Roots and tubers are a major part of the diet, food energy and nutrient source for more than 1 billion people in the developing world. Root crops are used to produce food products including composite flours, noodles, chips and dehydrated products. They provide about 40% of the diet for half of the sub-Saharan African population. Cassava has become one of the developing world’s most important staples, providing a basic diet to about 500 million people. Cassava has also become an important export crop for animal feed in Europe.
Roots and tubers—potatoes, sweet potatoes, cassava, yams and taro—are known as the starchy foods. They are high in carbohydrates, calcium and vitamin C, but low in protein. These foods are the subsistence crops in some of the poorest countries. Several root food crops are staples in major world regions. These include the yam in Indochina, Indonesia and Africa; the potato in South America, Central America, Mexico and Europe; and the cassava and sweet potato in South America (Alexandratos 1995).
The potato was introduced into Ireland in the 1580s, and a small plot could feed a six-child family, a cow and a pig. Moreover, the crop could remain in the soil protected from the winter freezes and fires. The potato became the food of the poor in Ireland, England, France, Germany, Poland and Russia. In 1845, a blight struck the potato across Europe, which resulted in the great, fatal potato famine in Ireland, where substitute crops were unavailable (Tannahill 1973).
The potato is still a principal crop in the developed world. Its production continues to increase in the United States, and much of this increase is attributed to processed potatoes. Growth in processed potatoes is occurring in chips and shoestrings, frozen French fries, other frozen products and canned potatoes. The principal occupational hazards are related to injury and are experienced during the mechanical harvesting operation. In a Canadian study, potato farmers were found to be at elevated risk of pancreatic cancer, but no association was made with an exposure.
Each moving part of the potato harvester carries the potential for injury. The tractor’s PTO shaft, which connects the tractor and the harvester by universal joints or yokes, is the source of kinetic energy and of injuries. The PTO shaft should be shielded. The most common injury on a PTO shaft occurs when the yoke catches a loose piece of clothing, entangling the wearer.
All hydraulic systems operate under pressure, even as much as 2,000 pounds per square inch (14,000 Kpa), which is three times the pressure needed to penetrate skin. Thus a worker should never cover a leaking hydraulic hose with a finger since the fluid could be injected through the skin. If any fluid is injected into the skin, it must be surgically removed within a few hours or gangrene may develop. If any point in the hydraulic system fails, a serious injury can occur. A ruptured hydraulic hose can spray fluid a great distance. Hydraulic systems store energy. Careless servicing or adjusting can lead to injury.
A pinch-type injury can occur where two machinery parts move together and at least one of them moves in a circle. Gear and belt drives are examples of pinch points. Clothing or body parts can catch and become drawn into the gears. Proper guarding of potato harvester parts reduces the chance of a pinch-type injury.
A wrap-type injury can occur when an exposed, unshielded rotating component, such as a PTO shaft, entangles a loose piece of clothing: a sleeve, a shirt-tail, a frayed piece of clothing or even long hair. Smooth PTO shafts with rust or nicks can be rough enough to catch clothing; a slowly rotating PTO shaft must still be regarded with caution. However, the rounder, smoother shafts are less likely to catch clothing than square shafts. The universals at the end of the PTO shafts are the most likely to catch loose clothing and cause a wrap-type injury. These bulky parts extend beyond the PTO shaft and can cause a wrap-type injury even if one is clear of the PTO shaft. PTO shafts from the tractor to the potato harvester must be guarded. No one should work amid unsafe conditions such as unshielded PTO shafts.
Shear points are areas where two pieces move in a cutting motion. A finger placed in a boom joint or between a fan belt and the pulley would be quickly severed. The belt, turned by the engine that drives the fan, is a site for amputation as well as other bodily injuries. Again, proper shielding of potato harvester parts reduces the chance of a shear injury.
Crush points are found where two objects move towards each other, or an object moves toward a stationary object. Big trucks are involved in a potato harvest. Movement in the field and especially in a closed facility such as a potato storage building can lead to runovers and crushed feet or legs.
A pull-in injury occurs when a worker is pulled into machinery. Pull-in injuries can occur any time there is an attempt to remove something from a potato harvester while it is operating, even if it is not moving forward.
Thrown-object injuries occur when projectiles are hurled. Air-assisted potato harvesters routinely throw soil and small rocks in the process of separating potato tubers from rocks. The soil and debris are thrown with enough force to cause eye injuries.
Fortunately, there is a great deal that can be done to avoid injuries. Clothing can make the difference between being caught in a pinch or wrap point and being safe. Loose, long hair can catch in wrap and pinch points and drag the worker’s head into a dangerous spot. Long hair should be securely tied. Skid-resistant shoes help keep the worker from slipping while standing on the sorting platform, which may be treacherous with mud and vines. Gloves, if worn while working on the sorting table, should be tight fitting and not have frayed edges or floppy cuffs.
Attitude, alertness and avoiding dangerous situations complement safe attire. No one should ever mount or dismount a potato harvester while it is in motion. The rider must wait until the harvester stops. Many of the serious and debilitating injuries occur from falling and being crushed while attempting to mount or dismount a moving harvester. One should try to be in a stable position before the tractor starts to pull the potato harvester. This will reduce the possibility of falling down as the tractor jerks forward. No one should ever be between the tractor and the harvester while they are in motion or when they are started. The tractor operator or the workers riding the potato harvester should never be close enough to touch the PTO shaft while it is running or when it is started. Harvesters should not be lubricated, adjusted or repaired while running. No attempt to dislodge anything from the belts should be made while they are in motion.