Effectiveness of nets treated with food-grade coatings following various drying methods for controlling mite growth on dry-cured hams

Tyrophagus putrescentiae (Schrank), commonly referred to as the ham mite, may infest dry-cured pork during aging. Food-grade propylene glycol (PG) coated ham nets inhibit mite growth and reproduction, but there are application challenges, including shipping costs and handling. Therefore, the objective of this research aimed was to determine if the food-grade coating treated ham nets were still effective at controlling mite growth after drying. Using previously developed methods, polyester nets were coated with a food-grade solution of 40% PG, 1% propylene glycol alginate, and 1% carrageenan. Six treatments were evaluated: no net (NC), coated and wet net (WC), uncoated net (UC), oven-dried for 7 min at 93.3 °C (OD7m), oven-dried for 20 min at 93.3 °C (OD20m), and counter-dried at 22-23 °C for 24 h (CD24h). Ham cubes (2.5cm × 2.5cm × 2.5 cm) were wrapped in the nets (n = 5/trt) and inoculated with 20 adult mites. The cubes were stored in ventilated jars at 25 °C and 70% relative humidity for 14 d. Mites on each ham cube were counted after the 14 d incubation period. A randomized complete block design was used to determine if differences existed (P ≤ 0.05) among treatments. Duncan's multiple range test was used to separate treatment means when differences existed. The OD7m, CD24h, and WC treatments had fewer mites (P ≤ 0.05) than the OD20m and UC treatments; the C treatment had the greatest (P ≤ 0.05) mite count. The OD7m and CD24h treatments lost 37.3% and 36.5% of their starting weights, respectively, while OD20m lost 72.0%. The greater loss (P ≤ 0.05) for the OD20m treatment may have affected the treatment's efficacy. In addition, drying coated nets did not affect the mechanical quality of nets nor the sensory quality of hams when they were wrapped in dried coated nets.