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Coffee bag project from Nicaragua


Coffee is the second largest commodity in the world. Coffee harvesting is labor intensive and tends to cause physiological problems to many coffee plant workers. The IEA has promoted the development of a simple, cheap yet highly effective harvesting bag that significantly alleviates physiological problems associated with the “picking by hand” harvesting.

About Project

Hosting Federated Society



The IEA Lighthouse Project


Barbra Silverstein   Kate Stewart   Stephan Bao   Steve Russell (USA)   Rogelio Jose Caballero Martinez   Cipriano Mercedes Sandoval Sanchez   Marcos Aurelio Vanegas Pena (Nicaragua)  


IDCChair@iea.cc (Barbara Silverstein)


Coffee is the second largest commodity next to crude oil. It is grown in twenty-eight countries ( http://www.rombouts.com/uk/universe/coffee-producing-countries ). At least half a million workers are involved in coffee growing and harvesting.
There are several methods for harvesting coffee cherries. Stripping by hand is a typical method. Cherries are stripped off onto a sheet laid on the ground, when 75% of them are judged to be perfectly ripe. This method is more cost effective than harvesting the same trees many times. Combing cherries with flexible teeth is another typical method, which is more precise in collecting ripe cherries. But, it can be less cost effective. Use of machines (e.g. tractors) is available, but not complete. Picking by hand is precise in choosing ripe cherries and inexpensive for certain regions, therefore still widely adopted. But, this is labor intensive and tends to cause physiological problems.

Photo 1: A worker is holding cherries in a straw basket.
Photo 1 shows a typical scene found in many coffee plants. A worker binds a traditional straw basket on his waist and holds cherries in it.

Photo 2: A worker is filling a plastic bag with cherries from a straw basket.
Photo 2 shows a worker trying to fill a plastic shipping bag with cherries held in a waist basket. This method forces workers to take unfavorable postures that eventually cause physiological problems.

A simple plastic bag was designed to alleviate the problem. The bag is cylindrical and can be held firmly in front the body (Photo 3). Both ends are open (the left of Photo 3), but the bottom end can be closed by folding and tying with stings (the right of Photo 3).

Photo 3: A worker is showing the improved coffee harvesting bag.

Photo 4: Cherries simply fall into a shipping bag when the bottom of the harvesting bag is released.
Workers can collect and hold cherries without holding their bodies in excessively twisted postures repeatedly. Workers can fill the plastic shipping bag, just by releasing the bottom of the bag (Photo 4).

Validation study

A research group consisting of two researchers representing the IEA and local (Nicaragua) researchers examined the benefit of the improved bag. The followings summarize the outline of the validation study:
  • Informed consent described to subject workers, first in group and then individually;
  • Electromyography (EMG) was calibrated at the beginning, the middle and the end of workday (Photo 5);
  • Randomly assign an improved bag or a traditional basket on day and other next day; and
  • Questionnaires about aches and pains were given at the beginning and the end of the shift, and responses analyzed in terms of age, gender, and years of working in coffee harvesting.
The results of the data analysis evidenced that the improved harvesting bag was well received by the subject workers and their physiological strain was shown to be alleviated significantly both subjectively and objectively (EMG).

Refer to the following for more details.

Silverstein, B., Stewart, K. and others, “xxx,” The Journal of Human Factors and Ergonomics Society, in press (2012).

Photo 5: EMG measurement

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