Principles of Food Sanitation

Tests for Sanitizer Strength

To increase sanitizer effectiveness, a num-
ber of tests have been devised to determine
the concentration of the sanitizer being
tested. The tests to be discussed are recom-
mended by the FDA.

Chlorine Sanitizers

The following methods can be used to
determine chlorine concentration in the san-
itizer being tested:

1.Starch iodide method (iodometric).

This is a titration test in which chlorine

displaces iodine from potassium iodide

in an acid solution and forms a blue

color with starch. Decolorization

occurs by the addition of standard

sodium thiosulfate. This test is gener-

ally used to measure high residuals.

2.O-tolidine colorimetric comparison.

This is a test in which a colorless solu-

tion ofo-tolidine is added to a chlorine

solution. An orange-brown-colored

compound proportional to its concen-

tration is produced and is compared

with a standardized color.

3.Indicator paper test. This is rapid test of

limited accuracy in which test papers,

usually impregnated with starch iodide,

are immersed. The developed color is

compared with a standard.

Iodophors

Although iodophors have a built-in color
indicator that is relatively accurate, color
comparative kits and other kits are available
for testing.

Quaternary Compounds

There are several satisfactory tests for
determining concentration of these com-
pounds. Some reagents are available in
tablets, and others use test papers by which a
color comparison is made.

Summary

Sanitizers are applied to reduce the patho-

genic and spoilage microorganisms of food

facilities and equipment. Soils must be com-

pletely removed for sanitizers to function

properly.

The major types of sanitizers are thermal,

radiation, and chemical. Thermal and radia-

tion techniques are less practical for food

production facilities than is chemical sanitiz-

ing. Of the chemical sanitizers, the chlorine

compounds tend to be the most effective and

the least expensive, although they tend to be

more irritating and corrosive than are the

iodine compounds or the quaternary ammo-

nium compounds. Bromine compounds are

more beneficial for wastewater treatment

than for sanitizing cleaned surfaces, although

bromine and chlorine are synergistic when

combined. The quats are more restrictive in

their activities but are effective against mold

growth and have residual properties. They do

not kill bacterial spores but can limit their

growth. Acid-quat and chlorine dioxide sani-

tizers offer potential for the control of

L. monocytogenes, and ozone is being evalu-

ated as a chlorine substitute. Glutaraldehyde

can be incorporated as a sanitizer for con-

veyor lubricants used for food operations.

Various tests are available to determine the

concentration of sanitizing solutions.

Study questions

1. What are the advantages and disadvan-
   tages of hot water as a sanitizer?


2. What factors contribute to the effec-
   tiveness of a sanitizer?


3. How is chlorine dioxide produced for
   use in a food facility?


4. What are the advantages and disadvan-
   tages of chlorine as a sanitizer?

188 PRINCIPLES OFFOODSANITATION