PRACTICAL 1 INTRODUCTION TO THE FACILITIES AND MEDIUM USE IN MICROBIOLOGICAL ANALYSIS
Introduction
Microbiology is defined as the scientific study of microorganisms. Microorganisms or also known as microbes are minute living things that individually are usually too small to be seen with the unaided eye. There are 9 Safe Practices for the Microbiology Laboratory (James, 2008) that should follow when working with microorganisms. The first safe practice is to treat all microorganisms as potential pathogens. Secondly, sterilize all equipment and materials by using autoclave. The third safe practice is disinfecting work areas before and after use. Another safety practices are wash hands, never pipette by using mouth, do not eat or drink in the laboratory, not to store food in areas where microorganisms are stored, always label everything clearly, autoclave or disinfect all waste material and lastly clean up spills with care.
OBJECTIVE
1. To study good and safe microbiology laboratory rules, instruments and its procedures on how to use it.
RESULTS
No. Media/Instruments Descriptions
1. General chemicals
Microbiological media: agar/ broth/ chemical
Microbiological media are liquids or gels which act as perfect medium for the growth of microorganisms. Media varies for growing different types of cells. For instant, nutrient media contain all the elements that are needed for growth of some bacteria. The most common growth media used are nutrient broth and agar.
2. Micropipette
The functions of Micropipettes are it is used to measure and deliver accurate volumes of liquid in a much smaller volume, starting at 1 microliter.
3 Petri Dish
Petri dish also known as Petri plate or cell-culture dish is a shallow cylindrical glass or plastic lidded dish that function to culture cells. For example, bacteria.
4 Inoculation loop
Inoculation loop, also known as a smear loop, inoculation wand or micro-streaker, function to as a tool to retrieve an inoculum from a culture of microorganisms. Inoculation loop is used in the cultivation of microbes on plates by transferring inoculum for streaking.
5 L-shape rods
L- shape rods function to spread bacterial cultures evenly which allows application on the entire petri dish.
6 Autoclave
Autoclaves mainly function to sterilize liquid substances such as prepared media and saline (diluents) solutions. It is also function to sterilize glassware’s, when required
.
7 Laminar air flow
Laminar air flow function as a chamber for aseptic transfer of sterilized materials and inoculation of microbes.
8 Incubator
Incubator function to allow growth of microbes by growing them at suitable temperatures. First, Inoculate the desired microbe into a suitable culture medium. Secondly, incubate it at the temperature optimum for its growth.
This process called incubation where usually temperature for incubation is 37°C.
9 Centrifuge
Centrifuge function to separate the components of material according to their specific gravity by spinning a material at a high speed. Also, It is used to apply specific forces onto the material and separate items in suspension. There are three main components of centrifuge which consists of a electric motor, a shaft attached to the motor, and a hub with places for the material containers to be spun. The larger the centrifuge, the more number of materials can be spun with it.
10 Sterilizing oven
Sterilizing oven function to glassware sterilization such as test tubes, pipettes and petri dishes.
11 Water purification system
Water purification system function to remove undesirable chemicals, biological contaminants, suspended solids and gases from contaminated water. The aim of water purification system is to produce water fit for a specific purpose. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light.
By purifying water, it reduce the concentration of particulate matter including suspended particles, parasites, bacteria, algae, viruses, fungi, as well as reducing the amount of a range of dissolved and particulate material derived from the surfaces that come from runoff due to rain.
12 stomacher
Stomacher also known as homogenizer, the Stomacher function to homogenized various food samples. In microbiology lab, stomacher released significantly larger numbers of viable micro-organisms, calculated on the basis of a colony count, than other methods of homogenization, except from samples of cheese and powdered egg and milk. A advantage of using the Stomacher is that no sterilization or maintenance needed.
13 freeze dryer
Freeze dryer use in dehydration technique. A dehydration technique enables liquid which have previously been frozen to be dried under a vacuum.
Freeze-drying also known as lyophilisation is an effective way of drying materials without harming them. It makes use of the physical phenomenon of sublimation, which involves the direct transition between the solid state and the gaseous state without passing through the liquid phase. To achieve this, the frozen product is dried under vacuum, without being allowed to thaw out.
14 water bath
Water bath function to maintain water at a constant temperature. In microbiology lab, water bath used for incubations purposes.
At the first period of lab period, water bath should be check to see if it is turned on, set at the right temperature, and filled with water. It should be filled with distilled water. Water bath temperature should be check frequently to make sure that the water bath is maintaining the proper temperature.
15 Spectrophotometer
Spectrophotometer functions for measuring the differences in color intensities of solutions. A beam of light of a particular wavelength is passed through the test solution and the amount of light absorbed (or transmitted) is measured electronically.
A simple visible spectrophotometer can pass light with wavelengths within visible range, whereas a UV-visible spectrophotometer can pass light with wavelengths in ultraviolet as well as in visible range. In microbiology lab, it is used for direct counting of bacteria in suspension as well as for other purposes.
16 Colony counter
Colony counter function for enumeration of bacteria in samples, it is assumed that a single bacterium gives rise to a single visible colony, when grown on a plate of solidified nutrient medium. By using colony counter to count the number of colonies, the number of bacteria in a sample can be estimated. Moreover, colony counter make it easier to count colonies which very small and too much crowded. It divides the plate into several square divisions and the colonies are magnified 1.5 times by a magnifying glass, which makes counting easy.
17 Water dispencer
Water dispenser also known as water cooler function to cools and dispenses water.
18 Media preparatory
Automated media preparatory function to prepare, sterilize and dispense liquid or solid culture media automatically.
Advantages of media preparatory are reduces labor costs, high consistency and uniform volumes independent of operator. Moreover, processing can be monitored fully which allows easier conformance to GLP, storage space and facilities costs reduced, more safe for laboratory personnel (no hot agar/broths to carry around) and 'out of stock' situations reduced compared to ready to use media.
19 Biolog identification system
Biolog also known as Microbial Identification Systems. Biolog function for testing and identification of aerobic Gram-negative and Gram-positive bacteria in the same test panel. By using biology identification system there is no need to conduct Gram stain and other pre-tests. Using biolog it is a simple, one minute setup protocol is used for each sample.
Conclusion
In conclusion, working in laboratory important to be careful and practices safe work practices. In microbiological laboratory, every type of equipment have their own function and before using it the procedure of equipment should be understand and practices well to prevent unwanted situation.
References
1) Tortora, G.J., Funke, B.R & Case, C.L. 2010. Microbiology: An Introduction. ¬¬¬¬¬¬¬¬¬¬¬¬¬¬10th edition. Person Education Inc.
2) James, Daniel E., 2008. Nine Safe Practices for the Microbiology Laboratory Carolina Biological Supply, Burlington, NC.