The steady amount of produce in your guinea pig's diet means that you need to be conscientious about removing uneaten fruits, veggies, and other perishable foods before they spoil.
Always introduce new foods slowly and patiently
Care & Feeding Instructions: When introducing a guinea pig to a new food, begin with a mixture of the old and new foods, gradually increasing the amount of the new food over a 7 to 10 day period. This will prevent digestive upsets as well as allowing your pet to adjust to something new. The following feeding amounts can be used as a starting point and should be adjusted to maintain a guinea pig's proper weight. The portions shown below are for one rabbit. Adjust the amount if additional guinea pigs are fed. Daily feeding amount guinea pig: 1/4-1/2 cup. Other keys to keeping a healthy guinea pig. Keeping clean water is an essential component of a good pet care program. Clean cage at least weekly. Guinea pigs must have a proper amount of vitamin C in their diets so timothy complete is packed with long-lasting vitamin C. Storage Instructions: For maximum freshness, store in a cool, dry location. Reseal between each use. Refrigerate or freeze for extended storage.
Guinea Pig Feeding : The Humane Society of the United States
There is no reason to mix critical care with baby food or to feed it unless the pig is not eating. There very, very few baby foods suitable for guinea pigs.
Food - guinea pig care and gifts | CavyMadness