Mechanical and Temperature Effects on Shelf Life Stability of Fruits and Vegetables - Food Shelf Life Stability: Chemical, Biochemical, and Microbiological Changes - page 49

TABLE 2.3
Bruising of Potato Tubers (cv Bintje) at Different Heights,
with or without Air Humidification at a Storage Temperature
of 3 to 5°C

Bruising, a % of tubers
With Air Humidification

Height above
the Ground, m Without Air Humidification

0.25 24 64

0.50 23 51

1.00 19 39

1.50 12 32

2.00 7 11

2.50 2 10

3.00 0 1

Average 12 30

a Percentage of tubers with moderate and severe bruises.

From Meijers, C.P., Post-Harvest Behaviour, Store Design, Storage Practice, Han-
dling , Rastovski, A. and van Es, A., Eds., Centre for Agricultural Publishing and
Documentation, Wageningen, the Netherlands, 162-168, 1987. With Permission.

susceptible to bruising when sorted immediately after harvest. Sorting is best done
after the curing period. Excessive compression pressure on onions is manifested not
only as bruises but crushing of the bulbs when they are packed and stacked in flexible
packages like gunny bags. Maini and co-workers 44 reported that 7% of the bulbs
were crushed when bags were stacked 5 layers high, and 28% were crushed when
bags were stacked 7 layers high.
Strawberries are also sensitive to handling operations during and after harvest
because of their very tender skin. Picking operations have been known to inflect the
major portion of physical damage. They have a short shelf life because of their
susceptibility to attack by pathogens and high rates of respiration (20 to 40 mg
CO 2 /kg h at 20°C). 45 It was reported that between 66 and 99% of the semi-colored
to ripe strawberry fruits were bruised after a journey of 1600 km and six handling
operations in Australia. 46 In Denmark, more than 20% of the strawberries were found
to be bruised upon reaching the retail outlets. 32 In the U.S., 70 and 48% of the
strawberry shipments in the New York market monitored between 1972 and 1984
incurred bruise damage and “soft leaky fruit” disorder, respectively. 47 “Soft leaky
fruit” disorder is the result of over-maturity, high temperature, rots, freezing, or
mechanical injury. Bruising in strawberries appears as discoloration similar to apples.
When a strawberry fruit is bruised, cells burst and the sap is released into the air-
filled interstitial spaces. 46
A study on transporting ripe tomatoes was conducted by Itokawa and co-
workers 48 in Japan. During conventional transport using a small size truck, the
vertical vibration acceleration level was reportedly less than 15 m/s 2 and the fre-
quency range was less than 30 Hz exerted on the corrugated cardboard boxes.