It is even more common to see preservatives added to dishes. Nutritionists lament that many private contractors that prepare food for a large number of schools from a central location ignore regulations stating that foods are not to be prepared before 9 a.m. (because food begins to spoil after four hours at room temperature).
營養師透露，不少公辦民營的外包式「群組廚房」，並沒有遵守早上 9 點以後才能出菜的規定（因食物在室溫下存放 4 小時以上就會開始敗壞）。