Fundamental Food Microbiology, Third Edition - Fuad Fathir

CONTROL OF ACCESS (CLEANING AND SANITATION) 445
The frequency of cleaning depends on the products being processed and the
commitment of the management to good sanitation. From a microbiological standpoint,
prior microbiological evaluation of a product can give an indication about the
frequency of cleaning necessary in a particular facility. Cleaning of the equipment
is done either after disassembling the equipment or by the CIP system. Because of
its efficiency and lower cost, CIP cleaning has become popular. The system uses
detergent solutions at a high pressure. Because microorganisms can grow in some
detergent solutions, they preferably should be prepared fresh (not exceeding 48 h). 1–4
G. Sanitation of Food-Processing Equipment
Efficient cleaning can remove some microorganisms along with the soil from the
food contact surfaces, but cannot ensure complete removal of pathogens. To achieve
this goal, food contact surfaces are subjected to sanitation after cleaning. The methods
should effectively destroy pathogenic microorganisms as well as reduce total
microbial load. Several physical and chemical methods are used for sanitation of
food-processing equipment.
Physical agents used for sanitation of food-processing equipment include hot
water, steam, hot air, and UV irradiation. UV irradiation is used to disinfect surfaces
and is discussed in Chapter 38. Hot water and steam, although less costly and efficient
for destroying vegetative cells, viruses, and spores (especially steam) can be used
only in a limited way.
Chemical sanitizers are used more frequently than physical sanitizers. Several
groups of sanitizers are approved for use in food-processing plants. They vary greatly
in their antimicrobial efficiency. Some of the desirable characteristics used in selecting
a chemical sanitizer are effectiveness for a specific need, nontoxicity, noncorrosiveness,
no effect on food quality, easy to use and rinse, stability, and cost effectiveness.
Important factors for antimicrobial efficiency are exposure time,
temperature, concentrations used, pH, microbial load and type, microbial attachment
to surface, and water hardness. Microbial attachment has been discussed separately
(Appendix A). The mechanisms of antimicrobial action and the advantages and
disadvantages of some of the sanitizers used in food-processing plants are briefly
discussed here. Some sanitizers, designated as detergent sanitizers, can both clean
and sanitize. They can be used in a single operation instead of first using detergent
to remove the soil and then using sanitizers to control microorganisms. They are
also discussed here. 1–4
1. Chlorine-Based Sanitizers
Some of the chlorine compounds used as sanitizers are liquid chlorine, hypochlorites,
inorganic or organic chloramines, and chlorine dioxide. Chlorine compounds are
effective against vegetative cells of bacteria, yeasts and molds, spores, and viruses.
Clostridial spores are more sensitive to chlorine compounds than are bacilli spores.
The antimicrobial (germicidal) action of chlorine compounds is due to the oxidizing
effect of chlorine on the –SH group in many enzymes and structural proteins. In
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