Part 1 of biopreservatives

1. FOOD
BIOPRESERVATIVES
PRESENTATION II
MUNNA IYPE JOY
315009
M-TECH FSQM

2. Topics Covered
1.Food Preservation
2.Need for preservation
3.Biopreservation and its relevance
4.Methods of preservation
A)Physical methods of preservation( Heat and Energy)
i)Hight temperature
ii)Low temperature
iii)Special Treatments

3. • B)Chemical & Biological methods of preservation
• i)Addition of chemical preservatives
• ii)Action of microbes
a)Bioprotective Cultures
b)Fermentates
iii)Antimicrobial agents of natural origin
a)Direct antimicrobial preservatives
b)Indirect antimicrobial preservatives

4. iv)Antioxidants
v)Bacteriophages
5.Future research
6.Case Studies

5. Todays agenda…
Preservation
using
microbes
Bioprotective
cultures
Fermentates
Bacteriophages

6. A. BIOPROTECTIVE CULTURES
• Food fermentations – oldest
preservations known to man.
• Better keeping qualities and
organoleptically pleasing
characteristics.
• Most explored fermentation area –
Dairy fermentation
• Majority of fermentations are
dependent on lactic acid
bacteria(LAB)
• Preservative effect due to the

7. Common Fermented foods
Sl
No
.
Food
product
Substrate Microorganism
1 Bread Wheat Saccharomyces cerevisiae , lactic acid
bacteria
2 Buttermilk Milk Lactic acid bacteria
3 Yoghurt Milk, milk solids S . thermophilus ,
Lb . bulgaricus
4 Sauerkraut Cabbage Lactic acid bacteria
Ln . mesenteroides ,
Lb . brevis ,Lb . plantarum ,
Lb . curvatus , Lb . Sake
5 Pickles Cucumber P . cerevisiae ,
Lb . plantarum

8. Common Fermented foods
contd…
Sl
No
Food
product
Substrate Microorganism
6 Cheese Milk Lactic acid bacteria,
(L . lactis , S . thermophilus ,
Lb.shermanii)
Propionibacterium
shermanii
7 Idli Rice and black gram
dhal
Lactic bacteria
(Ln . mesenteroides , E . faecalis)
Torulopsis , Candida ,
Trichosporon pullulans
8 Wine Grapes Yeast & LAB
9 Beer Barley Yeast

9. Benefits of Fermented foods
1. Safety
2. Health benefits
3. Retail value
4. Nutritional value
5. Digestibility
6. Suitability for
subsequent
processing
7. Sensory
properties
8. Ease of storage
and
transportation
9. Shelf life
1. Toxicity
2. Cooking time
3. Production costs
4. Equipment
needs
5. Levels of
antinutritional
factors

10. Mechanisms of antibiosis
(Purview of LAB)
I. Organic Acids
II. Hydrogen Peroxide
III. Carbon Dioxide
IV. Diacetyl
V. Broad-spectrum Antimicrobials -
Reuterin
VI.Bacteriocins

11. (I) Organic Acids
• Lactic acids, Acetic acids,
Propionic acids
• Acids acts on the cytoplasmic
membrane- active transport is
inhibited or destroyed
• Action is observed in both
undissociated and dissociated
form

12. (II) Hydrogen Peroxide
• Lactic acid bacteria lack true
catalase to break
down the hydrogen peroxide
generated.
• Inhibition is mediated through the
strong oxidising effect on membrane
lipids and cell proteins.
• Hydrogen peroxide may also activate
the lactoperoxidase system of fresh

13. (III) Carbon Dioxide
• Formed from heterolactic
fermentation
• Create an anaerobic environment
toxic to some aerobic food
microorganisms
• Action on cell membranes and its
ability to reduce internal and external
pH
• Production of eyes in Swiss cheese.

14. (IV) Diacetyl
• Product of citrate metabolism.
• Responsible for the aroma and
flavour of butter
• Gram-negative bacteria, yeasts and
moulds are more sensitive to diacetyl
• mode of action is interference with
the utilization of arginine

15. (V) Broad-spectrum
Antimicrobials - Reuterin
• Produced during stationary phase by
the anaerobic growth of Lactobacillus
reuteri
• Has a general antimicrobial spectrum
affecting viruses, fungi and protozoa
as well as bacteria
• Its activity is thought to be due to
inhibition of ribonucleotide reductase

16. Acetic acid Bacteria
•Acetic acid is one of the oldest
chemicals known
Acetic
acid
bacteria
Acetic
acid
bacteria
Acid
tolerant
Below
pH 5.0
Obligate
aerobes
Gram-
negative

17. •They derive energy from the
oxidation of ethanol to acetic acid
C 2 H 5 OH + O 2  CH 3 COOH + H 2 O
• In liquids, they grow as a surface
film because of their demand for
oxygen.
•Produces vinegar and under
Aerobic condition wine.
Acetic acid Bacteria

18. Yeasts
•Yeasts are rarely toxic or pathogenic
•Yeasts have been classified into
about 500 species
•Saccharomyces cerevisiae is the
most frequently used

19. Essentials of Bio protective
Cultures
• Strains used should not be cross
resistant
• Starters and their derivatives should
be recognized as GRAS
• Otherwise need premarketing
approval(EU)
• No regulation in FSSAI
• FDA has published draft

20. B. FERMENTATES
• Fermentates are fermented food
ingredients
• Variety of raw materials - typically
milk, sugar, or plant-derived material
• The fermentation is designed to
provide a high yield of antimicrobial
metabolites
• Complex products that inherently do
not have a well-defined composition
• Usually supplied as a dry, cell-free

21. • commercially available fermentates
for use in foods are the MicroGARD
range (DuPont), DuraFresh
range (Kerry)
• Spray-dried vinegar, fermented
wheat flour products - only limited
scientific reports available on the
functionality of fermentates in foods.
B. FERMENTATES contd…

24. • Casein Fermentate of Probiotic
Lactobacillus Spp. has shown good
antimicrobial property.
Antimicrobial Activity of Whey fermentate of
selected Lactobacillus cultures against S.aureus
Zone of inhibition - 14-25mm dia

25. C. BACTERIOPHAGES
• Phages that attack bacteria
• They are harmless to humans,
animals, and plants
• Phages are renowned in the dairy
industry for attacking starter cultures
during fermentation
• Drug-resistant bacteria have become
a global
problem
• Phages are specific and efficient in host

26. Applications Include
I.Prevent or reduce colonization and
diseases in livestock (phage
therapy)
II.Decontaminate carcasses and other
raw products, such as fresh fruit and
vegetables, and to disinfect
equipment and contact surfaces
(phage biosanitation)
III.Extend the shelf life of perishable
manufactured foods as natural

27. Considerations
Phages will typically become
inactivated or bound in the
food matrix.
Their target organism is not able to
prevent regrowth of surviving cells
Application method must ensure
that the phages are well distributed
in the product
Using them with other hurdles that
provide growth inhibition or in

28. Lytic cycle of Phage

29. Endolysins
• Phages either release new ones
without killing the cells or break the
peptidoglycan to release new ones.
• Endolysins are produced during late
phase of gene expression
• Responsible for enzymatic cleavage
of peptidoglycan
• Peptidoglycan damage leads to lysis
of the cells
• In regard to food preservation ,
research is still at infancy

30. Thank You...