The term "food grade" in reference to a material, such as the aluminum
foil that is on the top of yogurt containers, does not reference whether
it is edible or not, but rather that it can be used in contact with food.
The article "Food Storage In The Home" by Charlotte P. Brennand, PhD,
and Deloy G. Hendricks, contains a description of a food grade material.
"A food-grade container is one that will not transfer non-food chemicals
into the food and contains no chemicals which would be hazardous to human
As for the edibility of the aluminum foil lid of a yogurt container, it
just isn't digestible. Although the following are references to dogs
and cats, animals are pretty much animals.
"Dealing with Your Dog's Digestive Dilemmas" adapted From: "Dog Health &
Nutrition For Dummies" from the Dummies.com web site talks of this.
"Another common reason for vomiting is the condition that veterinarians
affectionately call garbage gut. Most dogs are pretty indiscriminate
about what they eat, and they can develop gastritis (inflammation of the
stomach) from eating garbage, especially if they consume a few indigestible
ingredients such as aluminum foil along with the edibles. A dog with garbage
gut often vomits several hours after eating, after the stomach has made a
good try at digesting the indigestible. After the dog regurgitates the
offending material, she's usually fine."
The Spring 2004 issue of "Yolo Tails," News from the Yolo County SPCA
("Society for the Prevention of Cruelty to Animals") comes right to point.
"Foil is indigestible and can block intestines."
Earlier in the same newsletter, they talk of other potential health issues.
"Plastic wrap and foil candy wrappers can choke your pet, cut the inside
of his esophagus or stomach, or block intestines."
If your guinea pig acted like most guinea pigs I have seen, it nibbled at
the aluminum foil lid, and only bit off small pieces. As the foil that
covers these containers is pretty thin, it is also pretty malleable, so the
potential health hazards might be reduced. As the old joke goes, the foil
will (hopefully) work itself out in the end. Good luck!
If you need any clarification, please feel free to ask.
Google search on: foil indigestible
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