Learning Objectives

Define key terms: Microorganisms, Pathogen, Toxin, Spoilage Microorganisms

Differentiate the types of pathogens Describe the growth curve of bacteria Enumerate the conditions of the growth

microorganisms

Disease-Causing Microorganisms and the Conditions They Need to Grow

Barriers for Controlling the Growth of Microorganisms

Microorganism Small living organism

Pathogen A disease-causing microorganism

Toxin Poison

Spoilage Microorganism Microorganism that causesspoilage, but not illness

Bacteria Viruses Parasites Fungi

Microorganisms That Can ContaminateFood and Cause Foodborne Illness

Living, single-celled Carried by food, water, humans and insects Can reproduce rapidly Some survive freezing Some form spores Some spoil food; others cause disease Some cause illness by producing toxins

Growth Stages of Bacteria

Bacterial Growth

What Microorganisms Need to Grow

Food Microorganisms require nutrients to grow

Proteins

Carbohydrates

Acidity Pathogenic bacteria grow well at a pH of 4.6 to 7.5

Raw Chicken 5.5–6.4

Egg Yolks 6.0–6.3

Butter 6.0–6.8

Temperature The Temperature Danger Zone(TDZ) = 41ºF to 140ºF (5ºC to 60ºC)

Most microorganisms grow well in the TDZ

Some survive and grow outside the TDZ

Time Pathogenic microorganisms can grow to high levels if they remain in the TDZ for more than four hours

Oxygen Microorganisms have differentoxygen needs for growth

Aerobic needs oxygen to grow

Anaerobic grows only when oxygen is absent

Facultative can grow with or without oxygen

Moisture Most potentially hazardous foods have a water activity of .85 or above

Raw Chicken and Butter Water Activities of .95–1.0

Barriers That Control the Growthof Microorganisms

Make the foodmore acidic

Raise or lowerthe temperature of the food

Lower the water activity

Lessen the time in the TDZ

DIAGRAMATIC SCHEME

Physical

S a lm o n e lla

L is te riam o n o cy to ge n e s

V ib rio sp p .

C a m p y lo ca c te rje ju n i

Y e rs in iae n te ro co lit ica

In fec tion

S ta p h y lo co ccu sa u re u s

C lo s trid iu mb o tu lin u m

B a c illu s ce re u s(em etic )

In toxica tion

B a c illu s ce re u s(d ia rrh e a l)

S h ige lla sp p .

C lo s trid iu mp e rfrin ge n s

E sch e rich ia co li0 1 5 7 H 7

Toxin -M ed ia tedIn fec tion

B ac teria V iru ses

M old s(in c lu d in g

m u sh room s)

Y eas ts

F u n g i P aras ites

Biological

F ood A d d itivesF lavors

C o lors

P reserva tives

D irec tly A d d ed

C lean in g C h em ica ls

P es tic id es

H eavy M eta ls

A n tib io tics

In d irec tly A d d ed F ood A lle rg en s

S eafood Toxin s

P lan t toxin s

F u n g a l Toxin s

N atu ra lly O ccu rin g

Chem ical

FOOD SAFETY HAZARDS

Foodborne Infections Result when pathogens grow in intestines after a person eats food contaminated by them

Foodborne Intoxications Result from eating food containing poisonous toxins

Foodborne Toxin-Mediated Infections Result from toxins produced by pathogens growing in the intestines

Salmonellosis Shigellosis Listeriosis Staphyloccocal food poisoning Clostridium perfringens Enteritis

Major Foodborne Illnesses Caused by Bacteria

Bacillus cereus gastroenteritis Botulism Campylobacteriosis E. coli O157:H7 EHEC Vibrio gastroenteritis Yersiniosis

Figure 21.2 Egg sizes

Egg Grades

SalmonellosisType of Illness: Infection, possibly toxin-mediated

ListeriosisType of Illness: Infection

Staphylococcal Food PoisoningType of Illness: Intoxication

Clostridium perfringensType of Illness: Toxin-mediated infection

BotulismType of Illness: Intoxication

E. coli O157:H7 EHECType of Illness: Toxin-mediated infection

Can’t reproduce outside a living cell Usually contaminate food through poor personal hygiene May survive freezing and cooking Contaminate food and water

Hepatitis A Norwalk Virus Gastroenteritis Rotavirus Gastroenteritis

Major Foodborne Illnesses Caused by Viruses

Hepatitis AType of Illness: Infection

Norwalk Virus GastroenteritisType of Illness: Infection

Parasites Need to live in or on a host organism in order to survive

Host

Person Animal Plant

Freeze properly Cook to proper temperatures Avoid cross-contamination Use sanitary water supplies Wash hands properly

Keys to Prevention

Trichinosis Anisakiasis Giardiasis Toxoplasmosis Intestinal Cryptosporidiosis Cyclosporiasis

Major Foodborne Illnesses Caused by Parasites

Trichinosis

also called trichinellosis, or trichiniasis, is a parasitic disease caused by eating

raw or undercooked pork or wild game infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm.

Major Foodborne Illnesses Caused by Parasites

Anisakiasis

is a genus of parasitic nematodes, which have a life cycle involving fish and marine mammals.

Major Foodborne Illnesses Caused by Parasites

Gardiasis

(discovered by DR James de Silva) in humans is a diarrheal infection of the small intestine by a single-celled organism called Giardia lamblia. Giardiasis occurs worldwide with a prevalence of 20–30% in developing countries.

Major Foodborne Illnesses Caused by Parasites

Giardia lamblia cell

Toxoplasmosis

is a parasitic disease caused by the protozoan Toxoplasma gondii. Up to one third of the world's human population is estimated to carry a Toxoplasma infection. Ingestion of raw or partly cooked meat, especially pork, lamb, or venison containing Toxoplasma cysts.

Major Foodborne Illnesses Caused by Parasites

Protozoan T. gondii

Intestinal Cryptosporidiosis also known as crypto, is a parasitic disease caused by Cryptosporidium, a protozoan parasite. It affects the intestines of mammals and is typically an acute short-term infection. It is spread through the fecal-oral route, often through contaminated water

Major Foodborne Illnesses Caused by Parasites

Cryptosporidium muris

Cyclosporiasisis an infection with the protozoan Cyclospora cayetanensis, a pathogen transmitted by feces or feces-contaminated fresh produce and water. Outbreaks have been reported due to contaminated raspberries. It is not spread from person to person.

It can be a cause of diarrhea for travelers.

Major Foodborne Illnesses Caused by Parasites

Cyclospora cayetanensis

TrichinosisType of Illness: Infection

AnisakiasisType of Illness: Infection

Fungi

Molds Yeasts Mushrooms

Fungi Commonly cause food spoilage, not illness

Foodborne Infections Result when pathogens grow in intestines after a person eats food contaminated by them

Foodborne Intoxications Result from eating food containing poisonous toxins

Foodborne Toxin-Mediated Infections Result from toxins produced by pathogens growing in the intestines

Prepare an outline for a discussion of the four types of microorganisms. Include examples of what microorganisms need to survive and grow. Highlight the conditions managers have the most influence over.

Challenge participants to create a list of foods high in acid and another list of highly alkaline foods. Reward the participant who comes up with the most examples and have him or her share the list with the class.

Create a blank handout of a thermometer and have participants indicate the space for the temperature danger zone.