What does the cryptic crossword clue "Food in tum digested and forgotten (3,2,4)" mean?

The definition is "forgotten". The wordplay uses an anagram. anagram of FOOD + IN + TUM = OUTOFMIND; definition: "forgotten" The answer is OUTOFMIND.

Food in tum digested and forgotten (3,2,4)

Guardian Cryptic #28950 | 11 Across | 2022-12-26 flower