food microbiology

1. INTRODUCTION TO
FOOD MICROBIOLOGY
MICRO-509

2. FOOD MICROBIOLOGY
• The study of microorganisms that inhabit, create or contaminate food including
the study of microorganisms causing food spoilage.

3. GOALS
• To use microorganisms to enhance or produce new food products ( e.g
fermentation, cheese and wine making)
• To study disease/spoilage causing microorganisms and their prevention.

4. FOOD
• Any substance consumed to provide nutritional support for the body
• Food supply basically consist of plants and animal origin or products derived
from them
• It is understandable that our food supply can contain microorganisms in
interaction with food.
• These microbes use food as a source of nutrients for their own growth.

5. CON..
• This will cause two possibilities:
• Either result in deterioration of food (spoilage)
• OR these interaction between microbes and food can give benefits to humans.

6. EXAMPLE
• Two species of Penicillium fungus are named after cheeses.
• One of them is P. roqueforti, gives blue cheese.
• Cheesemakers add P. roqueforti to the milk, so its present throughout the cheese.
• The blue mold grows and produce the beautiful blue veins that characterize these
cheese.

7. HOW MICROBES CAN CAUSE DETERIORATION OF
FOOD?
• When they utilize nutrients of food it involve changes in the food compound like:
• Synthesis of a new compound that cause spoiling of food OR
• Produce enzymatic changes and contributing off-flavors by mean of breakdown
of product.

8. WHAT IS THE IMPORTANCE OF MICRORGANISMS IN
FOOD?
Good (Desirable) Bad (Undesirable)
Food bioprocessing Foodborne dissease
Food biopreservation Food spoilage
Probiotics

9. GOOD (DESIRABLE)
1. FOOD BIOPROCESSING
• Means food produce by biological processes.
• In this process, food grade microbes are used to produce different types of
fermented food using raw materials from animals or plant sources (this process
known as starter culture)
• Besides, microbial enzymes are also being used to produce food and food
additives.

10. STARTER CULTURE
• A concentrated preparation of live cells that is added to raw material to initiate
fermentation rapidly.

11. 2. FOOD BIOPRESERVATION
• In this process food is preserved by using antimicrobial metabolites (taken from
certain microbes in order to control pathogenic and spoilage microbes in food).
• In biopreservation, beneficial bacteria are used to prevent food spoilage and get
rid of harmful pathogens.
• Lactic acid bacteria (LAB) are most commonly used due to their unique properties
and because they are harmless to human.
• LABs release antimicrobials (such as lactic acid, acetic acid, hydrogen peroxide
and peptide bacteriocin) that stop spoilage and inhibit the growth of harmful
pathogens.

12. PROBIOTICS
• It’s a concentrated supplement of beneficial live cells of bacteria (friendly
bacteria) culture taken orally, intended to improve our health by promoting our
body’s natural immunity and improving digestion system.

13. EXAMPLE OF PROBIOTICS IN FOOD
• Baby milk nowadays is supplemented with Lactobacillus acidophillus and Bifidius
bacteria.
• Yougurt-rich with live bacteria culture such as Lactobacillus bulgaricus and
Streptococcus thermophilus.
• Cheese friendly bacteria that is added in cheese is Lactobacillus.