塩 and 砂糖: seasoning names and quantities
Name salt and sugar and check the scope of quantity expressions.
Salt as an ingredient
塩 (しお) means salt. 「スープに塩を入れました」 says that the speaker added salt to the soup; に marks where it went.
「塩を少し足してください」 requests a little more salt. 足す focuses on adding to what is already there.
Sugar and quantities
砂糖 (さとう) means sugar. 「砂糖を小さじ一杯入れます」 means adding one teaspoonful of sugar.
「砂糖は入れません」 says that sugar will not be added. It does not exclude all other ingredients.
Taste versus ingredients
「砂糖を入れすぎました」 evaluates the amount of sugar added as excessive. すぎる marks too much.
「甘いですが、砂糖は入れていません」 says it is sweet, but no sugar was added. Sweetness alone does not establish added sugar.
Does 「砂糖は入れていません」 mean the food is not sweet?
Show the answer and why
No. It only says that no sugar was added. Other ingredients may provide sweetness.