IT REQUIRES 'SKILL' TO SPOIL FERMENTED FOOD

(PICTURE TAKEN FROM WWW.CCC.GOVT.NZ)
While it is generally accepted that food fermentation is food preservation, but in the serious context food fermentation is not truly a method of food preservation. This is in the view when food materials are undergoing fermentation process, it is being acted upon by various types of microorganisms that hydrolyze and degrade the food substrate as their source of their energy.

The preservation aspects of food fermentation lies in the fact that as consequences of fermentation these microorganisms produce fermentation products which are acidic which will retard the growth of other microorganisms.

If this acidification process continue even the fermentative microorganisms which produce the organic acids will ultimately retard the fermentative microorganisms themselves.

In view of the preservative action of the fermentation products in inhibiting spoilage microorganisms from proliferating in the fermented food, why do spoilage of fermented food occur?

Spoilage of fermented food occurs because often the fermentation conditions are not strictly maintained. For example exposure to air or oxygen during the process of fermentation allows other facultative or aerobic microorganisms to thrive.

In pickling such as sauerkraut fermentation where the salt content is high would under aerobic conditions allow fungus to grow on substrate exposed to oxygen. It is important therefore that the salt concentration is maintained and not diluted as by then the lactic acid bacteria will not be to compete effectively against other microbial contaminants

Changes in ph by exposure to oxygen will allow the change in microbial succession to occur

In the case of tempe, the so called food spoilage is not really food spoilage as it does not involve microbial contaminants but merely the fungi sporulating to give it a dark appearence






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