Efficacy of a carboxymethylcellulose (CMC)-based edible film with propylene glycol to control ham mite populations that infest dry cured ham

Abstract

Dry-cured hams are susceptible to ham mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), infestations during the aging process. Methyl bromide (MB) fumigation has been used to control mites from infesting hams. However, MB is an ozone depleting substance that is both expensive and scarce, so alternative control methods must be discovered. The objective of this research was to determine the efficacy of using an edible film to control or reduce mite growth and reproduction on dry-cured hams. The edible films consist of water, 1% of carboxymethylcellulose (CMC), and propylene glycol (PG), which was included at five concentrations: 0%, 5%, 10%, 15%, and 20%. The resulting films’ ability to reduce mite infestation was tested against two control groups: exposed ham cubes (negative control) and ham cubes wrapped in polyester nets (positive control) containing 40% PG, 1% carrageenan, and 1% propylene glycol alginate. Two weeks after inoculation with 20 mites, all film treatments had fewer (P < 0.05) mites than the negative control (262-mites). Film treatments with 0% (24-mites), 5% (26-mites), and 10% PG (17 mites) were effective at slowing mite reproduction, but not to the extent of the positive control (0-mites), 15% (6-mites), and 20% (1-mite) PG films as evidenced by a linear decrease in mite counts (F1 = 19.22, P < 0.0001) as PG concentration increased. Water Vapor Transmission (WVT) and Oxygen Permeability (OP) results indicated that all films exhibited substantial breathability with values ranging from 805 g m−2 day−1 to 899 g m−2 day−1 for WVT and 355 cc m−2 day−1 to 3413 cc m−2 day−1 for OP. Sensory analysis results indicated that the film treatments did not alter the sensory properties of the treated hams when compared to the untreated control. Further studies will include application of films to whole hams during aging and improved manufacturing techniques for films.