glycerin

If a company uses glycerin in its product, e.g. in toothpaste or mouthwash, can we use it if according to the company any animal by-product used is chemically altered during manufacturing and no longer resembles the original substance by the time it's added to the product? The company says that they have no way to telling what their source of glycerin is. It could be vegetable based or animal based, in which case it could be either pork or beef. So am I allowed to use such toothpaste or mouthwash which contain glycerin?