Soggy breakdown is a physiological disease of apples occurring most frequently on Jonathan, Northwest Greening, Grimes Golden, Wealthy, and Golden Delicious stored at 32 °F, or slightly lower. Soggy breakdown first appears as a light-brown discoloration in the cortex. Continued development of the disease may involve a large part of the cortex, sometimes producing a band of brown tissues in the central cortex between the healthy tissues just under the skin and those around the core (see photo). Affected tissues are sharply delimited from healthy ones, are generally moist, soggy, and have a fermented taste. The soggy tissues may become mealy in advanced stages of the disease. The skin of the apple may appear normal, except in the late stages of the disease. Seriously affected fruits, however, have a characteristic sponginess that can be detected by squeezing the fruits.
Soggy breakdown is akin to soft scald in the conditions responsible for its occurrence. It is more prevalent on apples stored at 30 °F than on apples stored at 32° and is usually prevented entirely by storage at 36° to 40 °F. It is usually greatly increased by delayed storage.
Holding apples in an atmosphere containing 20 to 30 percent carbon dioxide for 2 days during the cooling period has largely or entirely prevented the later development of soggy breakdown.