All raw foods whether originating from land or from the sea harbor bacteria which will eventually cause spoilage unless they are controlled or destroyed. Sterilization kills all bacteria. Pasteurization can kill many bacteria of public health significance, but not all bacteria.

From a consumer viewpoint, pasteurized foods are desirable because the resulting product resembles that of the fresh food. However, they must be held at refrigerated storage below 38"F. They can be stored at this temperature from a few days to several months depending upon the product. Pasteurized milk, cheese, wine etc have had a place in the family larder for many years, having been accepted by most consumers.

Pasteurization means that a food has been heated sufficiently to destroy the vegetative forms of bacteria, and many of the spores of some bacteria, both pathogenic (disease-producing) and non-pathogenic. The active vegetative bacterium can change into a dormant spore form when encountering unfavorable living conditions. This spore can withstand extreme heat and cold. Consider the spore as a very hardy plant seed. When a spore germinates under a favorable environment it is the same original vegetative bacterium continuing into its new growth phase.

Pasteurization is designed to kill bacteria and spores that can cause food poisoning. This type of food poisoning is called Botulism and is caused by a powerful toxin produced by bacteria known as Clostridium botulinum. This is a very deadly toxin. Seven types of C. botulinum. are recognized and classified by the letters A through G. The types are differentiated by the nature of the toxin produced. Botulism outbreaks due to type E have come from seafoods. Luckily, these spores are much less resistant to heat than all the others. (Illustration represents bacterial spores.)

The pasteurization of fishery products is limited almost entirely to crabmeat. George Clifford Byrd, a bacteriolgist and a native son of Crisfield on the Eastern Shore of Maryland USA, patented a process in 1951 to extend the shelflife of crabmeat to about six months, retaining essentially the same qualities as that of freshly picked crabmeat from steam-cooked crabs. His process established the water bath method of pasteurization, still in use today.

The pasteurization process involves placing the hermetically sealed cans in a 190"F water bath. The cans are held submerged in the bath for 110 minutes until the center temperature in the cans reaches 185"F and held there for three minutes. The cans are then transferred to an ice water bath and held there until the center temperature is 50"F. The cooled cans are then stored in a refrigerated warehouse at 35"F (range 32"-38"F). These cans can be stored at this temperature for several months.

Since this is a pasteurized, and not a sterilized, product it is extremely important the cans remain refrigerated until consumed. One would not think of taking a quart of pasteurized milk out of the refrigerator and placing it on the kitchen counter and leaving it there for several hours. Would one? Certainly not!!!