Low grade, controversial or vague ingredient we usually recommend avoiding
Propylene glycol in dog food
Propylene glycol is a synthetic compound that absorbs water and can therefore be used to keep semi-moist dog foods and treats semi-moist. It also has anti-bacterial and anti-fungal properties making it suitable as a preservative.
Although propylene glycol has been approved as safe for both humans and dogs (but not cats due to its links to the feline condition Heinz body anaemia), it remains a source of controversy. This is partly due to regular links to asthma and allergic reactions and partly because propylene glycol's other commercial uses (including car antifreeze and in de-icing aircraft) don't inspire too much confidence in dog owners.