Heat Treatments 
Stoll (123) in Switzerland found that a 5 to 10 minute warm water dip 
(104° F.) before storage gave good scald control. Patterson (75) also reported 
that a hot-water blanching treatment controlled scald. In 1962, Hardenburg 
(unpublished) noted that a 2-minute dip in 120° F. water, or 1 minute in 130° 
water, markedly reduced scald on Stayman apples. However, on several other 
varieties, these heat treatments produced a scald-like injury. 
Storage Temperature 
On many varieties little scald develops if fruit is held continuously at 
low temperatures of 30° to 32° F, The low temperature retards scald, but fruit 
may eventually develop as much scald following low-temperature storage as at 
somewhat higher storage temperatures (27, 33, 90). Martin and Lewis (52) stated 
that symptoms of scald show earlier at 38° F. than at lower temperatures, but 
the severity is worse at lower temperatures. 
Smith (103) reported that warming Bramley's Seedling apples at 2-week 
intervals to 60° F. for 5 days reduced scald, There was a progressive reduction 
in the percentage of apples with scald with warming from the 2d to 12th week in 
storage and a complete absence of scald when apples were warmed in the 16th and 
20th weeks. In the 30th week scald again became very marked. Melville and 
Hardisty (57) and Ginsburg (24) suggested dual-temperature storage for Granny 
Smith apples. Scald was reduced when the storage temperature was 40° F. the 
first month, 36° the second month, and 32° thereafter (57). Padfield (69) work- 
ing with the same variety, found that reducing the temperature from 37°-38° to 
31°-32° after 4 weeks" storage did not assist scald control, Gradual temperature 
reduction and warming at intervals have the disadvantage of increasing the rate 
of fruit ripening. 
Controlled-Atmosphere Storage 
Scald is almost always lower in controlled-atmosphere storage if the 
oxygen is rapidly lowered to 3 to 5 percent (17, 51, 104, 109). It is important 
that the oxygen level be low during the first month or two of storage for good 
scald control (104). If oxygen is reduced to an intermediate level of 10 to 16 
percent, scald is often more severe than in air storage (51, 109). Smock (109) 
has presented much data on McIntosh, showing that when some carbon dioxide was 
present low oxygen levels resulted in less scald than high oxygen. Controlled 
atmospheres reduced scald on all varieties tested except Cortland apples stored 
at 38° F, Martin and Cerny (51) showed that 3 percent oxygen in the absence of 
carbon dioxide was much better than 16 percent oxygen and 5 percent carbon 
dioxide for varieties susceptible to scald and breakdown. Granny Smith apples 
can be kept in good condition for at least 7 months at 32° F. under controlled- 
atmosphere conditions of 5 percent carbon dioxide and 2.5 percent oxygen or 5 
percent carbon dioxide and 16 percent oxygen (96). For best scald control this 
variety should also be wrapped in diphenylamine-treated tissues, Patterson (75) 
reported that scald was reduced by lowering oxygen to 1 percent or by increasing 
carbon dioxide to 12 percent. Carbon dioxide above 12 percent increased scald. 
200 
