Agriculture Reference
In-Depth Information
should be maintained, in practice, it is often not effectively
managed and temperature fluctuations have been reported.
These interruptions were mostly associated with on- and
off-loading at various points such as at ports (for conven-
tional shipping) or distribution and retail centres
(Keesenberg 2005; Jacobs & Korsten 2004).
FOOD SAFETY
In recent years, food-borne disease outbreaks have been
linked to the global increase in consumption of fresh and
minimal processed produce. Annually, millions of people
are affected by the consumption of contaminated fresh pro-
duce, negatively affecting the economy of the country and
general trust in the supply chain. In the United States alone,
an estimated 76 million cases of food borne illnesses are
reported annually (World Health Organisation 2004).
However, in most countries, a formal link between con-
taminated fresh produce and food borne disease outbreaks
cannot be made due to a general lack of effective monitor-
ing, reporting and regulatory systems. Food borne disease
outbreaks are mainly caused by Salmonella spp.,
Campylobacter spp., Escherichia coli and Jejuni spp.
Several fruit and vegetables (i.e. leaf lettuce, iceberg
lettuce, radish, sprouts, alfalfa sprouts, strawberry and
carrots) have also been associated with disease outbreaks
(De Roever 1998).
Extended global distribution networks and new post-
harvest technologies allow for the marketing of year round
fresh produce (Beuchat 2002). However, some existing
production practices and newly introduced technologies
may allow for product contamination. Any fresh food prod-
uct has the potential to become contaminated with food
borne pathogens during production, handling or distribu-
tion (Brackett 1999). Contamination of fresh produce can
also occur at any point in the fresh produce supply chain
and may represent any of the following improperly man-
aged pre-harvest practices (i.e. the use of untreated manure
or sewage, or contaminated irrigation water and unhy-
gienic human handling) (de Roever 1998; Brackett 1999).
In the post-harvest environment, contamination may occur
due to soiled wash water, human handling, equipment or
unhygienic transportation vehicles, cross-contamination
between fruit and improper storage conditions (De Roever
1998).
Microbial contamination of fresh produce is largely
associated with the contamination of the fructoplane,
while the internal part of the fruit is generally considered
free of human pathogens (Beuchat 1996). The citrus fruit
peel serves as a natural protective barrier which prevents
microbial contamination of the interior flesh. However,
damage to or removal of the fruit rind exposes the edible
portion to potential microbial invasion and spoilage. Cross
contamination can also happen from the peel to the fruit
pulp and this could be of importance in processing. For
instance, an outbreak of salmonellosis was associated
with fresh orange juice in 1995 (Goodrich 1998).
Humidity
The relative humidity (RH) of fruits kept in pallet boxes
should be 90% to 98%, whereas in fibreboard cartons
between 85% and 90% to prevent carton deterioration
(Wardowski & Brown 2001). Fruit stored in wooden or
plastic containers are at near 100% RH (Timmer & Duncan
1999). Water loss from fruit during storage results in
shrinkage and fruit softening. High humidity should be
maintained and free water should not be allowed to accu-
mulate on fruit. This often happens as a result of tempera-
ture fluctuations during storage, and typically, during the
movement of fruit in and out of refrigerated storage during
transport. Moisture on fruit in the post-harvest environ-
ment is conducive to pathogen infection and disease
development.
Controlled atmosphere
Recommended controlled atmosphere (CA) conditions for
maintaining quality in citrus is 0-1% CO 2 and 10-15% O 2
(Ookagaki & Manago 1977). Controlled atmosphere stor-
age conditions effectively reduces rind breakdown.
However, different citrus fruit types respond differently to
CA storage, and therefore factors such as maturity, variety,
humidity and techniques need to be taken into account
(Ladaniya 2008).
Shelf life
Duration of maturity varies with cropping season and can
be 1-2 months for mandarin and tangerines or tangerine
hybrids, 5-6 months for oranges and up to 8 months for
grapefruit (Ladaniya 2008). Extending shelf life is an
important marketing tool for retail and may allow for more
extensive distribution systems.
Phytosanitary challenges
Exportation of fresh citrus often requires a low-temperature
quarantine treatment for control of the Mediterranean fruit
fly ( Ceratitis capitata Wiedemann) for instance (Rodov
et  al . 2000). These quarantine treatments are commonly
applied to fruit before or during transit to ensure that pests
such as fruit flies or scale are not introduced into the
importing country. Fruit may be subjected to either a
standard treatment or a short-term cold treatment.
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