1-14. COMMERCIAL STERILIZATION
Commercial sterilization of low-acid food is that process by which all Clostridium
botulinum endospores and all other pathogenic microorganisms are destroyed, as well
as microorganisms which could produce spoilage under conditions of normal,
nonrefrigerated storage and distribution in sealed containers. Some bacteria produce
endospores of extremely high heat resistance. These cannot be destroyed without
processing to such a high degree that the product would be unmarketable. Fortunately,
these bacteria are not pathogenic and are unable to germinate and cause spoilage at
temperatures below 100oF (38oC).
1-15. COOLING
After the heat processing, the cans are cooled. This is done rapidly to prevent
undue softening of the texture or change in color of the product. One of the following
two methods is used:
a. Air Cooling. Cans are piled in rows in a well-ventilated, specially designed
warehouse that has ample space for efficient air circulation. The heat is dissipated into
the surrounding air. This method has a slower loss of heat than the water-cooled
method.
b. Water Cooling. There are several kinds of water cooling, based on one of
two procedures. Cold water may be admitted to the retort after the processing is
complete, or the cans may be removed from the retort and conveyed through tanks or
showers of cold water. Large sizes or irregular-shaped cans must be pressure-cooled
in a closed retort to avoid undue strain on the containers.
1-16. PARTS OF A CAN
The parts of a can may be noted in Figure 1-9. Most of the parts identified have
been discussed in earlier paragraphs. The parts are: the side seam, the body, the
bead, the key tongue, the score, the can end, the double seam, the countersink, the
expansion ring, and the can code.
MD0708
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