zone’ is between 40°C to 50°C (100°F to 120°F) and this is where bacteria growth is at its fastest. We want our food to spend as little time in this ‘danger-zone’ as possible. Hence the need to quickly chill the cooked food and then to keep it cold (at or below 3°C/38°F). To learn our tips on how to make a proper sous vide ice bath, you can click here.
It is important to note that you should put it in the freezer, instead of the fridge, if you’re not going to consume the food within 48 hours.
MYTH: You can vacuum-seal food that’s been defrosted to room temperature.
TRUTH: A big no-no. Only vacuum-seal food that’s chilled. Always.
MYTH: Sous vide cooking requires you to boil food in plastic bags and that’s not healthy.
TRUTH: Another half-truth. Yes, boiling food in a plastic bag isn’t healthy but sous vide cooking doesn’t do that! Firstly, the temperature in the water bath does not ever reach boiling temperature, not for any sous vide recipe. If it did, it wouldn’t be called sous vide! (Of course, the fact that temperatures in sous vide cooking never exceeds 85°C/185°F can cause other misconceptions which we address below.)
Secondly, the bags used in sous vide cooking are not just regular ‘plastic bags’. Only food-grade bags that are rated for sous vide cooking should be used. They should be BPA-free, phthalate-free and from a reliable source. For further reading on this, you can check out this link.
MYTH: The water in the sous vide water bath doesn’t even reach boiling temperature. That means that there’s still bacteria on it which means it is not safe.
TRUTH: In sous vide cooking, we use a balance of time and temperature to achieve proper pasteurization of our food. Pasteurization is the killing of pathogens in your food to make it safe for consumption. As long as you follow recommended time and temperature guidelines and observe proper food safety practices, then your food is safe to eat. Your food doesn’t need to reach boiling temperature in order to be safe.
OTHER FOOD SAFETY TIPS
- You should cut your food into serving-size and sous vide that rather than to sous vide one big chunk and then cut it down to size. The reason is that having a smaller serving size means the core of the food reaches the desired temperature faster. The less time your food spends in the ‘danger-zone’ the better.
- If you have 4 pieces of steak medallions that you want to cook sous vide, make sure you bag them in a single layer as opposed to stacking them up. As mentioned above, having a single layer means your food reaches the desired core temperature faster.
- Don’t crowd your water bath and make sure there’s room for the water to circulate around each bag. Otherwise your cooking times will all be off.
- Use tongs to handle your food when placing it in the bag to vacuum seal.
With all the points mentioned above, we need to of course mention that standard food hygiene rules must still be adhered to at all times. For a really in-depth discussion on food safety, we like this comprehensive document prepared by Hospitality Institute of Technology and Management (www.hi-tm.com). For your convenience, you can download it here.
So sous vide soon and bon appétit!