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Cooling and Reheating


May 18, 2011

Chef Mic: The Love/Hate Relationship of Food Safety

When a candy bar melted in the pocket of Dr. Percy Spencer during an experiment, a revolution in food prep began.  Shortly after, the microwave was born.  By the mid-1970s, sales of the illustrious unit outdid that of the tradition gas range, and today, almost every household in the country has one as well as most restaurants. 

While microwaves have earned their place in food preparation, I have to admit that I am a little paranoid of them.  I only trust them to heat my coffee and make my popcorn; however, if one understands their limitations and knows how to use them safely, they can be a valuable tool.  Anyone who has heated a hot pocket in Chef Mic (a lovely name dubbed by a friend of mine in the food service industry) knows exactly what I am talking about.  The meatball on one end is still frozen while the meatball on the other end is temp of the sun.  Due to the way microwaves work, they often heat unevenly leaving "cold spots" that will not reach a high enough temperature to kill dangerous bacteria.  These spots could lead to foodborne illness. 

Take the following precautions to insure safety when you use the microwave:

1) Spread the food evenly on the plate if a solid food. 
2) Cover with plastic wrap with a corner vented.  This will trap heat inside the dish and help get the food to temperature while allowing some steam to escape.
3) Microwave at the appropriate power.  It is recommended that you use decreased or half-power for large quantities, frozen, or thick foods.  This is important because microwaves only heat the outer few inches.  The outside will burn or scorch while the inside does not get to temperature.  A lower power for a longer time allows the outside to heat without decreased quality, and give it time to heat the middle through conduction. 
4) Stir the food and heat again.  Continue to do this step until you feel the food is hot enough to temp.
5) Remove, stir and then temp the food with a sanitized thermometer in several spots.  Temp sections in the middle as well as the inside.  If each section temped is above 165F, let the food sit completely covered for at least two minutes.  This "sit time" allows the temperature distribute throughout the food, and believe it or not, allow the temperature of the food to increase even more!
6) After letting the food sit, temp it again to ensure the food stayed 165F or more, and immediately serve it or move to a hot hold unit.

Keep in mind that microwave safety is very important, especially when cooking meats from a raw state or when reheating potentially hazardous foods.  No matter what meat you are cooking, or item you are reheating, the Montana Food Rules, require licensed food establishments to reach 165F, and we at MCCHD recommend that those at home use this temperature as well.  Never skimp on stirring and rotating, and never miss taking a temperature!  Thermometers are the only way you can be sure you've done it right!

Topics:
Temperature/Time; Cooling/Reheating
July 19, 2010

Cool Before Sealing

What?  I know.  Catchy title.  But what does it mean?
Well, simply put, if you heat food up, put it into a container and place it into the fridge for later use, you must ensure that it cools properly-- and chances are if you seal it in a plastic bucket or glass jar, it's not going to.  I have noticed a lot of products lately, especially at Temporary Food Service booths, that have been improperly cooled and sealed prior to the event-- baked beans heated in advance to mix in the spices, salsa products that were heated prior to packaging without a controlled acidified process and meat sauces made by the gallon.  All of these products need to be properly cooled before sealing them in their plastic buckets and mason jars and taken to events. 

Why?  Easy. We all know that food cannot be left in the Temperature Danger Zone or TDZ (41F to 135F) for very long.  Reason being, bacteria that can cause foodborne illness double every twenty minutes in that temperature range, and some bacteria, like the ones associated with improper cooling, can even produce toxins.  Since food must pass through the TDZ during cooling there is a risk that it will spend too much time out of temperature.  Most often proper cooling is thwarted by the preparer when they seal heated foods in glass and plastic containers, preventing the product from releasing heat.  What they need to do is help the product breathe and release heat. 

So how we do that?

1) Use shallow dishes like hotel pans or sheets pans to cool food.  Only place food in the dish 1-2" deep, put into the refrigerator and stir.
2) Use ice baths.  Fill a prep sink with cool water and ice, set the kettle or dish into the sink, making sure the ice/water mixture does not spill over the edge and into the food.  Stir often.
3) Put ice into the food product to assist cooling.
4) Use smaller portion sizes.  The more surface area to volume ratio you have, the better off you are.  It's much easier to cool a bowl of soup than the whole kettle!
5) Take temperatures and stir often to make sure you hit the required cooling parameters and never combine foods into large or sealed containers until they are completely and properly cooled.

Cooling Parameters:
One Step Method--
From 135F to 41F within four hours.

Two Step Method--
From 135F to 70F within two hours.  From 70F to 41F four hours after that.

Topics:
Cooling/Reheating; Temporary and Outdoor Events
Have a question or comment on one of our blog entries?  Have a question you would like addressed?  Contact ajohnson@co.missoula.mt.us.

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