ROLE OF MICROORGANISMS IN FOODS
Since 1900 A.D. our understanding of the importance of microorganisms in food has increased greatly. Their role in food can be either desirable (food bioprocessing) or undesirable (food borne diseases and food spoilage), which is briefly discussed here.
1. Food-borne 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 food borne diseases. Food borne diseases 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.
Mass production of food, introduction of new technologies in the processing and storage of food, changes in food consumption patterns and increased import of food from other countries have increased the chances of large outbreaks as well as the introduction of new pathogens.
Effective intervention technologies are being developed and implemented to ensure the safety of consumers against food borne diseases. New methods are also being developed to effectively and rapidly identify the pathogens in contaminated foods.
2. Food Spoilage
Except for sterile foods, all foods harbor micro-organisms. Food spoilage stems from the growth of these micro-organisms in food or is due to the action of microbial enzymes.
New marketing trends, consumers’ desire for foods that are not overly processed and preserved, extended shelf life, and chances of temperature abuse between production and consumption of foods have greatly increased the chances of food spoilage and, in some instances, with new types of micro-organisms.
The major concerns are the economic loss and wastage of food. New concepts are being studied to reduce contamination as well as control the growth of spoilage microbes in foods.
3. Food Bioprocessing
Many food-grade micro-organisms are used to produce different types of fermented foods using raw materials from animal and plant sources. Consumption of these foods has increased greatly over the last 15 to 20 years and is expected to increase further in the future. There have been great changes in the production and availability of these microorganisms (starter cultures) to meet the large demand. In addition, novel and better strains are being developed by using genetic engineering techniques.
4. Food Additives
Microbial enzymes are also being used to produce food and food additives. By employing genetic recombination techniques, and using diverse microbial sources enzymes of higher purity & activity are obtained. Many types of additives from microbial sources are being developed and used in food. Some of these include single-cell proteins, essential amino acids, color compounds, flavor compounds, stabilizers and organic acids.
5. Food Biopreservation
Antimicrobial metabolites (e.g. bacteriocins and organic acids like acetic, propionic and lactic acids) of desirable Micro-organisms are being developed and used in foods in place of preservatives of non-food (chemical) origin to control pathogenic and spoilage microorganisms in food. Economic production of these antimicrobial compounds and their effectiveness in food systems have generated wide interest.
Consumption of foods containing live cells of bacteria and that have apparent health benefits has generated interest among consumers. The role of these bacteria for health and bacterial efficacy benefits is being critically investigated.