Friday, 4 January 2013

Cold Turkey Anyone? Our Guide to Cooling, Freezing and Thawing

With the festive season done and dusted and another opportunity to turn over a new leaf in the New Year we look forward to successful business, to keeping resolutions and fresh starts. And whilst the weather outside is frightful we ask you to bear in mind good housekeeping and keeping cold things cold with our guide to cooling, freezing and thawing of food.

The basic rule of good practice is to cut down the amount of time high risk food is kept in the danger zone (between 5°C and 63°C). Food will be in the Danger Zone if left in ambient temperatures, (room temperature) plus food passes through the Danger Zone while it is being cooled, thawed or heated.

Here’s a checklist of must-do’s to ensure you don’t get a chilling review from a customer:
  • Check temperatures as food is delivered to your workplace (use a probe thermometer)
  • Refrigerate raw, highly perishable & high risk foods immediately after delivery
  • Keep food refrigerated until it is needed for preparation or serving.
  • Cool food rapidly, so that food spends as little time as possible in the Danger Zone.
  • Thaw frozen food in a refrigerator so that the outside temperature of the food cannot reach Danger Zone temperatures whilst the inside is still frozen.

Cooling Hot Food

Hot food passes through the Danger Zone temperature as it cools, so the temperature must be reduced as quickly as possible.

The best way to cool food is in a blast chiller, as this shortens the time the food spends in the Danger Zone. However, most small businesses may not have a blast chiller. Therefore you should aim to cool the food to 5°C or colder within 90 minutes and then refrigerate it. Food kept at 0°c to 5°c will prevent or slow down bacterial multiplication. All high risk and perishable foods must be refrigerated.

Before refrigerating, transfer the food to a clean, cold container, make sure it is covered and move it to the coolest part of the food area. Never place hot food in the refrigerator as this will raise the temperature of the fridge and cause condensation that could contaminate other food. Whenever possible use large shallow trays and pans for cooling food in liquid, because the large surface area helps to accelerate the cooling process.
Remove cooked meat joints and whole chickens from their juices before placing them in a clean container with enough space to allow air to circulate. Cover and protect all food from contamination while it is cooling.

It’s important to:
  • Use separate refrigerators or cold stores if at all possible. This way you can store raw foods such as meat and poultry in one fridge and high risk foods such as dairy products and cooked meats in the other.
  • Stack shelves neatly so you can easily check the stock. Allow enough room around food for air to circulate, this way, the fridge will be able to operate more efficiently and reach its target temperature quickly.
  • Not leave refrigerator doors open any longer than necessary as the temperature inside the fridge will rise and the food may be exposed to the Danger Zone.
  • Not put hot food in a refrigerator as this will raise the temperature inside and may cause condensation which can cause cross-contamination by dripping onto other food.

Thawing Frozen Food

Raw foods such as meat and poultry must be completely thawed before cooking. Inadequate thawing can result in food poisoning.

Here’s a quick guide to thawing frozen food:
  • If ice remains in poultry or meat, the surface of the food may cook while the inside temperature remains in the Danger Zone.
  • Wherever possible thawing should take place in a thawing cabinet or in a refrigerator set aside for this purpose.
  • If you have to use a fridge, always put the food you are thawing on the bottom shelf to prevent the juices dripping onto other foods and cross-contaminating them.
  • Place the food in a container that will hold the thawing juices, without overflowing or dripping.
  • Microwave ovens can be useful for thawing, provided that the manufacturer's instructions are followed carefully.
  • Always plan your work so as to give food ample time to defrost completely.
  • Cover food as it is thawing to prevent contamination
  • Never re-freeze thawed food, because the food may have been sufficiently warm for long enough to allow bacteria to resume multiplication.

Frozen Storage

Foods kept in freezers will keep bacteria dormant at temperatures of -18°C or below so they cannot multiply. Just as you would in a fridge; place raw foods below high risk foods to avoid any risk of contamination. Place stock with a shorter shelf life in front of stock with a longer shelf life.  Keep food in the suppliers packaging if it is clean and undamaged and always re-seal opened packaging.

If food needs to be re-wrapped label it clearly and include the date it was frozen. Do not put unwrapped food in the freezer as it could become contaminated, cause contamination or be damaged by freezer burn.
So by following simple rules you don’t need to get in a cold sweat over chilling, thawing and freezing procedures.