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Food and Water Borne Pathogens Text questions: Chap 12: Crit Think 2; Self-Quiz #s 8-10, 12, 13, 16 Roles of Micro PowerPoint Presentation
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Food and Water Borne Pathogens Text questions: Chap 12: Crit Think 2; Self-Quiz #s 8-10, 12, 13, 16 Roles of Microbiologists in the Food Industry 1) Monitoring and controlling contamination 2) Developing control methodologies 3) Using microbes in food production

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slide1

Food and Water Borne Pathogens

Text questions: Chap 12: Crit Think 2;

Self-Quiz #s 8-10, 12, 13, 16

Roles of Microbiologists in the Food Industry

1) Monitoring and controlling contamination

2) Developing control methodologies

3) Using microbes in food production

Types of food-borne diseases

Food borne intoxicationsFood/water borne infections

Botulism E. coli (e.g., O157:H7)

Perfringens Salmonellosis

Staphylococcal Campylobacteriosis

Mycotoxins Cholera

rapid onsetslower onset

Incidence (/100,000) in 2005

from CDC

Food and Water Borne Pathogens

slide2

Food Intoxications:

Perfringens

Agent: Clostridium perfringens

obligate anaerobe

Reservoir: animal digestive systems

endospores common

Toxin: Enterotoxin

-- heat-labile

Institutional steam tables notorious

bulk food

Cook to at least 140OF

Chill rapidly

Symptoms

within 8-14 hours

pain, diarrhea

no nausea and vomiting

pass within 24 hour

Food and Water Borne Pathogens

slide3

Staphylococcal

Agent: Staphylococus aureus

Reservoir: Humans and animals

Toxin: enterotoxins

7 types identified

(genes often on plasmids)

heat-stable

50% inactivation at 100OC

Foods: inadequately refrigerated

-- custards and pastries

-- poultry and egg salads

-- creamy salad dressings

-- etc

symptoms

onset 1-6 hours

nausea, vomiting, diarrhea

pass within a few hours

What about the chicken & potato salads?

It’s not the mayo!

Dateline: Modesto CA, 1983

Cook prepared 3600 eggs for Easter hunt

boiled, dyed, and left at

room temperature for 3 days

300 children were afflicted

CDC investigation revealed:

cook had sores on his hands

dyed eggs with vinegar, which

softens & permeates shells

Don’t leave cooked eggs unrefrigerated!

Food and Water Borne Pathogens

slide4

Mycotoxins

  • Produceed by fungi
  • Ergot – Claviceps
  • Aflatoxins – Aspergillus flavus
  • -- heat stable
  • Foods typically affected
    • cereal grains, oilseeds, spices, tree nuts, fruits
  • Toxicity: LD50 = 0.5 - 10 mg/kg
  • -- endocrine effects
  • -- digestion
  • Acute: liver necrosis
  • Chronic:
  • -- suspected hepatic carcinogen
  • -- metabolites intercalate into DNA

1960 - UK

100,000 turkeys die

“Turkey X disease”

Contaminated peanut meal

1974 - NW India

~400 people affected (~110 died)

Traced to infested corn

-- unseasonable rains,

-- poor storage

-- poverty

Estimated 2-6 mg/d consumed for weeks

Food and Water Borne Pathogens

slide5

Food infections:

E. coli

Transmission: food and water

“Traveler’ diarrhea”

“Montezuma’s revenge”

“delhi belly”

“Don’t drink the water”

Reservoir: warm-blooded animals

including humans

Plasmid-borne enterotoxins

Hemolytic toxins can lead to

hemorrhagic colitis, kidney failure, etc.

Symptoms

diarrhea; cramping, bloody stools

Surface antigens

-- ‘O’ (lipopolysaccharide) & ‘H’ (flagellar)

(173) (56)

E. coli O157:H7

extremely virulent

5 cells enough

Dateline: Jan 1993, Pacific Northwest.

Jack-the-the-box restaurants serve

O157:H7 tainted hamburgers;

over 500 people become ill, 3 die;

$30 M awarded in lawsuits

Dateline: June 11-12, 1998, Marietta, GA

30 children swimming in a kiddie pool contract O157:H7. Conditions were listed from fair to critical.

Food and Water Borne Pathogens

slide6

Salmonellosis

Agent:Salmonella enteritidis

Reservoir: animal digestive systems

Foods: inadequately cooked

poultry & eggs

meats & dairy products

shellfood (raw!)

Symptoms

within 1-2 days

fever, nausea, diarrhea,

vomiting, headache

convalescence in ~ a week

Typhoid fever

Salmonella typhi

What about those baby turtles?

illegal to sell since 1975

Food and Water Borne Pathogens

slide7

Campylobacteriosis

Agent:

Campylobacter jejuni

microaerophile

reservoir: poultry

Symptoms

2-5 day incubation

diarrhea (bloody stool)

abdominal cramping

high fever (>104O)

Transmission: Foods (usually) & water

undercooked meats

contaminated milks and water

(farm runoff)

Very common

104 cases per year

possibly 2 x 106 go unreported

estimated 500 deaths/year

Food and Water Borne Pathogens

slide8

1O Water Borne:

Cholera

Agent:

Vibrio cholorae

reservoir: humans

Transmission: usually water

Symptoms

toxin effects large intestine

SEVERE diarrhea

untreated, mortality rates > 70%

Worldwide pandemic

Oral rehydration

therapy

Oral Rehydration Therapy

Oral rehydration solution can be approximated by adding to 1 L of water

8 tsp of table sugar

1/2 tsp of salt

1/2 tsp of sodium bicarbonate

(baking soda)

1/3 tsp of potassium chloride

Food and Water Borne Pathogens

slide9

Probiotics: Consuming bacteria to improve intestinal flora

Estimated > 500 types of bacteria present

How might digestive tract bacteria benefit health?

1) improve intestinal tract function

-- food digestion; lactose intolerance; reduce flatulence

-- replace microbes lost during antimicrobial therapy

-- e.g., lactinex

-- replace harmful denizens

2) improve immune function

-- reduce allergies “Hygiene hypothesis”

-- modulate immune response

-- protective immune responses

3) Reduces cancer risk?? (colon, bladder)

-- mutagen binding & detoxification

-- immune modulation

Probiotic bacteria

Lactobacillus, Bifidobacterium

yogurt; dietary supplements

Does it work?

Maybe, sometimes…

Normal microflora is relatively stable

In children not breast fed

Food and Water Borne Pathogens