evaluating pics for groundnut
DESCRIPTION
Evaluating PICS for Groundnut. H. Sudini 1 , C.L.L. Gowda 1 , V. Margam 2 and L.L. Murdock 3. 1 International Crops Research Institute for the Semi-Arid Tropics, Patancheru, India 2 Computational Biosciences Research Center, KAUST, Saudi Arabia - PowerPoint PPT PresentationTRANSCRIPT
Evaluating PICS for Groundnut
H. Sudini 1, C.L.L. Gowda 1, V. Margam 2 and L.L. Murdock 3
1 International Crops Research Institute for the Semi-Arid Tropics, Patancheru, India
2 Computational Biosciences Research Center, KAUST, Saudi Arabia3 Dept. of Entomology, Purdue University, West Lafayette, IN, USA
Purdue Improved Crop Storage Workshop, April 10-12, 2012, Accra, Ghana
Groundnut (Arachis hypogaea)
Groundnut (Peanut) is an important food legume in semi-arid tropical countries
Grown in more than 100 countriesIndia alone ~5.6 M tons (FAOSTAT
2010)Important post-harvest constraints
Aflatoxin contaminationBruchid infestation
• Mycotoxins, the secondary metabolites of Aspergillus, Fusarium, and Penicillium, are among the most common natural contaminants of foods and feeds
Mycotoxins
Factors affecting aflatoxin contamination during post-harvest
Abiotic•Water activity•Temperature•Gas composition
Biotic•Storage insect pests
Groundnut Bruchid
Caryedon serratus (olivier) is the most important storage pest
The adult is reddish brown beetleFemale beetle attaches its eggs to the pod wallThe eggs are small and milky-white in color and
hatch about 8 daysGrubs are stout and fleshy and they complete
four instars in about 23 daysFull grown grub makes a round hole on the pod
wall through which it leaves the pod and pupate at the bottom. Pupal period ranges between 14 and 16 days
Grubs bore through the pod wall, feed on the internal contents of the seed and make them hollow
EggPupa
Linkage
Venu Margam from Purdue visited ICRISAT during late 2010
Capacity building Introduced to Dr. MurdockDeveloped a proposal to test the
efficacy of PICS bags for Groundnut storage
Subsequently Purdue provided financial assistance
PICS experiment on Groundnut @ ICRISAT
Important underlying goalsTo check bruchid damage levelsTo monitor aflatoxin contamination levelsTo test seed viability (Germination)
Two independent experiments with different moisture levelsIst Batch experiment- 4 months storageApproximately 8% MC
Methodology
•A generalized experiment with 3 replications
•25kg unshelled pods•5% Groundnut Bruchid infestation (approximately 1.25 kg of infested pods)
•On an average 6-8 adults per every 100 grams of pod
Methodology
Observations recorded onGas composition at
regular intervals (O2/CO2 Analyzer-Mocon)
Germination percentage (seed viability before and after the experiment)
Aflatoxin levels before and after the experiment (indirect competitive ELISA)
Sample Processing Representative sample 100 g of subsample
made into powder 20g of powder added to
100ml of 70% methanol Shake it for 30 min. After filtration, the
methanol extracts were stored at 4oC till they used
ELISA Plate Design
• Read the plate at 405 nm• Higher toxin concentration confer light color that leads to
low OD value and vice versa
Results-Gas composition
O2 Level CO2 Level
Infested PICS 1 9.22 7.04PICS 2 12.17 5.65PICS 3 6.79 8.27Gunny Bag 1 20.18 0.15Gunny Bag 2 20.31 0.13Gunny Bag 3 20.30 0.17
Uninfested PICS 4 6.15 8.84PICS 5 5.41 8.32PICS 6 10.80 4.94Gunny Bag 4 20.07 0.15Gunny Bag 5 20.13 0.13Gunny Bag 6 20.19 0.12
Results-Insect damage levels after opening the bagsRep 1 Rep 2 Rep 3
InfestedDamaged pod
Un damaged pod
Damaged pod
Un damaged Pod
Damaged pod
Un damaged Pod
PICS Bag 1 16 84 12 88 19 81PICS Bag 2 56 44 62 38 55 45PICS Bag 3 20 80 24 76 22 78
Gunny Bag 1 73 27 72 28 74 26Gunny Bag 2 86 14 92 8 89 11Gunny Bag 3 87 13 83 17 82 18
Uninfested/ControlPICS Bag 4 3 97 5 95 3 97PICS Bag 5 7 93 6 94 4 96PICS Bag 6 4 96 2 98 3 97
Gunny Bag 4 79 21 82 18 72 28Gunny Bag 5 38 62 43 57 48 52Gunny Bag 6 24 76 25 75 33 67
Results-Germination levels
Before starting the experiment
After the experiment
InfestedPICS 1 94% 92 %PICS 2 95% 91%PICS 3 98% 95%Gunny Bag 1 90% 94%Gunny Bag 2 97% 95%Gunny Bag 3 97% 94%Uninfested/ControlPICS 4 94% 93%PICS 5 97% 96%PICS 6 93% 92%Gunny Bag 4 95% 97%Gunny Bag 5 92% 92%Gunny Bag 6 98% 91%
Results-aflatoxin levels
Before the experiment
Aflatoxin content in ppb after the experiment
Sample 1 Sample 2
Sample 1 Sample 2
InfestedPICS 1 1.4
18.11.7 0.0
PICS 2 823.8 1526.4
0.0 4.0
PICS 3 1.7 0.0
0.0 2.5
Gunny Bag 1 33.6 11.8
0.0 1.5
Gunny Bag 2 0.0 0.0
0.0 2.3
Gunny Bag 3 5.6 0.0
0.0 5.3
Uninfested/ControlPICS 4 25.3
46.80.0 1.6
PICS 5 0.0 0.0
0.0 0.0
PICS 6 15.5 23.4
0.0 0.0
Gunny Bag 4 0.0 18.3
0.0 0.0
Gunny Bag 5 80.0 52.9
0.0 0.0
Gunny Bag 6 168.7 78.5
0.0 0.0
Visibility of bruchid damage
Conclusions
Large air spaces in the PICS bags with unshelled pods could affecting the gas composition
Since aflatoxin contamination is also a pre-harvest issue, any toxin produced remains in the produce
Sampling variation is a huge factor in assessing aflatoxin levels
Activity2 – Farmer Trials
As part of an IFAD project a group of groundnut farmers and extension agents visited ICRISAT on April 4th, 2012.
Conducted a demonstration of PICS bag usage.
Activity2 – Farmer Trials
Showed them the trials setup in the laboratory and difference in the control vs PICS stored groundnut.
Convinced, the farmers requested bags for testing. Feedback will be obtained from them after 4 months.
Lessons learned/Way Forward
Micro scale level studies are to be conducted to understand the exact relationship between hermetic storage principle (gas composition) and Aspergillus flavus growth and subsequent aflatoxin contamination
The Groundnut material representing different components of resistance to aflatoxin contamination need to be studied separately (circumstantial evidence for varietal differences)
Thank you