Performing Department
(N/A)
Non Technical Summary
This Integrated project addresses questions 1, 3, and 4 in the USDA-NIFA-ICGP-010334 Methyl Bromide Transitions program RFP in support of the dry-cured pork industry, which depends on the use of methyl bromide (MB) to control Tyrophagus putrescentiae. Previous research indicates that a carboxymethyl cellulose based film with 15-20% propylene glycol controlled mite infestations in the laboratory. Our first hypothesis is that integrating nanoparticles and reinforcing agents into carboxymethyl cellulose film will control mites in commercial plants and be more cost-efficient than current formulations. Our second hypothesis is that the use of fumigants, specifically hydrogen cyanide, can control mites in commercial ham plants without impacting sensory quality and chemical composition of the hams. Our third hypothesis is that UVC lighting can be used both as a preventive method to control mites and an intervention method to kill mites when infestations occur. Results from objectives 1, 2, and 3 will be incorporated into comprehensive integrated pest management strategies in conjunction with previous research results. Additional objectives include conducting an economic analysis on cost-benefit scenarios for proposed alternatives to methyl bromide, evaluating the overall implementation costs, and providing resources to the industry so that they can sustainably produce hams that are aged for longer than 5 months without relying on MB fumigation. Results from this project will benefit the southern dry-cured ham industry in the US, and other industries of dried specialty meats, high-value aged cheeses, and semi-moist pet foods, all of which are at risk of T. putrescentiae infestations.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
: 1. Enhance the quality of cellulosed-based biodegradable films by incorporating food-safe nanoparticles composed of either crushed eggshells, cellulose nanocrystals or zinc oxide; Treatments that control mite population growth on the benchtop will be evaluated for their effectiveness at controlling mites when scaled up to ham aging houses.2. Study the effectiveness of hydrogen cyanide (HCN) as a fumigant at varying doses, exposure temperatures, and exposure times for controlling T. putrescentiae on dry cured hams; assess the HCN residual on hams to ensure safety and efficacy.3. Evaluate the efficacy of UV-C light at controlling T. putrescentiae infestations, considering different UV-C light intensities, durations, and application methods to optimize mite control.4. Evaluate the cost-benefit scenarios for proposed alternatives to methyl bromide and evaluate the overall implementation costs.5. Collaborate with the industry to identify obstacles hindering the production of hams aged longer than 5 months; offer training and support to ham companies to overcome these barriers.
Project Methods
1. Enhance the quality of cellulosed-based biodegradable films by incorporating food-safe nanoparticles composed of either crushed eggshells, cellulose nanocrystals, or zinc oxide; investigate their industrial application to protect hams from mites.Two experiments will be conducted. In the 1st experiment, we will include food-safe eggshell nanoparticles, cellulose nanocrystals (CNC), or zinc oxide nanoparticles into biodegradable films to improve the CMC-based film's physical properties while maintaining mitecontrol efficacy. Treatments will consist of 1% CMC and eggshell nanoparticles (0%, 0.5%, 1%, 1.5%, 2%, cellulose nanocrystals (0%, 2.5%, 5%, 7.5%, 10%), and zinc oxide nanoparticles (0%, 0.5%, 1%, 1.5%, 2%). For the film preparation, all ingredients will be homogenized with a stir blade until fully solubilized. The film forming solution will be carefully cast onto a petri dish (30 mL/dish) and left to dry in an environmental chamberat 25°C and 50% relative humidity (RH). To characterize the resulting film's properties, measurements will be taken on film thickness (mm), tensile strength (MPa),Commercial trials (objective 1e). The films that exhibit favorable properties and mite controlling efficacy will be manufactured on a pilot-scale and applied to hams in three commercial aging houses, with 100 hams subjected to the optimized film treatments and 100 control hams within each aging house. The films will be applied onto the ham before it enters the aging room. The hams will be aged and monitored for 6 months. Treatments that are efficacious at controlling mites, will be evaluated with difference-from-control sensory testing?2. Study the effectiveness of hydrogen cyanide (HCN) as a fumigant at varying doses, exposure temperatures, and exposure times for controlling T. putrescentiae on dry cured hams; assess the HCN residual on hams to ensure safety and efficacy.Dose-mortality studies will be conducted to determine if HCN (BLUEFUME®, 99.9% purity from Draslovka) is efficacious at controlling mite eggs and mixed mobile stages in 24 h exposures at temperatures of 15, 25 and 30 °C. The best doses at each temperature will then be tested for different exposure times, including 6, 12 and 24 h. HCN experiments on red legged ham beetles will be conducted with similar methods. Once the most effective concentrations, exposure time and temperatures are determined for both pests, we will then study mite and beetle mortality when infesting large pieces of ham under