A method of inhibiting the growth of Tyrophagus putrescentiae in a pet food product includes the step of adding at least 0.3% by weight conjugated linoleic acid (CLA) to the pet food product. Specifically, adding conjugated linoleic acid to the pet food product includes the steps of adding conjugated linoleic acid to a pet food meal pre-mix, extruding the conjugated linoleic acid containing premix to form the pet food product, cutting the pet food product to size, and drying the pet food product. The method can further include the step of coating the dried, cut to size pet food product with conjugated linoleic acid.