This document discusses fermentation of vegetables, describing the process by which lactic acid bacteria like Lactobacillus convert sugars in vegetables into lactic acid, preserving them without cooking and making them more nutritious. It provides details on the fermentation of cabbage into sauerkraut through the action of coliform bacteria followed by Leuconostoc and then Lactobacillus. Finally, it outlines several methods of fermenting vegetables including using brine, lactic acid, and pit fermentation.

1. BIO 421 microbiology
Bhalram Bhimraj 08/0702/0462
Marvin Monize 08/0702/3495
Mikhel Naraine 08/0702/3721
Carrell Bansavatar 08/0702/0460
Atiya N’djelekulu 10/0702/1830

2. What is fermentation?
 General definition: An anaerobic cellular process in
which bacteria, yeast or other microorganisms convert
organic foods into simpler compounds, and chemical
energy (ATP)is produced.
 Fermentation in food processing: the conversion of
carbohydrates into alcohols and carbon dioxide or
organic acids by yeast, bacteria or a combination of
both.

3. What is a Vegetable?
 The Big question is , DOES IT HAVE SEEDS?
• If the answer is yes , Then technically ,you have a FRUIT
(Matured ovary of a plant and contain seeds)
• Some plants may produce a fruit but there are other parts
of the plant that are used as food, such as leaf and flowers,
these parts are termed the vegetable.
• One may say, a vegetable can be any of the edible part of a
plant, however these parts must not have seeds present.

4. Fermentation of vegetables;
definition
 Is a technique used, whereby Starches and sugars in
vegetables are converted into lactic acid by the many
species of lactic-acid-producing bacteria.
 This is done by bacteria present in the storage vessels and
on the surfaces of vegetables.

5. The genus Lactobacillus;
 Members are responsible for lacto-fermentation of
vegetables.
 They comprise of a genus known as lactobacillus.
These bacteria get their name (lacto) because they
are able to form lactic acid (from sugars).
 These are "friendly" bacteria that normally live in our
digestive, urinary, and genital systems without causing
disease. There are over 70 species recognised.
 Lactobacillus is very heterogeneous genus, encompassing
species with a large variety of phenotypic, biochemical, and
physiological properties. Most species of lactobacilli are
homofermentative, but some are heterofermentative.

6. Process of vegetable fermentation; using
cabbage to make sauerkraut
 The process of fermenting begins with washing and
cutting cabbages and mixing them with salt, herbs and
spices.
 The vegetables are then pounded until some of their
juices are released, then pressed tightly into an airtight
container.
 The salt mixes with the vegetable juice to create a
brine which inhibits the growth of putrefying bacteria
until the vegetables release enough lactic acid to
continue the preservation process, while creating
prime conditions for the growth of Coliform
bacteria, which are ubiquitous in the air.

7.  Coliform bacteria produce acids, lower the pH of the
kraut, and set the stage for Leuconostoc bacteria to
colonize the medium.
 The Leuconostoc bacteria lower the pH of the sauerkraut
further still, thus creating the conditions for Lactobacillus
to grow(Katz 2003).
 Lactobacillus adds the characteristic taste of lactic acid to
the food.
 Lactic acid can create a temporary equilibrium
state, which is the ultimate goal of food preservation via
fermentation. Refrigeration halts the fermentation process.

8. Brine salted fermented vegetables
Similar process to sauerkraut
method of fermentation
15-20% salt solution is
preferred
The salt concentration does not
fall below 12%

9. Non salted, lactic acid fermented vegetables
Does not involve the addition of salt
or brine
Sinki or other wilted fermented leaves
are non salted additives
This process relies on the rapid
colonisation of the food by lactic acid
producing bacteria
The process usually takes twelve days
at 30 degrees Celsius

10. Pit fermentations
This is an ancient method of preserving
starchy vegetables without the addition of
salt
The raw materials undergo an acid
fermentation within the pit, to produce a
paste like substance
Foods preserved in pits can last for
years without deterioration

11. Means of preservation which allows for
greater shelf-life
Apart from acting as a means of
preservation, it makes food easier to digest.
The fact that the fermented vegetables are
not cooked makes it more nutritious.
Makes food safer for consumption