"Where's the Beef?
Investigating Food-Borne Illness". Mr. David A.
Wollert, Northeast State Technical Community College
This exercise deals with E. coli
contamination of food products and the potential costs and
benefits of food irradiation.
Although originally developed
for an introductory microbiology course, it is also suitable for
use in general biology courses, particularly during discussions
of DNA and the causes and effects of mutations.
Materials: Format of
Delivery, Student Learning Objectives, Student Resources.
CNN Video Clips
Topic: Mad Cow
Updates: Biology 5th Ed. CNN Ed 2001 (2:13)
Cattle afflicted with bovine
spongiform encephalopathy (BSE) are shown staggering about.
In Britain, Ireland, and France, about 90 people have died after
exposure to infected beef. Neither BSE nor the human form of
the disease (Creutzfeldt-Jakob disease) is believed to be a
serious threat in the United States. However, the human
disease has an incubation period of ten to fifteen years.
Theoretically, an American could be infected in Europe and bring
the disease into the country, but human-to-human transmission is
extremely difficult. The worksheet includes the URL for the
U.S. Food and Drug Administration, which provides information
about the disease and what is being done to keep it out of the
United States. (Student worksheet provided on CD)
Guinea Worm: Biology 5th Ed. CNN Ed 2001 (2:59)
Citizens of Ghana are shown
suffering from guinea worm infection. They became infected
when they drank water containing the larval form of the
worm. Over the course of a year, the larvae develop into
adults that can reach up to three feet in length. Emergence
of adult worms through the skin causes pain, scarring, and
secondary infections. Ex-President Jimmy Carter is working
to eradicate the Guinea worm by teaching people to treat
potentially infective water with chemicals and filtration and to
monitor and treat known infections. These efforts have
succeeded in decreasing the number of infections in Ghana by
ninety-five percent. (Student worksheet provided on CD)
Cow Disease". Prusiner, Stanley. Current Issues in
Biology Vol. 2. July 2004. pp.2-11.
Mad Cow Disease debuted in
America in December 2003. The bovine spongiform
encephalopathy (BSE) posed a particularly difficult problem for
scientists as prions, which incubate without symptoms for years,
could lead to epidemics. Prions cause multiple diseases in
an array of animals such as deer, elk, and sheep. The prion
is actually a form of protein PrP that can twist into an abnormal,
disease-causing shape. These prions are especially difficult
to kill due to their ability to resist heat, radiation, and
chemicals that can kill other pathogens. Unlike the somewhat
inefficient way the US detects Mad Cow disease now through
immunohistochemistry, antibodies are being developed to detect all
prions, especially the diseased proteins. Prions can arise
spontaneously which is why a feed ban must be implemented to
prevent cows from eating the remains of other slaughtered
cows. Prions are being transferred via feed; prions can also