Source: KANSAS STATE UNIV submitted to
DEVELOPING IPM WITH METHYL BROMIDE ALTERNATIVES FOR PROTECTING SOUTHERN DRY-CURED HAMS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
Reporting Frequency
Annual
Accession No.
1000685
Grant No.
2013-51102-21016
Project No.
KS602842
Proposal No.
2013-04494
Multistate No.
(N/A)
Program Code
112.C
Project Start Date
Sep 1, 2013
Project End Date
Aug 31, 2016
Grant Year
2013
Project Director
Phillips, T. W.
Recipient Organization
KANSAS STATE UNIV
(N/A)
MANHATTAN,KS 66506
Performing Department
Entomology
Non Technical Summary
This multi-institutional and multi-disciplinary proposal is for an Integrated Project to both conduct research into integrated pest management (IPM) for southern dry cured hams that include methyl bromide (MB) alternatives for controlling the ham mite, and conduct Extension and Education for the country ham and pest control industries. Country ham producers are one of three groups with a proposed CUE for MB in year 2015 in the US. This work is highly relevant because no adequate substitute for MB has been found for controlling ham mites to date. Sulfuryl fluoride did not control mites in past work, but this project will study higher temperatures to improve efficacy. Phosphine gas can kill all mite stages within label concentrations, but this gas is damages electrical components. New phosphine formulations with less corrosive potential combined with methods to protect electrical infrastructure will be studied. The fumigant MITC will be studied for mite control and effects on ham quality. Food-safe ham coatings that prevent mite infestation will be studied, as will chemical pesticide sprays to deter mites in buildings. Mite traps will monitor pest populations to promote informed decisions on pest control. This project will benefit the southern dry-cured ham industry in the US, plus all dried specialty meat and the aged cheese industries. An economic analysis of costs, benefits and risks for IPM practices in the country ham industry will be conducted. We will develop educational materials and deliver extension programs for producers pest control operators to implement dried ham IPM programs.
Animal Health Component
20%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2163120106060%
5033120113040%
Goals / Objectives
This multi-institutional and multi-disciplinary proposal is for an Integrated Project to both conduct research into integrated pest management (IPM) for southern dry cured hams that include methyl bromide (MB) alternatives for controlling the ham mite, and conduct Extension and Education for the country ham and pest control industries. Country ham producers are one of three groups with a proposed CUE for MB in year 2015 in the US. This work is highly relevant because no adequate substitute for MB has been found for controlling ham mites to date. Sulfuryl fluoride did not control mites in past work, but this project will study higher temperatures to improve efficacy. Phosphine gas can kill all mite stages within label concentrations, but this gas is damages electrical components. New phosphine formulations with less corrosive potential combined with methods to protect electrical infrastructure will be studied. The fumigant MITC will be studied for mite control and effects on ham quality. Food-safe ham coatings that prevent mite infestation will be studied, as will chemical pesticide sprays to deter mites in buildings. Mite traps will monitor pest populations to promote informed decisions on pest control.
Project Methods
Toxicity of SF at high temperatures against ham mites: Laboratory dose-response toxicity bioassays will be conducted with SF and mites. One day old mite eggs, mid-sized nymphs and adults will be fumigated in groups of at least 20 in ventilated vials containing moist mite diet. At least three replicates of each life stage will be assayed per concentration. The same concentrations as presented in Fig. 2 will be applied to 3.7 l sealed fumigation jars for 48 hr exposure periods. Concentrations in individual jars will be determined by quantitative GC-Mass Spectrometry. Separate experiments will be conducted at the following three temperatures: 25o C, 30o C and 35o C. Mite bioassays will be held for up to one week after fumigation to confirm mortality of all treated mites. A temperature of 35o C is perhaps the highest the country hams could tolerate for short period under fumigation. Fluoride Ion Analysis: The EPA has set minimum food tolerance levels for fluoride ion in meat at 20 ppm. We will measure residues at these levels by taking ground ham samples (5g) and mix them with 50 mL of water in a beaker, stirring for 1 hr prior to the addition of 50 mL Total Ionic Strength Adjustment Buffer (TISAB) to the mixture. The Accumet Fluoride Ion Combination Glass Electrode (Fisher Scientific Inc. Hampton, NH) will be used to calculate fluoride ion concentration. The Accumet Research AR-25 Dual Channel pH/Ion Meter (Fisher Scientific Inc. Hampton, NH) will be used to quantify fluoride concentration. Determination of Sulfuryl Fluoride (SF) gas in ham: The food tolerance level of free SF gas in meat is set at 0.01 ppm. Two concentrations of SF gas will be purchased from Scott-Marrin, Inc. Riverside, CA. The SF gas will be transferred to 1 L Tedlar bags (Supelco, Bellefonte, PA) by using a regulator and a small diameter thin rubber hose pipe. These standards will be used to verify the presence of SF as well as to conduct standard curves when SF is detected in hams that were fumigated with sulfuryl fluoride. Toxicity of MITC against ham mites: Laboratory bioassays