1991) 229

A N EVOLUTIONARY ACCOUNT OF POTATO STORAGE

by Walter Sparks 1

The purpose of storage is to maintain the product in an edible and useable condition over an extended period of time.

In the quarter century 1916 to 1941, potatoes were mostly stored in "clamps" where the tubers were covered with straw, reeds, willows, etc., above ground or in "pits" or "cellars" dug into the ground or hillsides. Usually no method of controlling the temperature was utilized except manual opera- tion of the doors or louvers to allow outside air of acceptable temperature to enter the storage. No humidification system was utilized. Under these conditions, the pulp temperatures of the potatoes varied considerably, and was usually kept below 40~ for sprout control. The tubers were usually not utilized or acceptable for processing.

During the following quarter century (1942-1966) with the advent of frozen potato processing, which has become one of the largest utilization segments of the potato industry today, the necessity for more critical and uniform temperatures was recognized. As a result, sophisticated above ground controlled atmosphere storages were developed utilizing electronic temperature sensing equipment, sprout inhibitors, and air ventilation sys- tems with good air distribution. These systems could maintain tempera- tures within one or two degrees throughout piles of potatoes as large as 500,000 cwt. These employed automatic ventilation systems which mixed warm inside air with outside cool air to provide the desired air tempera- ture and humidity which maintained the quality of the raw product over long periods of time, speeded up the healing of wounds and bruises, and reduced rot and shrinkage. This period has been regarded as the most revolutionary in the development of potato storage and most agree that it was occasioned by the tremendous growth of the potato processing industry.

During the next quarter century period (1967-1991) refinement of chemical sprout inhibitors, humidification systems, computerized venti- lation and air distribution programs, improvement of electronic sensors with digital readouts, storage designs, and employment of many more refrigeration systems, were the main points of progress. Storage has de- veloped to the point that potatoes can now be stored for periods up to 10 or 11 months while maintaining high fresh market and processing quality.

lEO. Box AA, Aberdeen, ID 83210.