This is not so much a matter of health, but a matter of preference. It is perfectly safe and healthy to feed your baby food straight from the refrigerator as long as food is thoroughly cooked and has been stored properly.
Many babies have a preference for warmed foods versus cold foods, however, so if your baby refuses to eat cold food, just keep trying gradually, and chances are, she will adjust. It's not a bad idea to serve food at a variety of temperatures (cold, warmed, room temperature) since you aren't always able to warm foods on outings, and may have to pop a jar out of the diaper bag or ice chest when your baby is hungry.
When in doubt about whether or not to warm a certain food, use your own food as a guideline. If you typically serve green beans warm, for instance, serve them to your baby warm. If your family eats ham as a cold cut but seldom cooked (like a holiday ham) then serve your baby cold ham.
Uneven microwave heating is another reason you might want to serve jarred and other food straight from the cabinet or fridge. Microwaves create hot spots in food that can burn your baby's mouth. Be sure to stir food thoroughly and test the temperature of food before feeding when using this method of heating.
If you've ever fed your baby straight from the jar and put the leftover amount back in the refrigerator, you may have noticed it soon becomes thin and watery. This is because the food mixes with your baby's saliva. Saliva contains enzymes which break down food and can allow bacterial growth. It's best to put small amounts of food in a bowl for feeding if you know your baby won't be eating the entire jar.
Remember, too, jarred foods that are commercially prepared are safe for feeding as long as the vacuum seal remains. Before you open the jar, always test the lid to make sure it doesn't make a popping noise when pressed, and listen for the sound of air entering the jar when you do open the lid. Once opened, food should be refrigerated and will keep for two to three days.
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