water activity (Aw) --- A measure of the availability of free water for biological functions of microorganisms. These biological functions include transport of nutrients, removal of waste material, synthesis ofcellular materials, and ability to carry out enzymatic reactions.
pasteurization --- low heat (below 100C) which destroys all vegetative cells of pathogens and approxamately 90% of spoilage organsims (yeasts, molds, bscteria). Used for milk, liquid whole eggs, fruit juices, etc.
organic acids --- acids used in food preservation which interferes with normal metabolic functions of microorganisms and thus decreases or stops their growth. Examples include acetic, propionic, lactic, citric acids. Common organic acids all contain the carboxylic acid group.
pH --- measure of the hydrogen ion concentration
oxidation --- the addition of oxygen or the loss of hydrogen
reduction --- the loss of oxygen or gain of hydrogen
thermophiles --- organisms which grow from 45 - 70 C, with an optimum of 55 C.
mesophiles --- organisms which grow from 10 - 45 C, with an optimum of 35 C.
psycophiles--- organisms which grow from -5 to 20 C, with an optimum of 15 C.
1. List and/or recognize the reasons why foodborne diseases are a problem.
2. What are the traditional foodborne vehicles of disease?
3. What are the new foodborne vehicles of disease?
4. List 5 breaches in proper food handling procedures that are responsible for outbreaks of foodborne disease.
5. What are the extrinsic factors and the intrinsic factors in food that are responsible for food being such a hospitable medium for growth of microorganisms?
6. List and/or recognize the various methods (i.e., heat, addition of acids and control of pH) that are used to keep organisms from growing in food.
7. For each of the methods in question #6, list and/or recognize one procedure (given in class) for accomplishing that method and one example of a food for which that procedure may be used.
enterotoxin --- exotoxin that affects the intestinal mucosa
neurotoxin --- exotoxin that damages nerve tissue
lysozyme --- enzyme found in body secretions such as saliva that destroys bacterial cell walls
infection dose --- number of organisms needed to initiate infection in a host
protozoa --- unicellular, non-photosynthetic eukaryotes
cysts --- protective, dormant structure formed by some protozoa
central nervous system (CNS) --- brain and spinal cord
peripheral nervous system --- nerves which extend to and from brain and spinal cord to all parts of the body
sensory nerves (neurons) --- carry messages from sensory receptors of body to CNS
motor nerves (neurons) --- carry messages from CNS to a target organ, i.e., muscles
somatic nervous system --- controls the voluntary movements of the body
autonomic nervous system --- controls the involuntary, homeostatic activities of body’s internal organs and blood vessels
neurotransmitters --- chemical messengers that transfer impulses among nerves or from nerve to a target organ
spores --- reproductive structures produced by some bacteria and fungi which allow the organism to resist adverse environmental conditions
1. List the function of each of the following components of the gastrointestinal tract/digestive system:
2. List the normal defenses of the gastrointestinal tract against foodborne diseases.
3. List the ways organisms may circumvent the defenses in question #2 to cause disease.
4. List the 2 divisions of the nervous system. What comprises each?
5. What is the difference between the somatic nervous system and the autonomic nervous system?
6. Explain the difference between the somatic nervous system and the autonomic nervous system.
7. What are neurotransmitters?
8. Name 2 mechanisms of pathogenicity of organisms that cause foodborne disease.
9. List 2 organisms that produce toxins in food prior to consumption.
10. What is food poisoning?
11. What is the agent of botulism?
12. What foods may harbor C. botulinum? 13. What conditions must be present in order for C. botulinum to cause disease?
14. What are spores?
15. How does C. botulinum cause disease?
16. What are the symptoms of botulism?
17. What is the most common form of food poisoning?
18. What foods are associated with food poisoning due to Staphylococus aureus?
19. List the steps in a typical outbreak of food poisoning due to Staphylococcus aureus.
20. What are the symptoms of food poisoning due to S. aureus and how soon do they occur after consumption of the contaminated food?
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