of methyl isothiocyanate, MITC, as a toxic fumigant against ham mite life stages will be conducted with similar methods described above for SF. MITC is the gas generated from the salt metam sodium when it is exposed to air and water. Metam sodium is a currently registered soil fumigant in the US; it is a MB alternative applied to soil prior to planting high-value horticultural crops. MITC occurs naturally with a collection of similar volatiles released by plants in the family Brassicaceae such as cabbage and broccoli. Preliminary experiments at KSU have determined that relatively low concentrations of MITC, about 1.0 mg/l, for 24 hrs at 25o C is very effective at killing eggs, larvae, pupae and adults of all stored product insects tested and also is toxic to ham mite eggs and adults. This activity of MITC requires only 1 day, instead of two, to kill arthropods, and neither a high concentration or a high temperature are needed. Determination of MITC concentration in hams: MITC will be diluted to 10 pg/ml with methylene chloride and then stabilized with acetone to reach final concentrations of MITC that will be used for a standard curve (R2>0.99) prior to sample analysis. Samples will be prepared through homogenization with salt and dissolving in methylene chloride and acetone. Samples will then be extracted with a charcoal tube. After extraction, the samples will be desorbed into a capped test tube and injected into a gas chromatograph-mass spectrometer with the following operating conditions: injector temperature of 210?C, column flow rate of 4 mL/min, initial oven temperature of 40?C for 4 min hold time with 12?C/min ramp rate to 160?C and then ramp to 240 C at 40 C and hold at 240 C for 1 min, and a pressure of 10 psi and equilibration time of 0.25 min. Extraction of volatile compounds by SPME for GC-pFPD, GC-MS and GC-FID: The method that will be used for the extraction of headspace volatile compounds by SPME will be obtained from previous studies (Sekhon et al., 2010, Pham et al., 2008). Homogenized ham samples (10g) will be transferred to pre cleaned 40 ml amber glass vials (O.D. 28 x 98 mm height, Supelco, Bellefonte, PA) with propylene screw caps and Teflon faced silicone septums (O.D. 22 mm diameter x 31.75 mm thickness, Supelco, Bellefonte, PA) with 1.5 g sodium chloride salt equilibrated at 50?C for 30 min. The StableFlex 1 cm -50/30μm three phase (DVB/CAR/PDMS) SPME fiber (1 cm-50/30 μm StableFlex Divinylbenzene (DVB)/ CarboxenTM (Car)/ Polydimethylsiloxane (PDMS),Supelco, Bellefonte, PA) will be inserted into the vial to extract the volatile compounds that are present in the headspace. Gas Chromatography/Pulsed Flame Photometric Detector (GC-pFPD): The GC-pFPD analysis will be carried out using a Varian CP-3800 (Varian Inc., Walnut Creek, CA) gas chromatograph equipped with a DB-5 column (30m long x 0.53 mm i.d., 0.25 μm film thickness, J & W Scientific, Folsom, CA.) and a flame photometric detector. Operating conditions will be as follows for the: injector temperature of 225?C, column flow rate of 4 mL/min, initial oven temperature of 35?C for 4 min hold time with 14?C/min ramp rate to 250?C, and a pressure of 10 psi and equilibration time of 0.25 min. The detector temp will be 250?C, and the total running time will be 12.36 min. Ultra high purity helium (Airgas, West Point, MS) will be used as the carrier gas for the experiment. Analysis of each sample will be repeated in triplicate to ensure reproducibility of the results. Development of Food Grade Coatings: Previous research in the laboratories of Phillips and Schilling has demonstrated that a concentration of 50 % or higher propylene glycol in water coated onto the surface of country ham pieces will have the ability to control mite infestations for 14 days at room temperature (Figs 3 and 4, above). In addition, lard and Butylated HydroxyToluene (BHT) also demonstrated the ability to control mite growth, even though they are not as effective as propylene glycol. These chemicals are consider "GRAS", or generally regarded as safe, food additives and are commonly used in processed food products. Cylinderized phosphine: Up to now our field or simulated field fumigations with phosphine gas utilized the phosphide salt magnesium phosphide, which generates hydrogen phosphide gas over time as it reacts with water vapor in the atmosphere. Phosphide salts are the most commonly used formulations for applying phosphine gas, but they have some qualities that may be drawbacks for country ham applications. Phosphide salts must undergo reaction with water vapor to generate phosphine gas, thus there is a lag time from the time of application to the time at which the target concentration is reached. For phosphine we will target 2000 ppm to be reached and maintained for 48 hrs at a temperature of at least 30o C. Bioassays with live mites and corrosion tests of copper tubing or low cost electronic calculators will be placed in the fumigated rooms. If SF is used at a ham facility as a result of a good laboratory result at high temperatures in Objective 1, then we will do at least one commercial fumigation at such a facility for 48 hrs at 35o C and at a gas concentration of 25 mg/l or less. Mite Sampling and Trapping. We will sample hams and ham production aging environments to determine mite density and correlate these direct population measurement with capture numbers in mite traps to develop predictive models of mite population size based on trap count. Our KSU mite trap performs very well for detecting and monitoring ham mites in all habitats in which we have tested them so far.