Download Safe Food Supply

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8/12/2011
Safe Food Supplies
Name
Sources: FDA, Mayo Foundation, CDC, Univ. of Clemson
Learning Objectives:
1. Demonstrates the effects of UV light on bacteria.
2. Define food borne illness.
3. Name two other methods used to control food borne illness.
Background:
Definition of foodborne illness: Foodborne illnesses are defined as diseases,
usually either infectious or toxic in nature, caused by agents that enter the body
through the ingestion of food. Every person is at risk of foodborne illness.
Food safety is an increasingly important public health issue. Governments all over
the world are intensifying their efforts to improve food safety. These efforts are in
response to an increasing number of food safety problems and rising consumer
concerns.
Infections due to enterohaemorrhagic (causing intestinal bleeding) E. coli, e.g.
E.coli O157, and listeriosis are important foodborne diseases which have
emerged over the last decades. Although their incidence is relatively low, their
severe and sometimes fatal health consequences, particularly among infants,
children and the elderly, make them among the most serious foodborne infections.
In 1999, an estimated 5,000 deaths, 325,000 hospitalizations and 76 million
illnesses were caused by foodborne illnesses within the US.
Bacillus cereus is a spore-forming bacterium that can be frequently isolated from
soil and some food.1 B. cereus spores are more resistant to heat and chemical
treatments than vegetative pathogens such as Salmonella, E. coli, Campylobacter,
and Listeria monocytogenes. If B. cereus grows in food, it can cause two different
types of foodborne illness in humans – vomiting very shortly after eating
contaminated food or diarrhea after a longer incubation.
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Food-borne illnesses cost the United States $152 billion a year, a tab that works
out to an average cost of $1,850 each time someone gets sick from food, a report
by a former Food and Drug Administration economist says.
The three most expensive illnesses for the nation were campylobacter, common in
poultry, at $18.8 billion; salmonella at $14.6 billion; and listeria at $8.8 billion.
Both salmonella and listeria are found in multiple foods.
What is irradiation?
Irradiation is the process of treating food and other consumer products with
gamma rays, x-rays, or high voltage electrons to kill potential harmful bacteria
and parasites, delay sprouting, and increase shelf life. Irradiation is also referred
to ass "ionizing radiation" because it produces energy waves strong enough to
dislodge electrons from atoms and molecules, thereby converting them to
electrically charged particles called ions. Ionizing radiation reduces the number
of disease causing organisms in foods by disrupting their molecular structure and
killing them. Other terms commonly used to identify ionizing irradiation are
"cold pasteurization" and "irradiation pasteurization".
Introduction Questions for Teachers:
How might we protect our food supplies?
How can we keep our hands clean?
How might heat or cooking help?
Could radiation help us and what forms might work?
SUPPLIES
1. 1 LB plate
2. 1 LB plate with bacteria growing
3. Cotton swab
4. 370C incubator
5. UV light box
6. piece of paper
PROCEDURE (Make sure to initial your plate)
1.
2.
3.
4.
Take and draw 3 equal distant lines across your LB plate.
Label one area 0 for 0 seconds write small
Label one area 30 seconds (0.5 min.)
Label one area 60 seconds (1 min.)
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5. Label one area 120 seconds (2 min.)
6. Take your LB plate with bacteria and scrape some cells up
with your cotton swab.
7. Drag the cotton swab across the 0 second area of your LB
plate
8. Repeat for 30, 60 and 120 areas.
9. Expose each area of the plate to the UV light for the required
amount of time. Use your piece of paper to protect the other
areas.
10.Incubate for 20-24 hours at 37 degrees.
RESULTS:
Reading:
http://www.clemson.edu/extension/hgic/food/food_safety/illnesses/hgi
c3620.html
http://www.foodhaccp.com/1news/020909f.html
http://www.mcvitamins.com/irradiated_foods.htm