This is a French phrase which means “under vacuum”. As a cooking term, it is a method of preparing food under vacuum in closed plastic pouches at specific temperatures (normally between 470C and 880C usually done in a water bath to regulate the temperature) for a rather long period.
This sounds like a new method of cooking, although it has a long history in France as well as several other international marketplaces. For instance, in Hong Kong, Sous Vide meals are available in restaurants and are also cooked at home.
The Sous-vide meals vacuum sealing lets the heat to be sufficiently transferred from the water to the meal, and it expands the foods shelf life by getting rid of potential contamination while in storage. These meals are thus appropriate for consumption in food services and retail sale. This culinary method can as well be used to cook favorite meals that cannot be attained by using contemporary cooking methods.
For instance, it prevents off-flavors as a result of oxidation and constrains losses of flavor volatiles as well as moisture from evaporation. The particular temperature control also lets close to perfect reproducibility (improved restrict over doneness) and turns the tough meat cuts to tender ones.
Food Safety When Using the Sous Vide Method
Cooking using the sous vide method is extremely safe due to its accuracy and control. Most meals are prepared at or over 54.50C to decrease the risk of growth of unsafe bacteria. If you prepare your meals below this temperature, you should sear meat before placing it in the water bath to eliminate surface bacteria. It is essential to rapidly freeze foods if you want to keep them in the fridge. Below are some tips on how to use this culinary method and avoid food poisoning and contamination:
1. Do not prepare meals beneath 54.40 C for over a few hours
From the point of safety, preparing meals below 54.40C is not cooking; it’s merely warming. The bacteria you are trying to eliminate from cooking blossom from approximately 4.40C to 52.20C, and they finish growing and do not begin dying fast until approximately 54.40C. This temperature range is known as the “danger zone”, and it is normally referred to in this way in food safety encircles.
At times the danger zone is considered to be up to 600C although this figure is based on a margin of error for eateries and not the growth and death of bacteria. Preparing meat below 54.40C is the same as letting it sit on the counter. It`s okay for a few hours, although it`s not something you will want to do the whole day. A normally embraced safe general time within the danger zone from removing it from the fridge to preparing and eating is about 3 to 4 hours.
Any meal which requires preparing for more than some few hours should be prepared at a 54.40 C minimum temperature. One thing to remember while Sous vide cooking is to have the meals between 4.40 C and 54.40 C for several hours.
2. Check your circulator`s temperature
Many Sous vide circulators are quite specific, and the temperature does not change much. Although, they can at times become uncalibrated and heat to the incorrect temperatures usually by one degree or two. If you go past the danger zone, that degree could make the difference between unsafe and safe meals.
Due to this possible calibration issue, it is advisable to double-check the circulator`s temperature every few days with a different thermometer.
3. Ensure to pasteurize some foods
At times when preparing meals, you want to make sure the food is pasteurized, not simply heated through. This is specifically essential for poultry, low-quality fish and blade-tenderized steaks.
Pasteurization takes place when the meal is held at a particular temperature for a specific period. The food is usually pasteurized faster as the temperature rises. Also, raw food should not be stored for over two days before pasteurizing it, cooling it under 30C within 120 minutes and that pasteurized meal should be served immediately or kept below 30C as recommended by the chef.
Sous vide pasteurization is attained when the inner food core temperature is placed long enough to attain a 6.5-log bacterial reduction. Generally decreasing bacterial loads by 6.5-Logs is acceptable for many pasteurized meals, except poultry, where bacteria reduction for salmonella is 7 Logs. A bacteria reduction of 6-Log is translated into 99.9 % decrease of bacteria.
4. Vacuum packaging
For packaging the meals for quality and safety, see the tips below:
a) The meals must be frozen before vacuum packaging
This is usually quality and not necessarily a safety issue. Air pressure reduces the liquid`s boiling point, meals not frozen before vacuum packaging may result in overcooking or cooking the meal unevenly.
b) Vacuum package the meals is one layer and do not overlap food within the bag
This allows for the fastest and sufficient heat transfer during immersion in the water. Do not forget that thicker foods will need a more extended period for even cooking, or come up time.
c) Vacuum Package each serving in a different pouch
If you pack bulk packages, all the serving should be used simultaneously, resealing is not an option. Opening the sealed package reduces its shelf life. Do not reseal upon opening.
d) The biggest vacuum will permit maximum heat transfer
Beware, the increased vacuum can spoil tender foods. Increased vacuums have been confirmed to impact taste, like flavor, juiciness and tenderness. Ensure to balance vacuum pressure with the above factors. Baldwin advocates for 90 – 95% vacuum and a vacuum sealing pressure of 30 to 50 mbar / 0.4 – 07 psi.
e) Avoid meals with sharp edges which may perforate the pouches
f) The Sous vide sealers used for raw meals should not again be used for ready-made RTE meals unless you clean it and sanitize it properly to prevent contamination. Another way of vacuum cleaning is by water displacement, which can be very useful for liquids.
Sous vide, just like any other cooking method, has its different requirements which must be followed to achieve high-quality and safe meals.
NB: Do not Sous vide raw Garlic