Food safety WORLD OF MICROBIOLOGY AND IMMUNOLOGY226•
The Centers for Disease Controldata has demonstrated
that Campylobacter jejuniis the leading cause of foodborne
illness in the United States. Another bacteria, Salmonellais
the next leading cause. The third cause of foodborne illness is
the bacterium Escherichia coliO157:H7. Poultry and ground
meat are prime targets for bacterial contamination. Indeed,
monitoring studies have demonstrated that some 70–90% of
poultry carry Campylobacter jejuni.
Food safety needs to consider the influences of the
microbial pathogen, the human host and the exposure of the
food to the environment that promotes contamination. The
environment can include the physical parameters such as the
temperature, moisture, or other such factors. As well the envi-
ronment can be the site of the foodstuff, such as the farmyard
or the processing plant. Ensuring safety of food from micro-
bial threat must consider all three of the influences. For exam-
ple, reducing the length of time that a food is exposed to a
questionable environment, but doing nothing to remove
microbes from the environment only slightly reduces the risk
of food contamination. Significant protection of foods
depends on reducing the risk from the environment, microor-
ganism of interest and of the human host.The treatment of foods prior to consumption is a vital
factor in ensuring food safety. Some of these treatments have
been known for a long time. Salting of meats and drying of
foods on long sea voyages was practiced several centuries
ago, for example. The canning of foods began in the eigh-
teenth century. Within the last 150 years, the link between
hygienic conditions and the quality and safety of foods was
recognized. Some of the advances in food safety arose from
the need for foods on long military campaigns, such as those
undertaken by Napoleon in the nineteenth century. Also,
advances were spurred by the demands of the nascent food
industry. As the distance between the farm and the market
began to grow larger, and the shipping of food became more
commonplace, the problems of food contamination became
evident. Practices to render food safe for shipping, storage
and subsequent consumption were necessary if the food
industry was to grow and flourish.
The heat treatment of milk known as pasteurization
began in the 1890s. Pasteurization is the transient exposure of
milk to temperatures high enough to kill microbes, while pre-
serving the taste and visual quality of the milk. Milk is now
routinely pasteurized before sale to kill any bacteria that
would otherwise growth in the wonderful growth medium that
the liquid provides. Within the past thirty years the use of radi-
ation to kill microbes in food has been utilized. While a very
effective method to ensure food safety, irradiation is still sub-
ject to consumer uncertainty, which has to date limited its use-
fulness. As a final example, within the past two decades, the
danger posed by intestinal bacterial pathogens, particularly
Escherichia coliO157:H7 has resulted in the heightened
recognition of the need for proper food preparation and per-
sonal hygiene.
Food safety is also dependent on the development and
enforcement of standards of food preparation, handling and
inspection. Often the mandated inspection of foods requires
the food to be examined in certain ways and to achieve set
benchmarks of quality (such as the total absence of fecal col-
iform bacteria). Violation of the quality standards can result in
the immediate shut down of the food processing operation
until the problem is located and rectified.
Most of the food safety legislation and inspection
efforts are aimed at the processing of food. It is difficult to
monitor the home environment and to enforce codes of
hygiene there. Yet, food safety in the home is of paramount
importance. The improper storage of foods prepared with raw
or undercooked eggs, for example, can lead to the growth of
microorganisms in the food. Depending on the microbe and
whether toxins are produced, food poisoning or food intoxica-
tion can result from eating the food dish. Additionally,
improper cleaning of cutting and other preparation surfaces
can lead to the cross-contamination of one food by another.
Good hygienic practices are as important in the home as on the
farm, in the feedlot, and in the processing plant.See also BSE and CJD disease; BSE and CJD disease,
advances in research; BSE and CJD disease, ethical issues and
socio-economic impact; Enterotoxin and exotoxin; Food
preservation; Transmission of pathogensRaw oysters can harbor microbial toxins.womi_F 5/6/03 2:15 PM Page 226