Orientation behavior of the stored-product mite, Tyrophagus putrescentiae (Shrank) towards meat products with various treatments

Tyrophagus putrescentiae (Shrank) (Acari: Acaridae), a major pest of cured ham, has been controlled using methyl bromide. Methyl bromide is being banned as an ozone-depletor, so alternative controls must be developed. Two-choice behavioral tests were set up in arenas to determine the preference of the mite to ham cubes of different moisture contents (0, 24 and 48 hour air-dried). Mites were also exposed to ham cubes treated with water (control), food based-oils of soybean, corn, canola, and olive, and food preservatives such as glycerol, propylene glycol, 10% sodium sorbate, 10% potassium sorbate, 10% calcium sorbate, 10% potassium propionate, and 10% calcium propionate for two hours. Studies were carried out in total darkness at 27±2 °C and 70% RH. There was significant difference between the 24 hour dried ham and zero-hour dried (control) ham (P < 0.05) with greater number of mites orienting towards and settling on the zero- hour dried ham cubes. Also, a significantly greater number of mites preferred zero-hour dried (control) ham to 48 hour dried ham. Fewer mites oriented to the 48-hour dried ham than to the 24-hour dried ham. Differences may be due to the lower moisture content of the 24- and 48- hour dried ham. All the food-based oils and preservatives tested were significantly different from the control (P < 0.05), exhibiting Response Index (percentage of mites on the treated ham cubes) Values significantly less than 50. Thus the treated ham pieces were non-preferred and show potential for protecting hams from mites in practice.