Low grade, controversial or vague ingredient we usually recommend avoiding
Natural flavourings in dog food
The term natural flavouring can be used for any extract from any food whose significant function is flavouring rather than nutritional. This is clearly very broad and could refer to anything from herbs or meat meals to more questionable ingredients like digest.
In dry pet foods, natural flavourings sometimes refers to a combination of fresh meat and oils which is sprayed on to the food in the final stages of manufacturing.
If you are at all unsure about the ingredients of your dog food, it is always best to contact the manufacturer directly.