LAB 3 MOHAMMAD SYAFIQ BIN ABDULLAH 113569

INTRODUCTION

Culture media are available commercially as powders; they require only the addition of water. Nutrient medium is a general purpose preparation for  culturing microorganisms which are not nutritionally fastidious. The broth contains:

3.0 g/L “Lab-lemco” powder (beef extract)

2.0 g/L yeast extract

5.0 g/L peptone (nitrogen source)

5.0 g/L sodium chloride

2.0 g/L agar powder

The agar has the same composition, except that contains 15 g/L agar. The final pH of both media is 7.4

Autoclaves are widely used in microbiology, medicine, tattooing, body piercing, veterinary science, mycology, dentistry, chiropody and prosthetics fabrication. They vary in size and function depending on the media to be sterilized.

Typical loads include laboratory glassware, surgical instruments, medical waste, patient pair utensils, animal cage bedding, and lysogeny broth.

A notable growing application of autoclaves is the pre-disposal treatment and sterilization of waste material, such as pathogenic hospital waste. Machines in this category largely operate under the same principles as conventional autoclaves in that they are able to neutralize potentially infectious agents by utilizing pressurized steam and superheated water. A new generation of waste converters is capable of achieving the same effect without a pressure vessel to sterilize culture media, rubber material, gowns, dressing, gloves, etc. It is particularly useful for materials which cannot withstand the higher temperature of a hot air oven. For all-glass syringes, sterilizing in a hot air oven is a better method.

OBJECTIVE

To prepare sterile nutrient agar for culturing microorganisms.

DISCUSSION

a source of amino acids and nitrogen (e.g., beef, yeast extract).  This is an undefined medium because the amino acid source contains a variety of compounds with the exact composition being unknown. Nutrient media contain all the elements that most bacteria need for growth and are non-selective, so they are used for the general cultivation and maintenance of bacteria kept in laboratory culture collections.

Physcomitrella patens plants growing axenically on agar plates. An undefined medium (also known as a basal or complex medium) is a medium that contains a carbon source such as glucose for bacterial growth, water and various salts needed for bacterial growth. A defined medium (also known as chemically defined medium or synthetic medium) is a medium in which all the chemicals used are known no yeast, animal or plant tissue is present. A differential medium is a medium that includes some sort of added indicator that allows for the differentiation of particular chemical reactions occurring during growth.

They are different sterilization methods for medical instruments, consumables, devices and Implantable devices. Depending on the nature of the product to sterilize is the method used.
Sterilization can be achieved through application of heat, chemicals, irradiation, high Pressure or filtration.
Heat Sterilization is divided in two categories: 

·         Dry Heat Sterilization

·         Moist Heat sterilization

Dry heat sterilization of an article is one of the earliest forms of sterilization practiced. Dry heat, as the name indicates, utilizes hot air that is either free from water vapour, or has very little of it, and where this moisture plays a minimal or no role in the process of sterilization.
Methods Used: 

·         Hot air oven

·         Incineration or Burning 

·         Flamming 

·         Radiation

·         Microwave

The most used in the medical field is "Hot air Oven"
Moist Heat Sterilization as the name indicates, utilizes hot air that is heavily laden with water vapour and where this moisture plays the most important role in the process of sterilization.
Methods Used: 

·         Water bath

·         Pasteurization (milk)

·         Boilling

·         Steam Sterilizer

·         Autoclave

The most used in Medical Field is "Autoclave" 

CONCLUSION

All living organisms require energy. They can get their energy from multiple sources: organic chemicals(carbon containing compounds), inorganic chemicals and light. Bacteria use organic chemicals, such as, sugars, starch, protiens and fats to grow. Bacteria are called heterotrophs.

Most bacteria grow best at normal, human body temperature (98-99 degrees F). When growing the bacteria, incubate at a temperature as close to this as possible. The bacteria will grow slower at lower temperatures.

Aseptic technique is the process of growing and transferring bacteria without contaminating the culture by touching or breathing on the sample.

Nutrient agar is a general purpose prepared media and grows many types of bacteria and fungi. If you have a specific bacteria culture, you can spread the bacteria on the plate using a sterile swab or innoculating loop. The bacteria will grow and become visible in 24-48 hrs. If you would like to determine the types of bacteria growing on a sink, chair, table or other areas, a sterile swab can be used to rub across the area you would like to test. After the sample is taken, you can transfer the bacteria to the nutrient agar plate by swiping the swab across the surface of the agar plate. After 24-48 hrs, you may find many, different looking colonies growing on the nutrient agar plate. Each type of bacteria look a little different (color, shape, size) when they grow.

REFERENCE

http://www.gadgetscience.com/growing-bacteria-on-nutrient-agar-plates/

http://wiki.answers.com/Q/What_are_the_Advantages_and_disadvantages_of_heat_sterilization_on_medical_equipment