This document discusses lactic acid bacteria (LAB) and their use as natural biopreservatives in food. LAB produce antimicrobial compounds that inhibit the growth of food spoilage bacteria and fungi. As starter cultures, LAB compete with and inhibit other microorganisms while converting sugars to lactic acid, lowering the pH and increasing the fermentation efficiency to preserve foods. Common LAB like those used in yogurt production are effective biopreservatives applied to various fermented foods.

1. Lactic acid bacteria as natural
biopreservative

2. Introduction
 Biopreservation is the use of natural microbiota or antimicrobial
for preserving food and extending its shelf life.
 Most common forms is fermentation
 Lactic Acid Bacteria (LAB), generally considered food-grade
organisms

3. Spoilage microorganisms
 Bacteria
 Fungus
 Mold
 Yeast
 Virus

4. Lactic acid bacteria LAB as biopreservatives
Antimicrobial compounds produced by LAB prevent
growth of food spoilage bacteria and fungi

5. How do LAB cultures work as a hurdle?
• Compete with the indigenous flora
• Inhibit the indigenous flora

6. LAB biopreservative methods
 LAB as functional starter cultures for the food
fermentation
 LAB antimicrobial compounds or inhibitory
metabolites used as biopreservatives

7.  Convert sugars to lactic acid
 Increase the lactic acid concentration to 0.8 to 1.2 %
 Drop the pH to between 4.3 to 4.5
 Increased fermentation efficiency
LAB as functional starter cultures for the
food fermentation

8. Applications of LAB starter cultures used as biopreservatives
in fermented food products

9. Types of LAB used as starter culture
Homofermentative
Producing >85% lactic acid
Heterofermentative
CO2+ Ethanol and Acetic acid in equimolar amount

10. LAB used in yoghurt
Starter culture

11. Commercially available products based on LAB
protective cultures

12. Antimicrobial compounds or secondary
metabolites produced by LAB

13. Isolation and identification
of antimicrobial
compounds from LAB

14. Application of LAB secondary metabolites in food
preservation
 Control of mycotoxin contamination.
 The inhibition of aflatoxin accumulation.
 Control of postharvest diseases in fruits & vegetables.

15. Treatment of fungus and LAB antimetabolites as
preservatives on soya been

16. Health benefits
 Probiotic cultures
-stabilizing or normalizing the gastrointestinal tract
-increase function of immune system
 Production of Vitamins & precursors
Vit-B 12 , Riboflavin, Vit-C precursor

17. Conclusion
 The research field of antimicrobial LAB is still very novel.
 The application of LAB have positive effect on food industry.
 LAB inhibits the growth of the pathogens by synthesizing the
antimicrobial compounds.