Biomedical Engineering Reference
In-Depth Information
2.3.1
Transportation
Since most consumers do not shop directly from the local farmer, the global nature
of the food supply can result in food traveling hundreds, if not thousands of
kilometers before reaching the local retail store. Over 200 billion metric tons of
foods are transported every year globally, by land, sea and air (Bendickson
2007
).
Most of the food transported has unique container storage, temperature and han-
dling requirements. Food is very vulnerable to contamination during transportation.
Some of the risk factors that can be associated with transportation are temperature
abuse, unsanitary cargo areas, improper loading/unloading practices, damaged
packaging, poor road conditions and human error (Ackerley et al.
2010
). When it
comes to retail, trucks are the preferred mode of transportation to the store. In the
USA, over 80 % of all food shipments and 91 % of temperature controlled freight
shipments are transported by truck (Ackerley et al.
2010
).
A recent study identifi ed the top fi ve food safety hazards across all modes
of transportation; (1) lack of security for transportation units or storage facilities;
(2) improper handling practices of food products awaiting shipment or inspection;
(3) improper refrigeration or temperature control of food products; improper
management of transportation units and storage facilities; (4) improper loading
practices and (5) conditions of equipment (Ackerley et al.
2010
). The foods most at
risk were identifi ed as fresh produce, raw and refrigerated ready-to-eat (RTE) foods,
raw meat and raw poultry, eggs and egg products and raw seafood (Ackerley et al.
2010
). The global nature of the food supply results in many of the food products
spending a large amount of time in the process of transportation. Estrada-Flores
et al. (
2006
) tracked the temperature of frozen fi sh over 20 days of transport and
showed that the temperature of the fi sh continued to rise to the point that it could
support the growth of
Yersinia enterocolitica
and
Listeria monocytogenes
.
There is a strong possibility of cross-contamination when multiple food com-
modities are shipped together. This can sometimes happen with half-full loads,
where companies may ship several food items together (Keener
2003
).
2.3.2
Storage
2.3.2.1
Time and Temperature
Microorganisms thrive in warm temperatures. Temperatures between 4 and 60 °C
are referred to as the Danger Zone, as these are the temperatures in which microor-
ganisms grow and thrive. Many microorganisms are killed when exposed to tem-
peratures of 60 °C for several minutes. However, temperatures below freezing do
not kill most microorganisms, but invoke dormancy, a time during which the micro-
organisms cannot grow and multiply. It is also important to know that some bacteria
such as
L. monocytogenes
, actually grow well at refrigeration temperatures.
