Fresh-cut produce tend to be highly perishable,
value added products that have been prepared for immediate and convenient
consumption by removal of inedible components such as stems, skin,
pits and / or cores. Fresh-cut produce is often offered for sales
in packaging that is specially designed to protect delicate products
from physical injury and sometimes to extend shelf life. Fresh-cut
produce continues to increase in demand with cantaloupe among the
most important in terms of volume produced and value.
Fresh cut products must not only be aesthetically pleasing, but also
comply with food safety requirements. Plant cell injury, senescence,
and stress facilitate growth of microorganisms. Potential for survival
and growth of microorganisms on fresh-cut products vary in proportion
with the amount of injury occurring during the cutting process. Microbial
proliferation on fresh-cut cantaloupe is problematic. Human pathogens
found on produce include bacteria, viruses, and parasites. Several
outbreaks of food poisoning caused by Salmonella species in recent
years have been traced to cantaloupes. Irradiation has the potential
to eliminate vegetative forms of bacterial pathogens such as Salmonella,
as well as parasites, and also to extend fresh-cut product shelf life.
Low-dose electron beam irradiation of fresh-cut cantaloupe offers
promise as a method of increasing product shelf life. Based on respiration
rates, microbiological bloom, and informal sensory evaluations, irradiated
samples appeared to maintain preferred quality for 3-5 days longer
than non-irradiated controls. Respiration rates of the controls increased
after day 8 whereas irradiated samples showed a similar trend only
after day 13. Knowledge of effects of irradiation on product respiration
rates, as summarized in Eq. [2], should provide a means to develop
modified atmosphere packaging that could further enhance the ability
of irradiation to extend fresh-cut cantaloupe shelf life.
Cantaloupes (Cucumis melo) in three separate trials were cut into
1-inch cubes and irradiated at 0, 0.25, 0.5, 1.0, 1.25, or 1.5kGy;
0, 0.1, 0.2, 0.3, 0.4, 0.5, or 0.7kGy; and 0, 0.3, 0.6, or 0.9kGy,
respectively. They were then stored in air at 3°C for up to 20
days, and respiration rate, measured as carbon dioxide (CO2) production,
microbiological counts [Total Plate Count (TPC) and yeast and molds],
texture, and color were measured during storage. Respiration rates
were initially higher in irradiated cantaloupe. After 8 days respiration
was similar between irradiated and control fruit. Irradiation moderated
increases in respiration in a dose-dependant manner. Highest irradiation
doses resulted in initial TPC reductions of 1.5 log compared to the
non-irradiated controls, and also prevented the 2.5 to 3 log TPC increases
seen in controls after day 10 to 11 days of storage. Texture differed
on day 1, when controls were most firm, but irradiation maintained
greater firmness than controls after day 7. Irradiation of fresh-cut
cantaloupe has potential for shelf life extension and for integration
with modified atmosphere packaging systems.
