SafeFood Lesson 4 Page 3

Introduction Lesson 1
What's
bugging
you?
Lesson 2
What are
Consumer
Control
Points?
Lesson 3
Where is the
DANGER
ZONE?
Lesson 4
Who is
FAT TOM?

Contact
Glossary
References

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Food Safety Lessons Introduction Lesson One: Whats Bugging You? Lesson Two: What are Consumer Control Points? Lesson Three: Where is the Danger Zone? Lesson Four: Who is FAT TOM? Glossary of Terms Food Safety References Contact the Food Safety Project Team

Lesson Four: Who is FAT TOM?
(continued)


A
is for Acidity
pH scale

The degree of acidity or alkalinity (base) of a substance is measured by its pH. pH is measured on a scale from 0 to 14.0. An environment with a pH of 7.0 is exactly neutral. Foods with a pH below 7.0 are acidic; a pH above 7.0 is alkaline. The lower the pH, the higher the acidity; the higher the pH, the lower the acidity.

Bacteria grow best in an environment that is neutral or slightly acidic. Most bacterial growth is inhibited in very acidic conditions. That is why acidic foods, like vinegar and fresh fruits (especially citrus), seldom provide a favorable climate for pathogenic bacteria. Most bacteria will not grow at pH levels below 4.6 because the environment is too acidic. Microorganisms thrive in a pH range between 6.6 and 7.5.

 


Copyright 1997-2007 Food Safety Project, Iowa State University Extension