Microbiology of Fermented Food Production ◾ 171
Fermentation Process
Foods can be fermented in three different ways, based on the sources of the desirable microorganisms: natural fermentation, back slopping, and controlled fermentation.
Natural Fermentation
Many raw materials used in fermentation (usually not heat treated) contain both desirable and
associated microorganisms. The conditions of incubation are set to favor rapid growth of the
desirable types and no or slow growth of the associated (many are undesirable) types. A product
produced by natural fermentation can have some desirable aroma resulting from the metabolism
of the associated flora. However, because the natural microbial flora in the raw materials may not
always be the same, it is difficult to produce a product with consistent characteristics over a long
period of time. Also, chances of product failure because of growth of undesirable flora and foodborne diseases by the pathogens are high.
Back Slopping
In this method, some products from a successful fermentation are added to the starting materials, and conditions are set to facilitate the growth of the microorganisms coming from the previous product. This is still practiced in the production of many ethnic products in small volumes.
Retention of product characteristics over a long period may be difficult because of changes in
microbial types. Chances of product failure and foodborne diseases are also high.
table 15.1 Fermented Food Groups and examples
Food Groups
Examples
Dairy products
Cheeses, yogurt, buttermilk, sour cream, dahi, kumiss, kefir,
acidophilus milk
Meat products
Salami, pepperoni, chorizo, thüringer, sausage, pickled meat, nahm
Cereal products
Breads, pancake, crackers, pizza, nun, idli, dosa, sour rice, miso
Fruits and
vegetable products
Pickled fruits, pickled vegetables, olives, sauerkraut, kimchi, aachar
Legume products
Tofu, fermented soymilk, tempe, soy sauce, koji, mizo, natto, papadam
Fish products
Bagoong, fish sauces, pickled fish, tarama, paak, mamoni, izushi
Beverages
Beer, wine, distilled spirits, coffee, cocoa, tea
Starch crop
products
Fermented products from potato, cassava, sweet potato, bananas,
plantains
Miscellaneous
products
Fermented eggs, ghee (from fermented cream), vinegar, red palm oil,
bongkrek, dage
Source: Adapted from Campbell-Plat, G., Fermented Foods of the World, Butterworths, London,
1987, p. xi.
Fermentation Process
Foods can be fermented in three different ways, based on the sources of the desirable microorganisms: natural fermentation, back slopping, and controlled fermentation.
Natural Fermentation
Many raw materials used in fermentation (usually not heat treated) contain both desirable and
associated microorganisms. The conditions of incubation are set to favor rapid growth of the
desirable types and no or slow growth of the associated (many are undesirable) types. A product
produced by natural fermentation can have some desirable aroma resulting from the metabolism
of the associated flora. However, because the natural microbial flora in the raw materials may not
always be the same, it is difficult to produce a product with consistent characteristics over a long
period of time. Also, chances of product failure because of growth of undesirable flora and foodborne diseases by the pathogens are high.
Back Slopping
In this method, some products from a successful fermentation are added to the starting materials, and conditions are set to facilitate the growth of the microorganisms coming from the previous product. This is still practiced in the production of many ethnic products in small volumes.
Retention of product characteristics over a long period may be difficult because of changes in
microbial types. Chances of product failure and foodborne diseases are also high.
table 15.1 Fermented Food Groups and examples
Food Groups
Examples
Dairy products
Cheeses, yogurt, buttermilk, sour cream, dahi, kumiss, kefir,
acidophilus milk
Meat products
Salami, pepperoni, chorizo, thüringer, sausage, pickled meat, nahm
Cereal products
Breads, pancake, crackers, pizza, nun, idli, dosa, sour rice, miso
Fruits and
vegetable products
Pickled fruits, pickled vegetables, olives, sauerkraut, kimchi, aachar
Legume products
Tofu, fermented soymilk, tempe, soy sauce, koji, mizo, natto, papadam
Fish products
Bagoong, fish sauces, pickled fish, tarama, paak, mamoni, izushi
Beverages
Beer, wine, distilled spirits, coffee, cocoa, tea
Starch crop
products
Fermented products from potato, cassava, sweet potato, bananas,
plantains
Miscellaneous
products
Fermented eggs, ghee (from fermented cream), vinegar, red palm oil,
bongkrek, dage
Source: Adapted from Campbell-Plat, G., Fermented Foods of the World, Butterworths, London,
1987, p. xi.