A microorganism or microbe is “an organism which is microscopic making it too small to be seen by the unaided / naked human eye”. The study of microorganisms is called microbiology.
Main types of microorganisms
Main factors affecting to growth of microorganisms
Shapes of Bacteria
- Coccus:- Spherical or round shaped.
- Bacillus:- Rod shaped.
- Spiral:- Curve, spiral, or twisted shaped.
Structure of a bacteria
An example of, action of bacteria involved in food spoilage
- Lactic acid formation:- Lactobacillus, Leuconostoc
- Lipolysis:- Pseudomonas, Alcaligenes, Serratia, Micrococcus
- Pigment formation:- Flavobacterium, Serratia, Micrococcus
- Gas formation:- Lactobacillus, Leuconostoc, Proteus
Importance of bacteria (advantages)
Microbes are useful for us in many ways in various industries.
- Production of Foods
- Microbes are a key component in both home and industrial food preparation. Lactic acid bacteria are used to make yogurt, cheese, sour cream, buttermilk and other fermented milk products. Vinegar ,beer, wine, but bacteria are the agents of most other food fermentation’s. Other fermented foods include soy sauce, pickles, etc..
- Medical, Pharmaceutical and Biotechnological Applications (ex:-antibiotics and vaccines).
- Agricultural purposes.
- Oil eating bacteria (Alcanivorax)
Harmful effects of bacteria (disadvantages)
Though micro-organisms are very beneficial to living beings in a few ways, they can be lethal too. Micro-organisms (bacteria , fungi and viruses) cause various diseases in humans, plants and animals too.
- Food spoilage.
- Typhoid is caused by Salmonella typhi.
- Streptococcus pneumoniae and Haemophilus influenzae are responsible for the disease pneumonia in humans with infects the alveoli of the lungs.
- Common cold in humans is caused by a group of viruses called “Rhino viruses”.
Bacterial growth phase
- The bacterial growth curve represents the number of live cells in a bacterial population over a period of time.
- There are four distinct phases of the growth curve: lag, exponential (log), stationary, and death.
- The initial phase is the lag phase where bacteria are metabolically active but not dividing.
- The exponential or log phase is a time of exponential growth.
- In the stationary phase, growth reaches a plateau as the number of dying cells equals the number of dividing cells.
- The death phase is characterized by an exponential decrease in the number of living cells.
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05/05/2020 foodieson.com by @cheflakey