Updated on January 5, 2024


Created on August 27, 2015

Purdue Improved Cowpea Storage (PICS) Bags

Upcoming Update

The PICS bag is a cost-effective, triple-layer hermetic storage bag which permits farmers to store their grains without the use of insecticide thus providing them healthy, clean food that can be stored for longer.

Developed By
  1. Purdue University
Tested By
  • Department of Entomology in the College of Agriculture at Purdue University
Content Partners


Product Description

The Purdue Improved Cowpea Storage (PICS) bags are high density, hermetic polyethylene bags, with ultra-thick walls of 80 microns, intended to maintain the viability of cowpeas for planting, minimize mold growth and accumulation of mycotoxins and control storage insect pests, thereby enabling farmers to store their grains without the use of insecticides.

The PICS projects (PICS2 and PICS3) carried out research to explore the usefulness and value of PICS bags of crops including maize, sorghum, wheat, rice, peanut, common bean, hibiscus seed, mung bean, pigeon pea and bambara groundnut.

Target SDGs

SDG 2: Zero Hunger

SDG 1: No Poverty

Market Suggested Retail Price


Target Users (Target Impact Group)

Household, Community, Small and Medium-sized Enterprises

Distributors / Implementing Organizations

Purdue University in partnership with manufacturers private entrepreneurs and vendors.

Competitive Landscape

Direct competitors include ZeroFly Storage Bag.

Manufacturing/Building Method

Mass produced. PICS project staff members currently work with several African-based plastic manufacturers to produce PICS triple-layer bags. Interview with representative.

Intellectural Property Type


User Provision Model

African entrepreneurs and rural communities are starting new businesses focused on purchasing the PICS bags from manufacturers and selling them to farmers through their retail networks. Farmers can buy it from manufacturers and local businesses, approved vendors in 50kg and 100kg capacity sizes at a cost between $2 and $4 USD. Available at market price, depending on the region.

Distributions to Date Status

In 5 years, more than 2.4 million PICS bags were sold in West and Central Africa.

Materials of construction

High density polyethylene PICS bags, with ultra-thick walls of 80 micron

Grain storage duration

~3 months

Holding Temperature (°C)


Protection from insect entry


Storage capacity (kg)


Temperature control


Design Specifications

  • Triple layered storage bags made of high density polyethylene, with ultra-thick 80 micron walls.
  • PICS were originally designed for storage of cowpeas, an African staple, specifically.

Product Schematics

Technical Support

Available in the form of an instruction manual

Replacement Components



PICS bags are used and reused to store cowpeas up to 4 consecutive years. Interview with representative

Manufacturer Specified Performance Parameters

Performance targets: Interview with representative

  • PICS bags can be used and reused to store cowpeas for up to 4 consecutive years and reduce loss of cowpeas grain to insect infestation.
  • Once PICS bags are no longer fit to store cowpeas, they are used for other purposes.
  • Reused PICS bags reduce the cost of storage for small-scale.
  • Using damaged PICS bags for other purposes reduces the environmental impact.

Vetted Performance Status

Physical activity and reproduction of bruchids in PICS bags ceases due to hypoxia.

  • Hypoxia is due to insect metabolism and oxygen barriers presented by the bag walls. Oxygen deprivation deprives the bruchids of their most important source of water. PICS bags are used and reused to store cowpea up to four consecutive years. Once PICS bags are no longer fit to store cowpea, they are used for other purposes.
  • Storage of conventional farmer cassava chips in PICS Bags was only successful till 4 months not beyond. Losses in PICS bags exceeded 8% after 6 months of storage. PICS bags prolong only the storage of chips by approximately 1 month. Chips size did not allowed oxygen reduction in PICS bags leading to hermetic conditions
Research findings on economic viability and effectiveness of PICS bags with respect to crops beyond cowpea.


Hermetic sealing is compromised by bag wall ruptures. Once PICS bags are no longer fit to store cowpea, they can be used for other purposes.

