lesson 7

a. Incubation period- if pathogens in food are swallowed delay before symptoms begin.

b. microbes pass through the stomach into the intestine, attach to the cells lining the intestinal walls, and begin to multiply.

c. Foodborn intoxications are caused by toxins produced by growing microbes; you eat food containing the toxin and you get sick. Illness onset may be within 30 min, sonner tht for a food infection, because the tocin is already in the food. There can be nausea abdominal cramps and violent omitting as your body attempts to get rid of the poison. Usually lasts less the 24 hours.

d. Attack of the microbes
a. Avoiding bacterial infections should be easy. But illness does occur because
i.Microbes are found everywhere
ii. Bacterial cells are protected by cell wall and capsule
iii. Cells are often motile (flagella
iv. Bacterial cells produce toxins and enzymes

a. An outbreak of foodborne illness occurs when a group of people consume the same contaminated food and 2 or more of them get sick. Seafood produces the most outbreaks

b. Ten causes of foodborne illness
i. Bacterial pathogens: Salmonella, campylobacter, listeria monocytogenes, E. Coli O157:H7, colostridium botulinum and staphylococcus aureus
ii. Parasitic diseases: trichina spirallis
iii. Viruses: norovirus, hepatitis A
iv. Prion diseases: scrapie, BSE (mad cow), CWD(chronic wasting disease), and variant Creutzfeld-jakob Disease (CJD)

# illnesses: 1.4 million

# deaths: 582 deaths

Foods: contaminated foods are often of animal orgin: beef, poultry, milk, or eggs but begetables may also become contaminated.

Salmonella Enteritidis ? food source: Eggs

2 ways eggs can be contaminated with Salmonella
1. Gecal bacteria on the surface

2. transfer of salmonella from the ovaries of infected laying hens into the yolk of an egg (transovarian infection). The yolk is a rich source of nutrients and the body of a hen is 102 F supports rapid growth of salmonella, a mesophile.



Who was Mary Mallon and what illness did she cause?
Cook and had Salmonella typhi. A carrier is an infcced persn showing know signs. Mary spread the disease by not washing her hands

# illnesses: 2.4 million

# deaths: 24


Primary food source: Poultry, unpasteruzied milk, occasionally with raw meat.


Guillian Barre syndrome defined: when a person?s immune system is ?triggered? to attack the body?s ow nerves, and can lead to paralysis that lasts several weeks and usually requires intensive care. Happens in 1 in every 1000.



Cross contamination defined: cutting poultry meat on a cutting board and not washing it and then cutting raw vegetables.

# illnesses: 2,518

# deaths: 20% die

Primary food sources: found in soil and water-borne. Found in raw milk, deli meats, soft cheeses.


Growth temperature: It?s a psychrotroph so can survive in refrigerated.

General notes about this bacterium: The organism is found on most cattle farms and is commonly found in petting zoos. Its is a fecal pathoge, with muscle being contaminated during slaughter. Only takes less then 10 to effect.

# illnesses: 75,000 illnesses

# deaths:61 deaths

Primary food source: linked to raw ground beef.

Food source: improperly canned foods , chopped garlic, oil, cile peppers, femented fish

Life cycle of a spore-forming bacterium- The vegetative cell forms a spore in response to stress. The vegetative cell is destroyed, but the spore survives. Under proper conditions, the spore germinates and a new vegetative cell is formed.


Conditions for production of botulinum toxin: anaerobic enviroment, high pH and at warm temperatures.


Botulism poisoning- disease from clostridum botulinum
a. 25 each year and kills 50%-100%
b. classic symptoms: muscle weakness, double or blurred vision, dropping eyelids, slurred speech ,difficulty swallowing and dizininess.
c. paralysis of the respiratory tract leads to death.
d. An antioxin can be administered


Infant botulism : caused by consuming the spores of botuilnum bacteria.
a. Linked to the presence of botulism spores in dust and to feeding honey to children under one year of age.

a. 25% of humans are carriers of this bacterium and 200,000 persons get sick each year to foodborne Staph intoxication.

b. Staph produces a heat-stable toxin in food.

c. Salt tolerate

Food sources: sliced meat, pastries and sandwiches

a. Parasitic roundworm

b. found in raw meat

c. takes 3 forms
i. larvae
ii. mature round worm
iii. cyst (encapsulated worm)

a. Caused by hepatitis A virus

b. Fecal-oral route

c. Takes 4 weeks

d. Symptoms: fatigue, adominal pain, nausea, fever, and jaundice.

e. Peak infectivity occurs 2 weeks before the onset of most symptoms.

a. Fecal oral route

b. Illness beginning 24-48 hours after exposure.

c. Brief but severe with projectile omitting and profuse watery diarrhea.

d. Effects cruise ships

transfer of salmonella from the ovaries of infected laying hens into the yolk of an egg (transovarian infection

is the temperature range where bacteria grow most rapidly, 40-140 degrees.

A carrier is an infcced persn showing know signs

cutting poultry meat on a cutting board and not washing it and then cutting raw vegetables.

red blood cells are destroyed and the kidney fail

an infection caused by a type of staph that is resistant to many commonly prescribed antibiotics. Skin infection

i. Scrapie (sheep)

ii. Bovine spongiform encephalopathy (cattle)

iii. Chronic wasting disease (deer and elk)

iv. Creutzfeldt-Jakob diseases (humans)

a. ground beef from spinal colum
b. muscle tissue contaminated with brain matter during slaugher, some intestinal material and so forth

crossing the species barrier: A disease I cattle has moved to humans

Variant CJD

a. median age is 28

b. duration is 13-14 months

c. psychiatric/ beabioral symptoms

d. 1/500,000