Evaluation of ingoing sodium nitrate/nitrite levels on Tyrophagus putrescentiae population growth during commercial dry-cured ham aging

Dry-cured ham is susceptible to ham mite ( Tyrophagus putrescentiae ) infestations during the aging process. Sodium nitrite and sodium nitrate are commonly used during curing to stabilize color, inhibit microbial growth, and enhance flavor. These compounds produce nitric oxide during processing, which has shown potential as a fumigant for controlling ham mites. This study evaluated whether increasing sodium nitrite and nitrate concentrations could reduce mite presence and reproduction during ham aging in a commercial dry-cured ham facility using a split-split plot experimental design. Hams (n = 20 per replication) were treated with five cure levels as the whole plot factor: 0X (no nitrite/nitrate), 1X (typical levels), 2X, 3X, and 4X increased concentrations Two types of netting were used during aging: standard uncoated control and PG-coated nets as the split-plot (containing 1% carrageenan, 1% propylene glycol alginate, and 40% propylene glycol) and aged for either 6 or 7.5 months as the split-split plot factor. Neither the nitrite level nor net type main factors impacted overall mite presence and incidence of infestation (P > 0.05). In contrast, the split-split-factor of aging time of 7.5 months had greater (P < 0.0001) infestation incidence, infestation severity, and mite coverage of the hams than 6 months of aging. In addition, mite inoculation studies on the benchtop confirmed that T. putrescentiae increased in number for all cure treatments, further substantiating that increased nitrate and nitrite concentration did not suppress mite infestations. These results indicate that these interventions alone are insufficient for Tyrophagus putrescentiae management in commercial dry-cured ham production. • Nitrite and nitrate concentrations did not affect ham mite population growth. • Mite population was greater on hams after 7.5 months than 6 months of aging. • After 7.5 months of aging, residual nitrite levels were below the limit of detection.