Davar Hama’amid:

• General Halachos – Exceptions [1] basar b’chalav (cheese), [2] inherently forbidden (yeast), [3] zeh v’zeh gorem, [4] remains in (immobilized enzyme, glucose isomerase, catalysts), [5] meaningful effect

• Examples – cottage cheese, vinegar, stabilizer, amylases

• Other details – kashering afterwards, chametz after Pesach, bishul akum and kitnios, whey, three ha’amados, tevillas keilim

See seforim by Rabbi Cohen at www.kashrushalacha.com