Chemical and physical methods for the control of the mite Acarus farris on Cabrales cheese

The astigmatid mite Acarus farris is the main species of mite infesting Cabrales cheese, a traditional Spanish product. This species may reach population density levels of 260 mobile mites/cm2, resulting in high economic losses. Different chemical and physical methods that were able to control this pest without affecting the organoleptic quality of Cabrales cheese were tested. The efficacy of four short-chain fatty acids (caproic, caprylic, pelargonic and capric) and two sugar alcohols (ribitol and xylitol) were tested under laboratory conditions against mobile stages of A. farris. Only pelargonic acid significantly increased mortality in comparison with controls (63.4 vs. 26.1%, respectively). Additionally, the contact effect of the monoterpene eucalyptol was assessed in cheese maturing rooms at doses of 2.5 and 1.25 μl/cm2. The first dose effectively controlled A. farris, but its application negatively affected the organoleptic values of the treated cheeses. Finally, the application of the waxy food coating READOM CBR to Cabrales cheeses in maturing rooms, kept the mite population low but negatively modified the external appearance of the cheese, an important quality parameter.The physical approach was based on lowering the usual cheese maturing temperature (15 °C) to 6, 4 or 2 °C. As temperature decreased, A. farris density was drastically reduced from 174 ± 33 mites/cm2 at the control temperature (15 °C) to 14, 11 and 1 mites/cm2 for 6, 4 and 2 °C, respectively, though the maturing time was considerably extended. The feasibility of both chemical and physical methods for the control of A. farris is discussed.