Sometimes when I save an unfinished jar of baby food in the fridge, when I go to use it, it has become runny.  Is it still good?

--Anna

This happens if you save food that has had the spoon which you used to feed baby put back into it.  Saliva contains digestive the enzyme amylase that help to start the breakdown of food for digestion.  Amylase breaks down starch into much simpler sugar molecules.  Small amounts of saliva are transfered from the baby's mouth back into the food.  Over time the amylase breaks down the starch in the uneaten food, making it thinner.  The amount of time depends on how much contamination occurs.  Some parents report that the food gets thinner just over the time that the infant is being fed.

Because babies have developing immune systems, it is better to avoid any risk of contaminating unused food.  The easiest way to do this is to measure out only the amount that you think your infant will eat into a separate bowl, saving the rest.  Warm the food in the bowl if necessary, and feed from that.  You can always add more if baby is still hungry, using a clean spoon of course.  Discard any food that is left in the bowl.  This will prevent saliva from getting into the jar of unused food.

Heinz recommends that any opened baby food jar should be refrigerated immediately and used within 48 hours.

Baby Food Turns Run