Application of Food-Grade Ingredients to Nets for Dry Cured Hams to Control Mite Infestations

Abstract

Infestations of Tyrophagus putrescentiae (Schrank; Sarcoptiformes: Acaridae), known as the ham mite, may occur on dry cured hams during the aging process. The fumigant methyl bromide is currently used to control mite infestations, but it will eventually not be available for use since it contributes to the depletion of the ozone layer. The use of ham nets treated with xanthan gum, carrageenan, propylene glycol alginate, and propylene glycol food-grade ingredients on mite orientation to or oviposition on treated or untreated ham cubes, and mite reproduction and population growth over a 10-wk period was evaluated. Behavioral tests indicated that more than 95% of the mites oriented to the ham cubes that were wrapped in untreated nets when compared to treated nets and no eggs were laid on the latter. The reproduction assays demonstrated that there were fewer (P < 0.05) T. putrescentiae produced over a 2-wk period on ham cubes covered with both gum and propylene glycol treated nets, when compared to the untreated or gum-only treated nets over the 10-wk storage period of the experiment. Medium and high concentrations of propylene glycol treatments showed the lowest reproductive rates of mites. No more than 4 mites could be found on each of these treatments in comparison to 200 to 300 mites that were recorded on the untreated hams. This study demonstrated efficacy of using the nets treated with food-grade ingredients during ham aging to control mite infestations on a laboratory scale. Further research will be conducted to determine the effectiveness of the same treated nets on whole hams in commercial aging rooms.

Use of Lard, Food Grade Propylene Glycol, and Polysaccharides in Infused Nets to Control Tyrophagus putrescentiae (Schrank; Sarcoptiformes: Acaridae) Infestation on Dry Cured Hams

“…The net used in this study was a blend of 50% polyester and 50% cotton with high stitch density (112 loops/cm 2 ). The nets without a coating decreased the mite population since the nets reduced the meat exposure to mites and limited their actual locomotion, which is in agreement with the previous findings (Campbell et al, 2016;Zhang et al, 2017). There are a few commercially available mite-proof covers that are made from different materials, including a tightly woven cover with a pore size of 2 to 10 μm (Mahakittikun et al, 2006;, cotton fabric coated with eugenol loaded chitosan (Jarupaiboon et al, 2007), and Chitosan/Ag+-impregnated textile (Rahel et al, 2013).…”

“…The reproduction test suggested that nets containing PG reduced the mite population and the inhibitory effect was maintained over the 10-wk storage period, which is in agreement with previous findings on research conducted on gums and PG infused nets (Zhang et al, 2017). The main differences between these 2 studies were the incorporation of lard into the netting formulation and the infusion of nets with different combinations of gum, lard, and PG, which was due to the fact that coating ham cubes with lard was effective at inhibiting T. putrescentiae reproduction and has been used in commercial practice (Abbar et al, 2016a;Zhao et al, 2016).…”

“…Although there were no statistical difference among the four different treatments at each storage time point, CG + PGA + medium lard + medium PG had the fewest mites present and would be preferred for use because of the zero tolerance of mites on dry cured ham products in the United States (USDA 9 CFR301; USDA 9 CFR 416). When compared to previous research from our laboratory with XG / (CG + PGA) + medium PG infused nets (Zhang et al, 2017), the nets containing the same concentration of PG did not improve the inhibitory effect, indicating that adding lard to the formulation did not offer any added benefit.…”

“…A 2-choice behavior test was conducted according to the methods of Zhang et al (2017). One 1.3-cm ham cube covered with the control (untreated) net and another 1.3-cm ham cube covered with a treated net were offered simultaneously to the mites inside a small arena.…”

“…Since gum and propylene glycol coatings were applied to the surface of the hams, an additional processing step is necessary. Therefore, research was conducted on the effectiveness of infusing coatings into special nets that are used to hang dry cured hams on racks during aging, which revealed that gum and propylene glycol infused nets effectively inhibited mite growth and reproduction over a 10-wk storage period under laboratory conditions (Zhang et al, 2017). Since lard is used in Europe to control mites and is less costly than propylene glycol, it was hypothesized that incorporating lard into the netting solution, along with propylene glycol could control mites and reduce costs.…”