Agriculture Reference
In-Depth Information
Changing Food Systems
A wide variety of fresh fruits and vegetables are grown, transported, and distributed
from numerous farms and orchards in the U.S. and from countries throughout the
world. Although this complex food system provides a greater diversity of produce
items available to large numbers of people, it also potentially increases the exposure
of more consumers to different types of microorganisms on produce. In our complex
food supply chain, with the multiple handling of produce during harvesting, sorting,
washing, transportation, and storage, there is a greater chance of product contamina-
tion and temperature abuse to occur. Fresh fruits and vegetables are often eaten raw,
without cooking, so they are not subject to a lethal heat treatment to kill pathogenic
microorganisms that may be present. When an outbreak occurs, it is often very diffi cult
to trace the source of the problem.
Changing Consumer Preferences
The growing popularity of salad bars and the increase in the number of meals eaten
outside the home can increase the risk of contamination through poor food handling
and preparation practices. Minimally processed produce, such as fresh-cut fruits and
vegetables, although convenient, has not been heat treated to kill pathogens. If this
processing is followed by long storage periods, especially at warm temperatures,
pathogens that may be present can survive and grow, increasing the risk of foodborne
illness (Rangurajan and others 1999). Poor home food preparation practices can also
contribute to an increased risk of produce contamination. When consumers prepare
raw foods of animal origin on a cutting board, and then reuse the cutting board to
prepare fresh produce without having fi rst thoroughly cleaned and sanitized it, there
is an increased risk of foodborne illness in those people who consume the raw produce
item. Following all of the principles of safe home food preparation, including the tips
for the safe handling of fresh produce developed by the FightBac campaign (Partnership
for Food Safety Education 2004) will reduce the risk of foodborne illness. Attention
to detail; proper cleaning and sanitizing of all equipment and utensils used to prepare
foods; and good personal hygiene and frequent hand washing before, during, and after
food preparation are important considerations for all who prepare food for others.
More detailed information about consumer and food-service handling of fresh produce
is provided in chapter 15 .
Changing Microorganisms
Over the last 30-40 years, microbiologists have observed many genetic changes in
microorganisms. These changes include adaptation to stresses in the environment,
allowing microorganisms to survive and grow where they once could not survive.
Bacteria such as
Yersinia enterocolitica
and
Listeria monocytogenes
are capable of
growing slowly at refrigerator temperatures and some bacteria, such as
Salmonella
enteritidis
and
E. coli
O157:H7, can cause serious human illness when only a small
number of cells are ingested. Microbiologists are actively studying these adaptive
stress responses to learn more about how these specialized mechanisms work, so that
better control strategies can be developed. Pathogens that attach to fruits and vegeta-
bles are very diffi cult to remove, so it is important that prevention strategies are
designed to keep these microorganisms from contaminating produce.
