Food Microbiology Notes
Introduction to Food Microbiology
Food Microbiology:
The study of microorganisms associated with food.
The study of the role that microorganisms play in food spoilage, food production, food preservation, and food-borne disease.
Includes studying the microbial activities on food and their effects on consumers.
Microorganisms and Food
Foods carry microbial associations whose composition depends upon which organisms gain access and how they grow, survive, and interact in the food over time.
Microorganisms present will originate from:
The natural micro-flora of the raw material.
Organisms introduced in the course of harvesting/slaughter, processing, storage, and distribution.
Microbial presence will be determined by:
The properties of the food.
Its storage environment.
Properties of the organisms themselves.
The effects of processing.
Microorganisms manifest their presence in one of several ways:
They can cause spoilage.
They can cause foodborne illness.
They can transform a food’s properties in a beneficial way via food fermentation.
Food Spoilage
Occurs when the early stages of microbial processes in a food adversely affect its sensory properties (appearance, odor, or taste).
Stems from:
The growth of microorganisms in food.
The action of microbial enzymes.
Risk Factors:
New marketing trends.
Consumers’ desire for foods that are not overly processed and preserved.
Extended shelf life.
Chances of temperature abuse between production and consumption of foods.
New concepts are being studied to reduce contamination as well as control the growth of spoilage microbes in foods.
Not all food spoilage is necessarily microbial in origin.
Microbiological spoilage is paramount in more perishable foods such as meat, fish, and dairy products.
Foodborne Diseases
Many pathogenic microorganisms (bacteria, molds, and viruses) can contaminate foods during various stages of their handling, between production and consumption.
Consumption of these foods can cause foodborne diseases, which can be fatal and may also cause large economic losses.
Foods of animal origin are associated more with food borne diseases than foods of plant origin.
Risk Factors:
Mass production of food.
Introduction of new technologies in the processing and storage of food.
Changes in food consumption patterns.
Increased import of food from other countries, which has increased the chances of large outbreaks, as well as the introduction of new pathogens.
Fermentation
Microbes can play a positive role in food.
The activity of microorganisms frequently contributes to improved keeping quality in the product by inhibiting the normal spoilage flora.
Microbes can be consumed as foods in themselves, as in the edible fungi, mycoprotein, and algae.
Microbes can also effect desirable transformations in a food, changing its properties in a way that is beneficial.
Importance of Microorganisms in Food
Used as a food source/supplement.
Agents of fermentation.
Fermentation: any desirable change that a microorganism imparts to food.
Fermented foods: foods that have been intentionally altered by carefully controlling the activity of bacteria, yeasts, or molds.
Cause food spoilage.
Food spoilage: any change in the food that makes it unacceptable to the consumer.
Cause food poisoning or food-borne infection.
Contaminants
The number/kind of microorganisms present in food reflect the quality/safety of that food.