Nutrient Broth is a basic media composed of a simple peptone and a beef extract. Peptone contributes organic nitrogen in the form of amino acids and long-chained fatty acids. Beef Extract provides additional vitamins, carbohydrates, salts and other organic nitrogen compounds.

The most common growth media for microorganisms are nutrient broths (liquid nutrient medium) or lysogeny broth medium. Liquid media are often mixed with agar and poured via a sterile media dispenser into Petri dishes to solidify. These agar plates provide a solid medium on which microbes may be cultured.

A microbiological culture medium is a substance that encourages the growth, support, and survival of microorganisms. Culture media contains nutrients, growth promoting factors, energy sources, buffer salts, minerals, metals, and gelling agents (for solid media) [2].

Enriched media contain the nutrients required to support the growth of a wide variety of organisms, including some of the more fastidious ones. They are commonly used to harvest as many different types of microbes as are present in the specimen. Selective media are used for the growth of only selected microorganisms.

Agar is an ideal solidifying agent for microbiological media because of its melting properties and because it has no nutritive value for the vast majority of bacteria. These bacteria would eventually grow and flourish if the medium were not sterilized, that is, if these unwanted microbes were not destroyed.

Nutrient agar is a general purpose medium supporting growth of a wide range of non-fastidious organisms. It typically contains (mass/volume): 0.5% Peptone – this provides organic nitrogen. 0.3% beef extract/yeast extract – the water-soluble content of these contribute vitamins, carbohydrates, nitrogen, and salts.