microbiology applications in food

1. Submitted by:
Aditi Singh
B.Tech (BT) V Sem.
Roll no.- 7274
Submitted to:
Dr.Monika Saxena
Deptt. Of Bioscience
& Biotechnology

2. Industrial applications of
microbiology
In food

3.  Organism
 With ability to grow rapidly
 Non-pathogenic
 Medium
 Available in abundant quantities
 Must be cheap
 Product
 Efficient + Economical recovery methods
 purification

4. Microorganisms used:
 Several strains of algae, fungi (yeast & molds),
bacteria, protozoa, and viruses.
 Genetic Engineering of microorganisms:
Genetic engineering, also known as recombinant
DNA technology, molecular cloning or gene
cloning
Recombinant DNA Technology enables
isolation of genes from an organism, this
gene can be amplified, studied, altered &
put into another organism

5.  Recombinant DNA
procedure:
1. Cutting of donor DNA :
Restriction endonucleases cut DNA
molecule at specific sites and desired
fragment is isolated by gel
electrophoresis.
2. Cloning of a gene:
DNA fragment, which wanted to be
cloned, is joined to one of vectors
(plasmid, phage, cosmid). For this
purpose, vector and donor DNA are
first cleaved with the same restriction
endonuclease, or with the ones
producing the same ends.

6. Then using DNA ligase, DNA
fragment and vector DNA is joined. If
fragment has no sticky ends,
homopolymer tailing or linker DNA
segments can be applied for this step.
3. Transformation :
Recombinant vector is put into
suitable host organism, like;
bacteria, yeast, plant or animal cells,
by several physical or chemical
methods. Transformed cells are
identified by several ways:
a. Insertional inactivation (of
antibiotic resistant genes on
plasmids),
b. nucleic acid hybridization
c. labeled Ab's for specific
proteins (immunological test)
are helpful for screening
recombinant colonies.

7.  Factors affecting microbial growth in food
 composition
 pH
 presence and availability of water
 oxidation-reduction potential
 altered by cooking
 physical structure
 presence of antimicrobial substances
 temperature
 lower temperatures retard microbial growth
 relative humidity
 higher levels promote microbial growth
 atmosphere
 oxygen promotes growth
 modified atmosphere packaging (MAP)
 use of shrink wrap and vacuum technologies to package food
in controlled atmospheres

8. Fermented
food
products
Citric
acids
Amino
acids
Enzymes
Industrial
Production
In field of foods
Vitamins
others

9. 1. L-lysine Production:
• Essential amino acids –for human nutrition.
• Used as supplement for bread , cereals & other food.
• Two steps for commercial production method:
I. Formation of DAP(diaminopimedic acid) by E.coli .
II. Decarboxylation of DAP by DAP decarboxylase
enzyme from Enterobacter aerogenes .
DAP Lysine + CO2
 E.coli – grown in a medium consisting glycerol of corn steep
liquor and (NH4)2HPO4 - under controlled conditions of aeration,
temperature & pH for optimum DAP production.
 After several days, Enterobacter aerogenes - added to the mixture -
produces an enzyme DAP decarboxylase that removes the
carboxyl group from DAP to produce lysine

10. 2. L-Glutamic Acid Production:
• Produced by certain species of Micrococcus, Arthrobacter and
Brevibacterium .
• Medium consists of carbohydrates , peptone, inorganic salts & biotin.
• Precursor : -ketoglutaric acid ; enzyme: glutamic dehydrogenase.
• Used in food supplement for human and animals, and its sodium
salt (monosodium glutamate) is utilized in food preparation.
• Used as condiment & flavor-enhancing agent
in form of monosodium glutamate.
Brevibacterium

11.  This organic compound used in flavoring extracts in soft drinks, foods
& candies; in inks,dyeing, pharmaceuticals (like anticoagulant).
 Organism most widely used is the mold: Aspergillus niger
 Substrate: Molasses
 Sterile medium in dispensed into shallow pans – inoculated with
mold pores – under aerobic conditions
 Submerged-culture technique: inoculated medium contained in large
tanks through wide supply of air is forced; following affects the yield
of citric acid:
 Strain of mold employed
 Composition of medium
 Degree of aeration
 Temperature of incubation

