Summary of Activities at WSU in 2002

1. Improved heating block systems2. Thermal death kinetics studies (Beetles and Medflies)3. Dielectric property measurements4. Temperature uniformity study in RF systems5. Differential heating of insects in walnuts and almonds6. Improved IFAFS website design7. Cherry work at Yakima and Wenatchee

The improved heating block system developed at WSU

1. Improved WSU heating block system

• Top and bottom plate temperatures of the HBS when heated to different final temperatures at a rate of 15°C/min

1. Improved WSU heating block system (cont.)

The thermal exposure (min) in the HBS generating 100% kill of medfly(From Yoav, Israel)

Eggs 3rd larval instarTemp. (°C)Time (min) N (reps) Time (min) N (reps)

46 30 3 60 348 5 6 20 250 2 3 5 352 0.667 2 1 2

2. Thermal death kinetics studies (Medflies)

TDT curve of 5th-instar Indianmeal moth (IMM), codling moth (CM) and navel orangeworm (NOW), 3rd-instar and egg medfly

2. Thermal death kinetics studies (Medflies)

Dielectric loss factor of grapefruit () and orange () at 20°C (mean of two replicates)

3. Dielectric property measurements

Dielectric loss factor of Mexican fruit fly larvae (), Medfly larvae () and eggs () at 20°C

3. Dielectric property measurements

Dielectric loss factor of Mexican fruit fly larvae (), Medfly larvae (), and medfly egg () as a functionof temperatures at 27 and 915 MHz

27MHz

915 MHz

3. Dielectric property measurements

Dielectric loss factor of Mexican fruit fly larvae (), Medfly larvae (), and medfly egg () as a functionof temperatures at 27 and 915 MHz

27MHz

915 MHz

3. Dielectric property measurements

Dielectric loss factor (’’) of almonds and walnuts at 27 MHz as a function of temperature

3. Dielectric property measurements

Temperature uniformity setup of the 24-cups in RF system

4. Temperature uniformity study in RF systems

Schematic view of water container for temperature uniformity study (all units are in cm)

4. Temperature uniformity study in RF systems

Temperature uniformity setup of the 24-cups recorded by a data logger after RF heating

4. Temperature uniformity study in RF systems

Temperature distribution when the gap was 180mmafter 275s RF heating

4. Temperature uniformity study in RF systems

Temperature distribution for 16 cups when the gap was 180mm

4. Temperature uniformity study in RF systems

Temperature distribution for 4 cups when the gap was 180mm

4. Temperature uniformity study in RF systems

4. Temperature uniformity study in RF systems

Improved temperature uniformity in 24 cups for the new design

Walnut surface temperature distribution in a container (40X27X12cm) measured by thermal imaging

4. Temperature uniformity study in RF systems

2 layers with I=0.5A

4. Temperature uniformity study in RF systems

4. Temperature uniformity study in RF systems

Walnut temperature difference between vertical and horizontal orientations on a single layer with I=0.6A

4. Temperature uniformity study in RF systems

4. Temperature uniformity study in RF systems

Temperature profiles of walnut kernels and codling moth slurry when subjected to 27 MHz RF system

5. Differential heating of insects in walnuts

5. Differential heating of insects in walnuts

Predicted temperature difference between insects and walnuts as a function of dielectric loss factor ratios and heat transfer coefficients

915MHz 27MHz

5. Differential heating of insects in walnuts

Treatments

Heating/holding

Temperature (°C)

Mean SD Minimum

Mortality from

RF tests(%)

Mortality from

heating block tests(%)

2 min/5 min

3 min/5 min

42.6 2.5 39.0

53.3 3.6 49.0

78.6

100

10-20

71-100

Mortality comparison of 5th instar codling moth between RF treatmentson infested walnuts and heating block tests

Source: Wang et al., 2001. Postharvest Bio. Technol., 22, 29-38.

5. Differential heating of insects in walnuts

Publications in 2002Publications in 20021.1. Wang S., Tang J., Johnson J.A., Mitcham E., Hansen J.D., Hallman G., Drake S.R., Wang Y., 2002. Dielectric properties of fruits and insects as affected by temperatures. Biosystems Engineering, in review.2. Johnson J.A., Wang S. and Tang J. 2002. Thermal death kinetics of fifth-instar Plodia interpunctella (Lepidoptera: Pyralidae). Journal of Economic Entomology, Accepted.3. Wang S., Tang J., Johnson J.A., Mitcham E., Hansen J.D., Cavalieri R, Bower J., Biasi B., 2002. Process protocols based on radio frequency energy to control field and storage pests in in-shell walnuts. Postharvest Biology and Technology, 26(3): 265-273.4. Wang S., Ikediala J.N., Tang J., and Hansen J., 2002. Thermal death kinetics and heating rate effects for fifth-instar codling moths (Cydia pomonella (L.)). Journal of Stored Products Research, 38(5): 441-453.5. Wang S., Tang J., Johnson J.A. and Hansen J., 2002. Thermal death kinetics of fifth-instar navel orangeworms (Lepidoptera: Pyralidae). Journal of Stored Products Research, 38(5): 427-440.6. Ikediala J.N., Hansen J., Tang J., Drake S.R. and Wang S., 2002. Development of saline-water-immersion technique with RF energy as a postharvest treatment against codling moth in cherries. Postharvest Biology and Technology, 24(1): 25-37.

New people joined WSU group

Dr. Xinming Yin Mr. Sohan Birla

Thanks!Thanks!

Prediction models based on the efficacy study both in CA and WA cherries (from Jim) as compared with the model obtained from the HBS: log(time) = 12.41-0.23xTemp, R2=0.996

Relationship between lethal time (LT) and dead (%) of CM

by observation and kinetic study

IFAFS work in 2001-2002

-Determined the thermal death kinetics of insects-Determined the temperature dependent dielectric property-Determined the differential heating of codling moths in walnuts and almonds-Established the quality curve for cherries in water bath-Determined codling moth efficacy in cherries using water bath-Developed walnut process protocols-Started insect mortality work on med fruit flies, beetles. ??

Future IFAFS work proposed in 2003-2004

- Help industry to implement walnut process protocol- Develop process protocols for almonds and pistachios (?)- Determine the temperature uniformity of fresh fruits in RF system- Continue the insect thermal death kinetics studies