This document discusses biopreservation, which uses natural or controlled microorganisms and their antimicrobial compounds to extend the shelf life and improve the safety of foods. It describes various biopreservative agents like lactic acid bacteria, yeast, and bacteriophages and their modes of action in inhibiting pathogens. Specifically, it outlines classes of bacteriocins produced by lactic acid bacteria and their applications in preserving foods like meat, seafood, vegetables, and dairy products. The document also discusses regulatory requirements for using bacteriocins and the safety of lactic acid bacteria as biopreservatives.

1. BIOPRESERVATION
AVNEET KAUR
FSQM
317006

2. INTRODUCTION
 Contamination and spoilage by pathogens is a great
concern.
 Many chemical preservatives and physical treatments are
being used but they have many drawbacks.
 Therefore, biopreservation is a desirable alternative.

3. BIOPRESERVATION
 Extension of shelf life and food safety by the use of
natural or controlled micro biota and/or their antimicrobial
compounds.
 Beneficial bacteria or the fermentation products used in
biopreservation.
 Various modes of action are: organic acid production, a
wide variety of small inhibitory molecules including
hydrogen peroxide, etc.

4. BIOPRESERVATIVE AGENTS
Lactic acid
bacteria:
• Have
antagonistic
properties.
• Compete for
nutrients, their
metabolites,
hydrogen
peroxide, and
peptide
bacteriocins.
Yeast:
• competition for
nutrients,
production and
tolerance of
high
concentrations
of ethanol.
• synthesis of a
large class of
antimicrobial
compounds.
Bacteriophages
• viruses which
infect bacteria.
• Controls certain
bacterial
pathogens.

5. LACTIC ACID BACTERIA
 Include the genera Lactococcus, Streptococcus,
Lactobacillus, Pediococcus, Leuconostoc, Enterococcus,
etc.
 Preservation of the nutritional qualities of the raw material
through extended shelf life and the inhibition of spoilage
and pathogenic bacteria.

6. LAB BACTERIOCINS
Class I:
• Comprises the lantibiotics.
• Small peptides differentiated from others by their
content in dehydro amino acids and thioether
amino acids. E.g nisin
Class II:
• Comprises thermostable non-lantibiotic linear
peptides.
• Divided into three subclasses : the pediocin-like
bacteriocins (class II.1), the lack of leader peptide
(class II.2), or neither of the above traits (class
II.3).

7. Class III:
• Large heat-labile bacteriocins that
encompass many bacteriolytic extracellular
enzymes that may mimic the physiological
activities of bacteriocins.
• Examples :helveticin J of L. helveticus.
Class IV:
• New class created to include circular
antibacterial peptide.
• Distinguishing characteristic: existence of
head-to-tail peptide chain ligation.

8. REQUIREMENTS AND REGULATORY STATUS FOR
BACTERIOCINS
 GRAS status.
 Should have a broad spectrum.
 Thermostability.
 Beneficial effects and improved safety.
 No adverse effect on quality and flavour.

9. APPLICATIONS OF BACTERIOCIN-PRODUCING
LAB IN FOOD
 Inoculation of food with LAB where bacteriocins are
produced in situ.
 Use of food previously fermented with the
bacteriocin-producing strains as an ingredient in the
food processing (NisaplinTM, MicrogardTM, AltaTM
2341).
 Addition of purified or semipurified bacteriocins.

10. BACILLUS AS BIOPRESERVATIVE
Subtilin from B.
subtilis
Megacin from B.
megaterium
Thermacin from B.
stearothermophilus.

11.  Antimicrobial action against Gram positive and Gram
negative bacteria, as well as fungi.
 Safe for humans and would be no more of a risk than
lactic acid bacteria.
 The physiology/genetics of Bacillus are well understood.
 Inhibitory activity at alkaline, acidic condition or after
thermal processing and would be suitable for food
processing.

12. MEAT BIOPRESERVATION
 Extensively studied in fermented meat products and ready
to eat meat products.
 Competitive enhancement strategies include:
 A natural 'green' method
competitive
exclusion
prebiotic
probiotic

13. SEAFOOD BIOPRESERVATION
 Adding antimicrobials or by increasing the acidity of the
fish muscle.
 Less documented studies.
 Selection of potential protective bacteria in seafood
products is challenging.
 LAB remains the category that offers the highest
potential.

14. APPLICATIONS IN VEGETABLE PRODUCTS
 Nisin in tinned vegetables and fruit juices.
 Pediocin in salad and fruit juice.
 Enterocin AS-48 against B. cereus in rice and vegetables.
 In fruit juices against other pathogens such as E. coli
O157:H7, S. aureus, and the spoilage bacterium
Alicyclobacillus acidoterrestris

15. APPLICATION OF BACTERIOCINS IN DAIRY PRODUCTS
Nisin and/or nisin-producing
strains against Clostridium
butulinum in cheese and
against L. monocytogenes in
cheeses such as Camembert
, Ricotta , and Manchego .
Pediocin AcH in milk and
Cheddar and Munster
cheeses against L.
monocytogenes, S. aureus,
and E. coli O157:H7.
Lacticin 3147 against
undesirable LAB, L.
monocytogenes and B.
cereus in Cheddar, Cottage
cheese and yogurt .
Enterocin AS-48 against B.
cereus, S. aureus and L.
monocytogenes in milk.

16. BACTERIOPHAGES
 This specificity has allowed for directed targeting
and killing of pathogenic bacteria using phages in
what is referred to as phage therapy.

17. MODE OF ACTION

19. SAFETY
 LAB and their bacteriocins have been consumed
unintentionally for ages, laying down a long history of safe
use.
 Factors: antimicrobial spectrum of inhibition, bactericidal
mode of action, relative tolerance to processing conditions
and the lack of toxicity.
 The evaluation done in meat by USDA.

20. THANK YOU!