Phosphine fumigation and residues in dry-cured ham in commercial applications

• A method was developed to analyze for residual phosphine in dry-cured ham.
• Phosphine gas was not detected in hams 4 days post-fumigation.
• Phosphine gas had limited success at controlling ham mites under commercial conditions.
• Phosphine gas was highly corrosive to copper electric components.

Dry-cured hams often become infested with ham mites (Tyrophagus putrescentiae) during the aging process. Methyl bromide has been used to fumigate dry cured ham plants and is the only available fumigant that is effective at controlling ham mite infestations. However, methyl bromide will eventually be phased out of all industries. This research was designed to determine the efficacy of phosphine fumigation at controlling ham mites and red-legged beetles and any impact of phosphine fumigation on the sensory quality and safety of dry cured hams. Fumigation trials were conducted in simulated ham aging houses and commercial ham aging houses. Mite postembryonic mortality was 99.8% in the simulated aging houses and > 99.9% in commercial aging houses three weeks post fumigation. Sensory tests with trained panelists indicated that there were no detectable differences (P > 0.05) between phosphine fumigated and control hams. In addition, residual phosphine concentration was below the legal limit of 0.01 ppm in ham slices that were taken from phosphine fumigated hams.