Hazards to

Food Safety

M.Aldana 2015

Learning Objectives

• Identify and give examples of each of the

three main types of foodborne hazards

• Discuss how infections, intoxications, and

toxin-mediated infections cause foodborne

illness.

• List the factors that promote bacterial

growth

• Identify the Temperature Danger Zone

Learning Objectives

• Explain how temperatures in the danger

zone affect bacterial growth

• Identify the major types of potentially

hazardous foods and the characteristics

that are common to this group of foods.

Foodborne Illness

General Symptoms of

Foodborne Illness• Headache

• Nausea

• Vomiting

• Dehydration

• Abdominal Pain

• Diarrhea

• Fatigue

• Fever

Classification of Foodborne

Illness• Foodborne Infection

• Intoxication

• Toxin-mediated Infection

Foodborne Infection

• Happens when a

disease causing

organism is eaten

along with the food

• After ingestion, the

organism burrows into

the lining of the

victim’s digestive tract

and begins to grow in

number.

Intoxication

• Happens when a living

organism multiplies in or on

a food and produces a

chemical waste or toxin.

• Also, when an individual

consumes food that contains

man-made chemicals such

as cleaning agents or

pesticides.

Toxin-mediated Infection

• Happens when a living

organism is consumed

with food. Once inside

the human body, it

produces a toxin that

causes the illness.

Onset Time

• The number of hours

between the time the

person eats a

contaminated food and

when they first show

signs of the disease.

• Foodborne illnesses

have different onset

times.

Onset Time

• The onset time varies depending on

factors such as: age, health status, body

weight, and the amount of contaminant

ingested with the food.

High Risk Population

• These individuals’ symptoms and duration

of foodborne illness can be much more

severe and even life threatening.

Foodborne Hazards

• Refers to Biological, Chemical or

Physical Hazards that can cause illness

or injury when consumed along with the

food.

Biological Hazards

• Include bacteria, viruses, parasites and

fungi.

• These organisms are very small and can

only be seen with the aid of a microscope.

Biological Hazards

• Many of these organisms occur naturally

in the environment where the foods grow.

• Most are destroyed by adequate cooking,

and numbers are kept to a minimum by

proper cooling during distribution or

storage.

Chemical Hazards

• Are toxic substances that may occur

naturally or be added during the

processing of the food.

Physical Hazards

• Are hard or soft foreign objects in food that

can cause illness or injury.

Bacteria

Bacteria

• The most important biological foodborne

hazards for any food establishment.

• Bacteria are reported in more cases of

foodborne illness than any other hazard.

Bacteria

• Vegetative State – cells grow, reproduce

and produce wastes

• Spore State – some bacteria have the

ability to form spores. Spores help bacteria

survive when their environment is too hot,

cold, dry, acidic or when there is not

enough food.

Spore Forming

Vegetative Cells

(Optimal Conditions)

Spores

(Stress Conditions)

Reproduce Yes No

Grow Yes No

Produce Toxin Yes No

Resistant to

stress

No Yes

Harmful if eaten Yes No

Bacteria

• Spoilage Bacteria – degrade or break

down food so that they look, taste and

smell bad.

• Pathogenic Bacteria – are disease

causing microorganisms that can make

people ill if they or their toxins are

consumed with food.

Bacterial Growth

• Bacteria reproduce

when one bacterial

cell divides to form

two new cells. This

is called Binary

Fission.

Bacterial Growth

• Bacteria needs six basic conditions in

order to multiply.

Four Phases

• Lag Phase

• Log Phase

• Stationary Phase

• Decline Phase

Lag Phase

• Phase in which bacteria exhibit little or no

growth.

• Lasts only a few hours at room

temperature.

Log Phase

• Logarithmic or Exponential Growth

• Bacterial growth is very rapid during the

log phase with bacteria doubling in

numbers every few minutes.

Stationary Phase

• The number of new bacteria being

produced equals the number of organisms

that are dying off during this phase.

Decline Phase

• Bacteria die off rapidly because they lack

nutrients and are poisoned by their own

toxic wastes.

FATTOM

• Food

• Acid

• Temperature

• Time

• Oxygen

• Moisture

Source of Food

• Most bacteria prefer foods that are high in

protein or carbohydrates like meats,

poultry, seafood, dairy products, and

cooked rice, beans, and potatoes.

Acidity

• The symbol pH is used to designate the

acidity or alkalinity of a food. (range 0-14)

• Acidic foods have pH of less than 7.0

• Foods with pH above 7.0 is alkaline

• Bacteria grow best in foods that have 4.6-

7.0 pH

Temperature

• Temperature

Danger Zone – 41’F

to 135’F

• All bacteria do not

have the same

temperature

requirements for

growth.

Psychrophilic Bacteria

• Cold-loving bacteria

• Grow within a temperature range of

32’F(0’C) to 70’F(21’C)

Mesophilic Bacteria

• Grow at temperature range of 70’F(21’C)

to 110’F(43’C) with most rapid growth at

human body temperature of 98.6’F(37’C)

Thermophilic Bacteria

• Heat-loving bacteria

• Grow best at temperature above

110’F(43’C)

Temperature Abuse

• Is the term applied to foods that have not

been heated to a safe temperature or not

kept at proper temperature.

Time

• The rule of thumb in the foodservice

industry is that bacteria need about 4hours

to grow to high enough numbers to cause

illness.

Oxygen

• Aerobic bacteria – must have oxygen to

grow

• Anaerobic bacteria – cannot survive

when oxygen is present

• Facultative Anaerobic bacteria – can

grow with or without oxygen

• Microaerophilic organisms – specific

oxygen requirements usually 3%-6%

Moisture

• Water Activity (Aw) a measure of the

amount of water that is bound to the food

and is, therefore available for bacterial

growth.