A common type of chilling injury seen in supermarkets is pitting on green peppers, but usually the flavor is unaffected unless damage is severe. Additional types of injury due to chilling include skin graying on ripening bananas and failure of peaches to ripen with a juicy texture. The third type of blemish, which is perhaps the least understood in the marketplace, is associated with mixed storage of products that produce ethylene gas with products that are injured by its presence. It is a colorless gas that is thought to coordinate the ripening of these fruits. Ethylene gas is also produced by tractors and other equipment with internal combustion engines and can accelerate ripening of climacteric fruit.
Ethylene can have a number of deleterious effects on other products.
These include faster yellowing and senescence of leafy vegetables, browning reactions such as russet spotting on lettuce leaves, development of bitterness in carrots, and sprouting of potatoes. To avoid blemishes associated with ethylene gas, products that produce it should not be stored with low ethylene producers, which are sensitive to the gas. If this is unavoidable, one method of minimizing damage is to ensure that storage areas are well ventilated. Products such as potassium permanganate that absorb ethylene are available both for use in commercial storage and in home refrigerators. The bottom line is that almost any blemish found on products at harvest is considered to be a grade defect in most markets.