。
She's picky about food.
Literal
She [topic-は] food [possessive-の] preferences [subject-が] fussy.
好みがうるさい combines 好み (このみ, 'preferences, tastes') with うるさい ('fussy, particular, noisy'). When うるさい describes someone's standards rather than volume, it means 'picky, exacting.' This usage extends beyond food: 服にうるさい ('picky about clothes'), 言葉にうるさい ('particular about language').