1. How are they classified?
Objective 8.L.1 – Summerize the basic characteristics of viruses, bacteria, fungi, and parasites relating to the spread, treatment, and prevention of disease.
KEY QUESTIONS
What are Pathogens?
How are they classified?
Are they good or bad?

2. What are Pathogens?
A pathogen or infectious agent is a biological agent that causes disease or illness to its host.

3. What is a pathogen?
A biological organism such as Bacteria, Viruses, Fungi, and Protozoa that make you sick.
Why do they make you sick?
To get the energy they need to survive and reproduce
How do they make you sick?
They produce poisons (toxins) that result in fever, headache, vomiting, and diarrhea and destruction of body tissue.
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

4. Where do you get a pathogen?
Indirect contact
Contact with people who are sick
Direct or indirect
Food, Water, or other Surfaces that are contaminated
Foods that could be contaminated
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006
Direct contact

5. What are some common pathogens?
E. coli O157:H7
Pathogenic E. coli
(like O157:H7)
Found in ground beef, contaminated fruits and vegetables
Salmonella
Found in raw meats, poultry, eggs, sprouts, fruit and vegetables
Listeria
Found in deli foods, lunch meats, smoked fish and vegetables
Salmonella
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006
Listeria

6. A Closer Look – Where do you get a pathogen
Direct Contact
Indirect Contact
Foods and water may be contaminated
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

7. What are the 6 Kingdoms? Archaebacteria Eubacteria Monera Protists
Fungi
Plants
Animals
Monera

8. Kingdom Monera Most numerous organism on Earth Most Ancient
Microscopic Prokaryotes
Evolution has yielded many species adapted
to survive where no other organisms can.
Grouped based on:
Structure, physiology, molecular Composition,
reaction to specific types of stain.
Eubacteria= Germs/bacteria
Archaebacteria

9. Archaebacteria Live in extreme locations: Oxygen-free environments
Concentrated salt-water
Hot, acidic water
Methanogens
Methanogens
make methane
(natural gas
Thermophiles can grow
In hot springs and boiling
water
Halophiles can turn extremely salty
environments pink

10. Eubacteria
Heterotrophs –found everywhere and lives off living/dead organisms
Photosynthetic autotrophs – makes their own food
Chemosynthetic autotrophs
The first organisms on Earth to do modern photosynthesis

11. What are bacteria? Single celled organisms Very small
Need a microscope to see
Can be found on most materials and surfaces
Billions on and in your
body right now
This is a pore in human skin and the yellow spheres are bacteria
E. Coli O157:H7 can make you very sick.
Streptococcus can cause strep throat.
This E. coli helps you digest food.

12. Bacteria compared to a white blood cell that is going to eat it

13. Clean skin has about 20 million bacteria per square inch

14. What do they look like? Three basic shapes
Rod shaped called bacilli (buh-sill-eye)
Round shaped called cocci (cox-eye)
Spiral shaped
Some exist as single cells, others
cluster together
Bacilli
Cocci
Spiral
Cluster of cocci
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

15. Bacteria are ALIVE! What does it mean to be alive?
They reproduce (make more of themselves)
They need to eat
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

16. How do bacteria reproduce?
Grow in number not in size
Humans grow in size from child to adult
Make copies of themselves by dividing in half
Human parents create a child
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

17. How do bacteria reproduce?
Binary Fission- the process of one organism dividing into two organisms
Fission is a type of asexual reproduction
Asexual reproduction- reproduction of a living thing
from only one parent
How?...
The one main (circular) chromosome makes a copy of itself
Then it divides into two

18. A closer look at how Bacteria reproduce
Binary Fission – reproduction in which a bacteria cell divides into two cells that are the same as the original. They can reproduce in 15 minutes if resources are available.

19. How do bacteria eat?
Photosynthetic bacteria
Some make their own food from sunlight—like plants
Some are scavengers
Share the environment around them
Example: The bacteria in your stomach are now eating what you ate for breakfast
Some are warriors (pathogens)
They attack other living things
Example: The bacteria on your face can attack skin causing infection and acne
Harmless bacteria on the stomach lining
E. Coli O157:H7
is a pathogen
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

20. Bacteria are of immense importance because of their rapid growth, reproduction, and mutation rates, as well as, their ability to exist under adverse conditions.
The oldest fossils known, nearly 3.5 billion years old, are fossils of bacteria-like organisms.

