Agriculture Reference
In-Depth Information
The Origin and Spread of Human
Pathogens in Fruit Production Systems
2
Susan Bach and Pascal Delaquis
Introduction
Botanists defi ne
fruit
as the seed-bearing structures of angiosperms formed from
ovaries after fl owering. In culinary tradition the term refers to fl eshy, succulent plant
parts that are harvested seasonally when the degree of ripeness is conducive to prepa-
ration for immediate consumption or for processing and preservation. Fruit has long
been an integral part of the human diet. There is clear evidence of communal harvest
by ancient hunter gatherers, and recent archeological fi nds suggest that purposeful
cultivation of fi gs was practiced 11,400 years ago in the Near East (Gibbons 2006).
Fruit consumption rates and patterns in premodern times varied widely with geo-
graphic location and cultural practice. At present, many countries in the developed
world are reporting higher intakes, presumably in response to growing awareness of
the benefi ts of fruit for the maintenance of health and the prevention of chronic dis-
eases (Ness and Powles 1997; Takachi and others 2008). Overall production capacity
and international trade are expanding to meet increasing demand, particularly for fresh
whole or minimally processed ( “ fresh - cut ” ) products. Unfortunately, epidemiological
data reveal a corresponding increase in foodborne illnesses caused by consumption of
fresh fruit or fruit products contaminated with infectious microorganisms. Hence there
is an urgent need to recognize potential sources of such hazards, to establish their fate
at all stages along the production-to-consumption continuum, and to develop effective
risk - mitigation strategies.
Role of Fresh Fruit in Foodborne Illness
Consumption of fresh fruit is associated with a range of foodborne illnesses caused
by viruses, bacteria, and single-celled parasites. Table 2.1 was gleaned from several
references provided in this work and is intended to illustrate the diversity of pathogens
linked to known outbreaks together with the range of implicated products.
An exhaustive compilation of U.S. data showed that the number of reported out-
breaks linked to fresh produce including fruit rose between 1973 and 2001
(Sivapalasingam and others 2004). Similar patterns are evident in epidemiological
data from other jurisdictions (De Roever 1999; Sewell and Farber 2001). While the
role of fresh fruit in documented outbreaks is now well established, the relative
contribution to sporadic foodborne illness is unknown.
Analysis of available data hints that
Salmonella
serovars are the single most
common cause of fruit-associated foodborne illness and that infections implicating
verocytotoxigenic
E. coli
(including serovar O157:H7) are occurring with increasing
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