but not bruise-free. Sales were 23 percent greater from bruise-free fruits 
even at one-half cent more per pound. The Washington State Apple Commission 
reported that a decrease of 22 percent in the severe bruising of Delicious 
apples on display between 1946 and 1955 had meant a gain of $2 million annually 
to the gorwers of Washington State alone (35). 
Various workers have sought to proportion the responsibility for bruise 
occurrence among the agencies between the grower and the consumer. It appears 
from the surveys available that the orchard handling of apples may be responsi- 
ble for 30 to 72 percent of the total bruising, from 3 to 34 percent may occur 
during grading, packaging, and other handling, and the total from all sources 
may equal 64 to 97 percent by the time the apples reach the consumer (8, 15, 
20, 36, 38, 40, 47, 57, 78, 79, 88, 105, 109, 119). Comin (23)found that 
bruising occurs in every step of apple handling in the following order of im- 
portance: Dumping the apples into field crates, dumping on receiver belts, 
grading, lidding, picking, packing, and orchard handling. Perkins (78) and 
Hauck (47) separately reported that 70 percent of the severe bruising occurs 
after the apples leave the farm. Friedman (33) estimated that transit losses, 
including bruising, approximated $14 per carload for 21,377 cars, and that 
losses during marketing were 21 percent at the wholesale or storage level. It 
is estimated the apples receive an additional 10 to 25 percent bruising by the 
time the customers buy them (104, 120). 
Apples are bruised when cellular structures beneath the skin are broken 
sufficiently to expose the cell contents to intercellular air and oxidation 
(70). Bruises can be divided into three types: (a) those caused by dropping, 
(b) those caused by contact with a rough surface, and (c) those caused by 
pressure (46). Larger apples are more susceptible to mechanical injury than 
smaller ones (44, 78, 119), but all of them bruise and develop skin breaks on 
even short drops of an inch or two (28, 38). Green (43) cautions that to pre- 
vent bruising no free drops, however small, should be permitted. When apples 
are dropped on one another, several bruises usually result (114); the damage is 
greater when apples fall on a flat surface (38). According to Gaston and Levin 
(38), moderately serious bruises occur on Wealthy apples when the pressure on 
them equals about 7 1/2 pounds, on McIntosh at 8 1/2 pounds, on Northern Spy at 
12 pounds, and on Jonathan apples at 18 pounds. 
In 1962, Mohsenin (70) and co-workers (71) reported on equipment they 
used to study precisely the energy required to bruise apples. Their stress 
curves showed that a low force of long duration could produce as much bruise 
as a high force of short duration. This element of time in bruising had not 
previously been recognized. Their data also showed that their test apples were 
most susceptible to bruising about 1 to 2 weeks after harvest. 
Dedolph and Austin (26) determined the severity of bruises did not vary 
with the location of the bruise on Cortland and Northern Spy apples, but there 
was a difference in bruise severity with location on Jonathan and McIntosh 
apples. Other workers found that 99 percent of all bruises and 93 percent of 
all stem punctures occurred on the cheeks of apples (75, 80). These stem 
punctures, often classed as bruises, were found on 5.6 percent of test apples 
shipped in Maine in 1949 (119). Ceponis and co-workers (20) observed stem 
punctures in 6 to 30 percent of the McIntosh apples sampled from retail dis- 
plays in New York City. They found bruises one inch or less in size on 21 to 
100 percent of the same lots. 
Various workers (31, 37, 40, 85, 88, 119) have used diameter of bruised 
areas as the criterion of bruise ~ damage to apples. Burt (14) suggested that 
136 