21. Are all bacteria pathogens?
No, most are harmless
Some are even helpful
Examples of helpful bacteria:
Lactobacillus: makes cheese, yogurt, & buttermilk and produces vitamins in your intestine
Leuconostoc: makes pickles & sauerkraut
Pediococcus: makes pepperoni, salami, & summer sausage
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

22. A Closer Look – Helpful Bacteria
Pediococcus - used in production of fermented meats
Lactobacillus casei – found in human intestines and mouth to improve digestion
Leuconostoc cremoris – used in the production of buttermilk and sour cream
Lactobacillus bulgaricus – used in the production of yogurt
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

23. Other Bacteria live symbiotically in the guts of animals or elsewhere in their bodies.
For example, bacteria in your gut produce vitamin K which is essential to blood clot formation.
Still other Bacteria live on the roots of certain plants, converting nitrogen into a usable form.
E.coli on small intestines

24. Examples of Bacterial Pathogens
Salmonella
E. coli O157:H7
What shape are these bacteria? Cocci, bacilli, or spiral?
Staphylococcus aureus
Campylobacter jejuni
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

25. Kingdom Protista

26. Protista can be Pathogens
The Protista kingdom includes Algae, and Protozoans. They may have features like those of plants, animals, and fungi. They may be single celled or multicellular.

27. Protist can reproduce sexually or asexually
Meiosis
Budding and Fission

28. Common Protista Pathogens
Sporozoan – lives in blood and may cause malaria.
Trypanosome – lives in blood and may cause sleeping sickness.
Entamoeba histolytica – lives in the intestines andd can cause severe diarrhea.

29. Groups are based on movement . This includes movement by
How do they move ?
Groups are based on movement . This includes movement by
flagella, cilia, pseudopods .
false feet’
Hair like
structure
Streaming
cytoplasm
Whip like
structure

30. Viruses

31. What are Viruses?
Viruses and smaller than bacteria and much smaller than eukaryotes.
They consist of a shell made of protein and lipid which protect the genetic material inside.
They are not alive and none are helpful.

32. How do Viruses reproduce?
Viruses cannot reproduce or express their genes without the help of a living cell. Once a virus has "infected" a cell, it will “control" the cell's ribosomes, enzymes and much of the cellular machinery to reproduce. Viral reproduction produces many, many progeny, that when complete, leave the host cell to infect other cells in the organism.

33. How do Viruses reproduce?

34. Diseases cased by Viruses
Avian or Bird Flu
Swine Flu
Meningitis
Mononucleosis
Warts
Hepatitis
Bronchiolitis
Colorado Tick Fever
Encephalitis
Common Cold
HIV-AIDS
Influenza
Measles (Rubella)
Mumps
Polio
Rabies
Smallpox
Hepatitis
Herpes

35. Fungi

36. What is a Fungi?
Fungi are Eukaryotic heterotrophs and are unicellular and multicellular
Some live as saprophytes (live on rotting organic matter)
They perform a crucial role in nature by decomposing dead organisms
Some live in a mutually beneficial symbiotic relationship

37. How do Fungi Reproduce Asexually They produce spores Sexually
Budding – Buds that break of from the parent and produce an identical copy
Meiosis – sharing DNA wit similar fungi

38. Examples of Fungi molds yeasts Mushrooms mildews
Yeast: Candida albicans
mildews

39. How can I avoid getting sick from pathogens?
Wash your hands often so you won’t transfer bacteria to your mouth or food
Warm water with soap for 20 seconds, rub hard between fingers and nails
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

40. How can I avoid getting sick from pathogens?
Cook food thoroughly to kill any pathogens that may be in your food
Store food properly to limit pathogen growth
Cold temperatures (40F)
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

41. Antiseptic vs. Disinfectants
Controlling Bacteria
Antiseptic vs. Disinfectants
Antiseptic- chemicals that kill bacteria on living things
means – “against infection”
Examples: iodine, hydrogen peroxide, alcohol, soap, mouthwash
Disinfectants- stronger chemicals that destroy bacteria on objects or nonliving things

42. Review Bacteria are prokaryotic and unicellular.
Bacteria have cell walls.
Bacteria have circular DNA called plasmids
Bacteria can be anaerobes or aerobes.
Bacteria are heterotrophs or autotrophs.
Bacteria are awesome!

43. Review Bacteria, Fungi, and Protista are living organisms
Most are harmless
A few are pathogens that make you sick
You can reduce the risk of getting sick by washing your hands and handling food properly.
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

44. Review Shapes of Bacteria

45. Bacteria can reproduce sexually by conjugation or asexually by binary fission.

47. The Gram stain has four steps:
1. crystal violet, the primary stain: followed by
2. iodine, which acts as a mordant by forming a crystal violet-iodine complex, then
3. alcohol, which decolorizes, followed by
4. safranin, the counterstain.

49. Is this gram stain positive or negative? Identify the bacteria.

50. Is this gram stain positive or negative? Identify the bacteria.