12. • Food supplements
• Microbes can provide inexpensive source of vitames
i) Riboflavin (vitamin B2)
 Produced by Ashbya gossypii(fungi) by fermentation, a mold that
produces 20,000 times the amount it needs for its metabolism.
Ashbya gossypii

13. ii) Cyanocobalamin (Vitamin B12)
• Produced by Pseudomonas, Propionibacterium, Streptomyces grown
in a cobalt-supplement medium.
• This vitamin used in bread, flour, cereal products and animal
feeds
Propionibacterium
iii) Ascorbic Acid (Vitamin C )
• Produced at the rate of 20,000 tonnes per year
• by a complicated modification of glucose by Acetobacter sp.

14. i) Amylase
 produced by the mold of Aspergillus oryzae
 Used as a spot remover in laundry presoaks, as an adhesive in
baking.
Aspergillus oryzae Clostridium spp
ii) Pectinase
 produced by Clostridium sp.
 used to ret flex for linen and also used in fruit juice.

15. iii) Proteases
 group of protein digesting enzyme produced by Bacillus subtilis,
Aspergillus oryzae
 Certain proteases are used in leather manufacturing, liquid glues,
laundry presoaks, meat tenderizers, drain openers and spot
removers.
Yeast
iv) Invertase
 produced by yeasts
 use in making soft centered chocolate
Bacillus subtilis

16. v)Rennin
 Produced commercially by fungi; but more recently by genetically
modified bacteria
 Used to form curds in milk
vi) Alginates
 Is a typical of the miscellaneous microbial products.
 Is a sticky substrate used as a thickener in ice cream, soups or
other food.

17.  Industrial fermentation –
Large scale cultivation of microbes/single cells – to
produce desired products
Used in anaerobic food fermentations:
o Vinegar production
o Lactic acidproduction
o Brewing & wine making industries
o Dairy products
In biotechnology to obtain useful products from GM
plants & animals
Vessels called as BIOREACTORS – to control:
 Aeration
 pH control
 temperature

18. • Derived from French word
vinagre, meaning sour wine.
• Steps of production:
1. An alcoholic fermentation of
carbohydrate – yeast
fermentation
2. Oxidation of alcohol to acetic
acid – the acetic acid bacteria ,
species of genus Acetobacter
(inoculated onto the shavings)
• Medium : milk used in “building-up”
the inoculum

19. • Vinegar, apple vinegar,
cider vinegar

20. Lactic acid
• A compound employed to preserve foods,
finish fabrics
• Lactic acid is commonly produced by bacterial
activity on the whey portion of milk.
• Microorganism involved in this organic
compound: Lactobulgaricus

21. Beer

23.  involves growth of
Saccharomyces cerevisiae
(baker’s yeast) under
aerobic conditions
 maximizes CO2
production, which
leavens bread
 other microbes used to
make special breads
(e.g., sourdough
bread)
 can be spoiled by
Bacillus species that
produce ropiness

24. Yogurt
 Milk is feremented by a mixture of Streptococcus salivarius ssp
thermophilus and Lactobacillus bulgaricus Often these two are
co-cultured with other lactic acid bacteria for taste or health
effects (probiotics). These include L. acidophilus, L. casei and
Bifidobacterium species.
 Acid produced from the fermentation causes the protein in
the milk (casein) to coagulate into a semisolid curd

25. Cheese
 Milk is treated with lactic acid bacteria and an
enzyme called rennin that partially hydrolyses the
protein and causes it to coagulate into “curds.”
The liquid portion of the milk at this time is called
“whey.”
 The whey is separated from the curds, and the
curds are aged (“ripened”)
 Different microbes in the early and late stages of
processing give rise to cheeses with different
characteristics

26. Other fermented foods
 sausages
 hams
 bologna
 salami
 izushi – fish, rice, and vegetables
 katsuobushi – tuna
 sauerkraut

27. for
Your
Attention...