Paper No.: 03
Paper Title: FOOD MICROBIOLOGY
Module – 13: Biopreservation of foods CONTENTS
1. Introduction
2. Biological methods for food preservation
2.1 Lactic Acid Bacteria
2.1.1 Bacteriocins from Lactic Acid Bacteria
3. Application of bacteriocins in selected foods
4. Limitations of Biopreservation process BIOPRESERVATION
Biopreservation is the use of natural or controlled microbiota or antimicrobials as a way of preserving food and extending its shelf life.
Beneficial bacteria or the fermentation products produced by these bacteria are used in biopreservation to control spoilage and render pathogens inactive in food.
The main purpose of the use of such practices is to restrict the number of microorganisms present in the food. BIOLOGICAL METHODS FOR FOOD PRESERVATION
Biopreservation is practiced to extend the shelf life and food safety through the use of natural or controlled microbiota and or their antimicrobial compounds.
The easiest forms of food biopreservation are fermentation, a process based on the growth of microorganisms in foods, whether natural or added.
Conventionally, a several number of foods have been protected against spoiling by natural processes of fermentation.
Lactic acid bacteria (starter/protective cultures), which produce organic acids and other compounds that, in addition to antimicrobial properties, also confer unique flavours and textures to food products. …….BIOLOGICAL METHODS FOR FOOD PRESERVATION
Bacteriocins from Lactic Acid Bacteria
Bacteriocins are the antimicrobial ribosomally synthesized peptides produced by LAB and other bacteria.
Such peptides are effective to kill only closely related microorganisms and very sensitive in nature, they are inactivated by proteases in the GIT. http://en.wikipedia.org/wiki/Class_II The bacteriocins can effectively be used to inhibit some _bacteriocin gram-positive bacteria, spore-forming bacteria, and food- borne pathogens. APPLICATION OF BACTERIOCINS
Inoculation lactic acid bacteria in the food where bacteriocins are produced in situ. Here, the ability of the starter culture to grow and conditions to produce bacteriocins in the products is very critical for its successful application.
Addition intact bacteriocins, which may be purified or semi-purified as food preservatives. http://www.freewtc.com/products/pr
Use of a food product earlier fermented with a obiotic-toothpaste-593684- 40876.htm bacteriocins producing strain as an ingredient in food processing. LIMITATIONS OF BIOPRESERVATION PROCESS
The main functional limitations for the application of bacteriocins in food preservation:
Its relatively narrow inhibiting activity spectrum and usually active against only one target microorganism.
They are generally not active against gram-negative bacteria.
The activity of bacteriocin is not stable and loss occurs when it interacts with food components by binding with some other food components such as lipids and proteins or being degraded by proteolytic enzymes. THANK YOU