MIXED CULTURE VERSUS PURE CULTURE FERMENTATIONS: WHICH IS EASIER?

Traditionally in microbiology and biotechnology lectures and practicals, there seemed to be a slant towards pure culture practicals. In real life, microorganisms in nature do not often occur in pure culture communities. Microbial ecology generally involves the interactions of mixed cultures and their environment.
No amount of pure culture data studies will give the accurate picture what really happened to microorganisms in nature! At best, pure culture will perhaps help in giving understanding as to what really happened in nature
Mixed culture studies seem to be avoided by most microbiologists especially those involved in the studying of microbial physiology and biochemistry of microorganisms. Don’t believe me? Just read a few popular microbiological or biochemical textbooks!
Although the study of pure culture has its own strength especially in the production of fermentation products by single pure microorganism, its success is more attributed to the ability of microbiologists to generate pure cultures or aseptic techniques. To these microbiologists the presence of other microorganisms in the industrial process is more a minus minus factor and regarded as a microbial contaminant which will complicate the fermentation process and affect its productivity
In my personal experience it is far more difficult to understand and control a mixed culture fermentation compared to doing a pure culture fermentation!
There are many parameters which affect the mixed culture fermentation process and slight change in one operating parameter will result in the change in the components of the mixed culture population dynamics….. To put it simply, the process may easily run out of control.
In pure culture fermentation this is not the problem. Pure culture fermentation are more stable and the only goal is to obtain the optimum fermentation process to produce the best yield possible!
The principles of mixed culture fermentation are often complicated by:
1 Selection of steady environment
2 Ensuring stable substrate composition and delivery
Most that involve complex substrate will often see the formation of microbial succession which could be good or bad depending on the purpose of fermentation
Mixed culture metabolism too tend to change the environment that lead to microbial succession
This is one of the main reason in traditional mixed culture fermentation becomes further complicated when the scaling up is exercised!
Merry Christmas!


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THINGS THEY DON’T TELL YOU ABOUT FISH SAUCE (BUDU) FERMENTATION

In the first place let us get a few things straight. Fish sauce fermentation is the traditional fermentation of many countries, especially those in South East Asian countries. It is a grave error to regard the fish fermentation as the traditional right or heritage of a particular country or state.
According to Wikipedia the Romans have been known to produce fish sauce called garum as part of their Greco Roman cuisine!!. The famous Lea Perrin sauce in typical British culinary is a fish sauce. The ingredients of a traditional bottle of Worcestershire sauce sold in the UK as "The Original & Genuine Lea & Perrins Worcestershire Sauce" are malt vinegar (from barley), spirit vinegar, molasses, sugar, salt, anchovies tamarind extract, onions, garlic, spice, and flavouring. The "spice, and flavouring" is believed to include cloves soy sauce, lemons, pickles and peppers.
I just can’t help laughing how emotional some readers are in claiming the “rights” to the fish sauce without doing research into the origin and diversity of fish sauce. Sometimes blind ignorance can have its place in this country!
While the use of fish sauce or budu is quite limited in Malaysia, this is not the case in Thailand or Vietnam where the fish sauce is almost in everything and regarded as the Magic elixir in their cooking. Fish sauce made in Thailand is easily available on the supermarket shelves that cater for Asian cooking. The bottled fish sauce looked very attractive especially with their golden brown colour, beautifully labeled and subjected to perfect advertising and marketing strategies that make the product successful.
When you buy a bottle of fish sauce in the market, the sauce looks golden brown and appealing. Everything is so hygienic and sanitary that you would not be able to appreciate how the fish sauce was manufactured. Gladly you will buy the bottle and use it frequently in cooking dishes to your family delight at the dinner table.
Little do you suspect that what you are enjoying is merely a rotting broth of decomposing fish with the added nutritional values contributed by flies and maggots!
There are certain things they will not tell or show you about fish sauce fermentation. Zimmerman of Bizarre Foods would probably faint or go into prolonged coma if he witness up close and personal how fish sauce are produced.
Coupled to this bottled product advertising approach the fish sauce companies make great effort to prove the sanitary quality of the production facilities especially in stressing:
1 The use of fresh fish or anchovies to be used as the fermentation substrate
2 Clean and hygienic bottling facilities
3 Use of scientific quality control such as GMP and HACCP and the use of advance analytical laboratories to monitor the production especially in downstream activities
What is not shown is the true facts of how the fish sauce is really fermented. They only show you the nice sanitized end products. They don’t show you the dirt and the grime of the fish sauce fermentation! (This is akin to the presentable chicken all clean and wrapped in the butchery area of the supermarket. You don’t see the slaughter! You don’t see the blood!)
Let us get the facts straight! Let us visit the “ground zero” of fish sauce fermentation!
1Fish sauce fermentation is a mixed culture fermentation which involves the action of multitudes of microorganisms
2 Fish sauce fermentation is still basically traditional fermentation even though it might be industrialized
3 The fermentation vats for fish sauce fermentation are often ceramic vats cement vats or even PVC vats operated in batch operations
4 The fermentation is natural and septic and occur over periods of months
5 There is poor quality or hygienic control during the fish sauce fermentation in the vats
6 The fish are left to rot and decompose over long periods of times under high concentrations of salts. At the end of the period the salt would have sucked out the water from the fish entrails or tissues
7 Periodically the vats are left open to expose it to air and sunlight to enhance fermentation or decomposition
8 Its not uncommon to see flies and maggots or larvae breeding in the vat while the fish sauce is fermenting. Urgghhh! It stinks! Its visually repulsive!
I often wonder how some of these fish sauce are GMP or HACCP compliance ?





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