The following ingredients should be avoided by all Muslims:

 

Lard         :    All forms should be avoided except for Plant/Microbial/Synthetic.                       The fat of pigs or hogs melted down and made clear. Lard is made especially                       of the  internal fat of the abdomen and is used in cooking.                        (Source: World Book Dictionary Millennium 2000 Edition)

Gelatin      :   An odorless, tasteless, protein substance like glue or jelly obtained by boiling the                      bones, hoofs, and other waste parts of animals. It dissolves easily in hot water                      and is used in making jellied salads and desserts, camera film, and glue.                      (Source: World Book Dictionary Millennium 2000 Edition)

Pepsin       :   An enzyme in the gastric juice of the stomach that helps to digest meat,                      eggs, cheese, and other proteins.                      (Source: World Book Dictionary Millennium 2000 Edition)

Enzymes   :   Microbial Enzymes are okay                      A protein substance produced in living cells, that influences a chemical reaction                      within  a plant Or animal without being changed itself an organic catalyst.                      Enzymes help break down food so that it can be digested. Pepsin is an enzyme.                     (Source: World Book Dictionary Millennium 2000 Edition)

Rennet      :   Substance containing rennin, obtained from the stomach of a calf or other                      ruminant, used for curdling milk in making cheese and junket.                      (Source: World Book Dictionary Millennium 2000 Edition)

Whey        :   Should be avoided unless it is made using vegetables.                      The watery part of milk that separates from the curd when milk sours and                      becomes coagulated or when cheese is made.                      (Source: World Book Dictionary Millennium 2000 Edition)                      Rennet is used to curd the milk. Whey should be avoided because the                      rennet used to curd the milk could be from a haram or non-Zabihah animal.

Vanilla Extract : A flavoring extract made from the vanilla bean and used in                           candy, ice cream, and perfumes.                           (Source: World Book Dictionary Millennium 2000 Edition)                           The flavor extracted from vanilla beans is soluble only in alcohol.                           Documentation from a distributor of vanilla extract shows that the                          ingredient contains over 50% alcohol.