A few things could be causing this problem. Fortunately, they’re easy to solve.
1) Use common terms instead of a specific keyword i.e. NUTS instead of TREE NUTS.
2) Differentiate your word choice for the term you wish to search i.e. sugar, glucose, fructose, high-fructose corn syrup.
3) Type the food name in the ingredients directory search short and simple. Shrinking the search can solve this problem i.e. try using the first two to three letters of a food name.