Usages of bacteria in food industries

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Aryan Aditya Nanda
North Point School
Standard – VIII
Section - (B)
Roll No – 20
Uses of Bacteria
in
Food Industry

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INTRODUCTION
Democritus Leucippus
Democritus Leucippus
 Bacteria : Bacteria are unicellular organisms belonging
to the prokaryotic group where the organisms lack a few
organelles and a true nucleus”
 One of the very first organisms to evolve on earth was
probably a unicellular organism, similar to modern
bacteria. Ever since then, life has evolved into a multitude
of life forms over many millennia. However, we can still
trace our ancestry back to this single-celled organism.
List of Bacteria used in Food Industry:
 Lactobacillus
 Acetobacter
 Aspergillus
 Streptococcus and Bacillus
Classification of Bacteria
Bacteria can be classified into various categories based on
their features and characteristics. The classification of
bacteria is mainly based on the following:
 Shape
 Composition of the cell wall
 Mode of respiration
 Mode of nutrition

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Use of Bacteria in Making Curd
 The major bacterias used for making curd as below :
 Lactobacillus bulgaricus
 Lactobacillus acidophilus
 Curd is cultured milk. To make curd,milk is firstly heated to
around 85°C. Heating makes sure any unwanted bacteria are
killed, and it also helps to change the structure of the milk proteins,
allowing them to set smoothly.
 After heating, the milk is cooled (to around 45°C), and specially
prepared bacteria called ‘starter’ cultures are added. The milk is
kept at this temperature for approximately 4 to 7 hours to allow it
to ferment. Fermentation involves the harmless bacteria
converting the milk sugar (called lactose) into lactic acid.
 The increase in lactic acid decreases pH and causes the milk to
clot, or form the soft gel which helps to coagulate and set the milk,
producing curd.
Benefits of Curd:
 It is considered to as being a “healthy food” high in calcium which
is important for bone growth in children and for the prevention of
osteoporosis ( weak and brittle bones) in adults.

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Use of Bacteria in Making Cheese
 The major bacterias used for making cheese are as below :
 Lactobacillus delbrueckii
 subsp. bulgaricus
 Streptococcus thermophilus
Making of Cheese:
 The main ingredient in cheese is milk. Cheese is made using cow,
goat, sheep, water buffalo or a blend of these milks.
 Cultures for cheese making are called lactic acid bacteria (LAB)
because their primary source of energy is the lactose in milk and
their primary metabolic product is lactic acid. There is a wide
variety of bacterial cultures available that provide distinct flavor
and textural characteristics to cheeses.
 The type of coagulant used depends on the type of cheese
desired. For acid cheeses, an acid source such as acetic acid (the
acid in vinegar) or gluconodelta-lactone (a mild food acid) is used.
For rennet cheeses, calf rennet or, more commonly, a rennet
produced through microbial bioprocessing is used. Calcium
chloride is sometimes added to the cheese to improve the
coagulation properties of the milk

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Use of Bacteria in Curing Tea
Bacillus
Bacillus
 The major bacterias used for curing of tea are as below :
 Bacillus megaterium
 acidogenic bacteria
Curing of Tea (Process):
 Curing of tea leaves is brought about by the activity of Bacteria.
The bacteria which is used in curing tea is Bacillus megaterium.
Curing of tea leaves involves drying of leaves and losing green
colour.
 It is an oxidation dry fermentation reaction in which water is driven
off, the green colour is lost and the leaves assume a tougher
texture and undergo chemical changes.
 In the curing stage, Flavoured teas are manufactured by spraying
the tea with aromas and flavours or by storing them with their
flavorings.
 Tea becomes sweet and mellow through fermentation by age or
dampness. Amino acids and lipids break down completely, turning
the leaves blackish-brown in a fully oxidized tea
 Based on the degree and type of bacteria used for fermentation
and duration, different types of tea are formed.

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Use of Bacteria in Synthesis of Vitamin
 Probiotic bacteria, members of the gut microbiota, are able to
synthesize vitamin K and most of the water‐soluble B vitamins,
such as biotin, cobalamin, folates, nicotinic acid, panthotenic acid,
pyridoxine, riboflavin, and thiamine, in humans.
 Vitamin B12 synthesis by human small intestinal bacteria. In
humans, gut bacteria secrete vitamin B12 and a less familiar
micronutrient called vitamin K.
 Escherichia coli and closely related Salmonella typhimurium is
able to synthesize vitamin B12.
 Only a limited number of bacteria are known to produce vitamin
B12, three of which— Pseudomonas denitrificans , Bacillus
megaterium , and Propionibacterium freudenreichii.
 In the intestine of Herbivorous animals like cow and buffalo,
bacteria help in digestion of cellulose.
 Bacteria like Rumenococcus and ciliates like Entodinium
caudatum. These symbiotic microorganisms help in fermentation
and breakdown of cellulose and thus help in their digestion.
Escherichia coli
Escherichia coli

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Use of Bacteria in Agriculture
 Bacteria increase the fertility of the soil and provide such
nutrients to the soil which are useful for the plant growth. They
also help in softening the food in the seed and this is the reason
plants come out of the seeds.
 Bacteria perform many important ecosystem services in the soil
including improved soil structure and soil aggregation,
recycling of soil nutrients, and water recycling.
 Rhizobium is a bacteria that lives in a symbiotic relationship
between root nodules of leguminous plants. They fix the
atmospheric nitrogen and convert it into soluble nitrates, nitrites
and ammonium compounds. Nitrogen fixation helps in increasing
soil productivity and soil fertility.
 Similarly other bacteria like “Nitrosomonas”, “Nitrobacter” etc
also enrich the soil with nitrogen. The main functions of these
bacteria are as :
a. to supply nutrients to crops;
b. to stimulate plant growth, e.g., through the production of plant
hormones.
c. to control or inhibit the activity of plant pathogens.
d. to improve soil structure.
e. bioaccumulation or microbial leaching of inorganics.

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Thank You
Bibliography :
1) https://www.biotecharticles.com/Others-Article/Applications-of-Bacteria-in-Agriculture-
Environment-and-Dairy-Industry-
2) https://en.wikipedia.org/wiki/Yogurt
3) https://www.quora.com/What-is-the-bacteria-in-curd
4) https://sciencing.com/role-microbes-yogurt-production-8460533.html
5) https://www.cheesescience.org/microbes.html
6) http://milkfacts.info/Milk%20Processing/Cheese%20Production.htm
7) https://en.wikipedia.org/wiki/Cheese
8) https://www.vedantu.com/question-answer/curing-of-tea-leaves
9) http://www.envirobiotechjournals.com/article_abstract
10)https://edurev.in/question/99307/Name-the-bacteria-used-to-improve-the-flavour-of-Tea
Acknowledgement:
I wish to express my deep gratitude and sincere thanks to the Principal, Mrs Sudha Menon,
North Point School for her encouragement and facilities that she provided for this project work.
I extend my hearty thanks to Mrs.Swatilekha Bhattacharya Biology teacher, who guided me to
the successful completion of this project. I take this opportunity to express my deep sense of
gratitude for her invaluable guidance, constant encouragement, immense motivation, which
has sustained my efforts at all the stages of this Project work…
I can’t forget to offer my sincere thanks to parents and also to my sister who helped me to
carry out this project work successful and for their valuable advice and support, which I
received from them time to time….