Complementary Technical Systems


Academic Research and References

Available [online] at: http://www.entm.purdue.edu/PICS3/journal_articles.php

  1. Vales, M.I., Ranga Rao, G.V., Sudini, H., Patil, S.B., & Murdock, L.L. (2014) Effective and economic storage of pigeonpea seed in triple layer plastic bags. Journal of Stored Products Research, 58, 29-38
  2. Murdock, L.L., & Baoua, I.B. (2014) On Purdue Improved Cowpea Storage (PICS) Technology: Background, Mode of Action, Future Prospects. Journal of Stored Products Research, 58, 3-11
  3. Baoua, I., Amadou, L., Ousmane, B., Baributsa, D., & Murdock, L.L. (2014) PICS bags for postharvest storage of maize in West Africa. Journal of Stored Products Research, 58, 20-28
  4. Baoua, I., Amadou, L., Baributsa, D., & Murdock, L.L. (2014) Triple bag hermetic technology for post-harvest preservation of Bambara groundnut (Vigna subterranea (L.) Verdc.) Journal of Stored Products Research, 58, 48-52
  5. Affognon, H., Njoroge, A.W., Mutungi, C.M., Manono, J., Lamuka, P.O. & Murdock, L.L. (2014). Storage of mung bean (Vigna radiata [L.] Wilczek) and pigeonpea grains (Cajanus cajan [L.] Millsp) in hermetic triple-layer bags stops losses caused by Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). Journal of Stored Products Research, 58, 39-47
  6. Baoua, I. B., Amadou, L., Lowenberg-DeBoer, J. D., & Murdock, L. L. (2013) Side by side comparison of GrainPro and PICS bags for postharvest preservation of cowpea grain in Niger. Journal of Stored Products Research 54, 13-16
  7. Baoua, I. B., Amadou, L., & Murdock, L.L. (2013) Triple bagging for cowpea storage in rural Niger: Questions farmers ask. Journal of Stored Products Research 52, 86-92
  8. Murdock, L.L., Sithole-Niang, I., and Higgins, T.J.V. (2013) Transforming the cowpea, an African orphan staple crop grown predominantly by women, pp. 221-232 In Successful Agricultural Innovation in Emerging Economies: New Genetic Technologies for Global Food Production (edited by D.J. Bennett and R.C. Jennings), Cambridge University Press
  9. Baoua, I. B., Amadou, L., Margam, V., & Murdock, L.L. (2012) Comparative evaluation of six storage methods for postharvest preservation of cowpea grain. Journal of Stored Products Research 49, 171-175
  10. Baoua, I. B., Margam, V., Amadou, L., & Murdock, L.L. (2012) Performance of triple bagging hermetic technology for postharvest storage of cowpea grain in Niger. Journal of Stored Products Research 51, 81-85
  11. Murdock, L.L., Margam, V., Baoua, I., Balfe, S., & Shade, R.E. (2012) Death by desiccation: effects of hermetic storage on cowpea bruchids. Journal of Stored Products Research 49, 166-170
  12. Hell, K., Edoh Ognakossan, K., Lamboni, Y., (2014) PICS hermetic storage bags ineffective in controlling infestations of Prostephanus truncates and Dinoderus spp. In traditional cassava chips. Journal of Stored Products Research, 58, 53-58
  13. Williams, S. B., Baributsa, D., Woloshuk, C. (2014). Assessing Purdue Improved Crop Storage (PICS) bags to mitigate fungal growth and aflatoxin contamination. Journal of Stored Products Research.
  14. Jones, M., Alexander, C., Lowenberg-DeBoer, J., (2014) A simple methodology for measuring profitability of on-farm storage pest management in developing countries. Journal of Stored Products Research, 58, 67-76
  15. Jones, M., Alexander, C., Ricker-Gilbert, J., Olynk Widmar, N.J. and Lowenberg-DeBoer, J., 2012, “Do Insect and Mold Damage Affect Maize Prices in Africa? Experimental Evidence from Malawi“, revision submitted to American journal of Agricultural Economics.
  16. Ricker-Gilbert, Jacob & Jones, Michael, 2012. “Does Access to Storage Protectant Increase Smallholder Adoption of Improved Maize Seed? Insights from Malawi,” 2012 Annual Meeting, August 12-14, 2012, Seattle, Washington 124658, Agricultural and Applied Economics Association.

Comments from the Community

1 Comment

  1. destochild says:

    where can we buy this bag

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