pilot-scale commercial conditions. Additional studies will look at the levels of sorption and HCN residues over time and concentrations within ham using our established methods.. When a treatment protocol at a given temperature, concentration and exposure time are determined for HCN, and only when we know that all residual HCN has desorbed or decomposed, treated hams will be subjected to human taste panels..3. Evaluate the efficacy of UV-C light at controlling T. putrescentiae infestations, considering different UV-C light intensities, durations, and application methods for an optimized mite control.The impact of UV-C light (ton mite mortality will be assessed by varying both the distance from the UV-C light and exposure time. The experiments will be conducted inside HDPE utility armoires lined with aluminum foil on the interior. The UV-C light bulb will be positioned on the cabinet ceiling, and for safety measures, the safety switches will be wired outside of the cabinet. Adult mixed-sex mites (n=50) will be placed in a glass weighing bottle nd arranged at distances of 10, 50, 100, and 150 cm from the UV-C source for exposure durations of 5, 30, and 60 minutes at a controlled temperature of 23 ± 2 ºC and 70 ± 5% RH. A control group (total darkness) will be established to serve as a baseline. In addition, a standard LED lamp (6,000k; 9W) will be included as a regular (non-UVC) positive control. Post-exposure, mites will be set aside for 24 h after which the number of mobile mite progeny will be counted under a stereoscopeThe impact of UV-C light on mite activity will be tested using whole hams in a simulated ham aging room. Four whole hams will be suspended on metal racks, and UV-C lights will be positioned by hanging them from the ceiling at the central point where the four hams are located. The lights will be dropped to approximately 20 cm from the top of each ham. UV-C lights will also be set up on the floor, facing upward towards the hams. Mites will be placed into a 1.5 mL centrifuge tube (approximately 1,000 mites) and set to release on each whole ham sample/treatment. Following inoculation of the hams, three light source settings will be applied: ceiling UV-C lighting, a combination of ceiling and floor UV-C lighting, and total darkness (control) in three separate simulated aging rooms. Light sources will be applied for 30, 60 min, or a longer duration determined by the outcomes of the 1st experiment. Post exposure, mites on each whole ham, including those in cracks and crevices, will be monitored and counted.4. Evaluate the cost-benefit scenarios for proposed alternatives to methyl bromide and evaluate the overall implementation costs. The profitability of the alternative pest control methods, outlined in Objectives 1 through 3, will be estimated using a proportional hazard model (PHM). The study will use empirical observations of ham mite infestations from the controlled experiments to determine how variables including type of treatment, how it is applied, and its intensity, along with ambient factors such as weather influence the time varying rate of ham infestation. PHM is a flexible, regression-based modeling approach capable of incorporating effects into temporal covariates for determining the likelihood of the onset and subsequent build-up of ham mite infestation as a time dependent probability function, typically structured as a logistic or Poisson curve. Time dependent infestation curves depict the probability of a cured ham becoming infested over a time period and can be used to assess the temporal risk of ham mite infestation. This will be used to test our working hypothesis that with improved ham mite mitigation, hams can be cured for a longer duration resulting in a higher valued product.5. Collaborate with the industry to identify obstacles hindering the production of hams aged longer than 5 months; offer training and support to ham companies to overcome these barriers. Summer 2025: Members of our research team will travel to Broadbents, the Hamery, Clifty Farms, Tripps Hams, and other ham companies in Tennessee and Western Kentucky as requested. We will audit their plants and gather information on number of hams produced, production costs, margins, pest control, aging time, and integrated pest management programs. We will also discuss research projects that we will conduct at Broadbents, the Hamery, and Tripps. We will discuss what we know about controlling mites and begin the process of helping them optimize their integrated pest management plans.We will update our extension publication that is used by both ham companies and USDA-FSIS as a resource for pest control and integrated pest management.We will travel to ham companies in Tennessee, Kentucky, North Carolina, and Virginia during the Summer of 2026 (Tripps, Hamery, Broadbents, Clifty, Bentons, Goodnight Brothers, Finchville Farms, Hobes, Suncrest Farms, Sugar Grove, Colonel Bill Newsoms. Fathers). We will discuss what we know about controlling mites and begin the process of helping them optimize their integrated pest management plans if it is the first visit. If it is the 2nd visit to that plant, we will check on the progress of using their integrated pest management plan. We will also inquire about interest in conducting research in their plant and/or using some of the technology that we have developed to control mite infestations.