Plate Count Agar (Standard Plate Agar)

PRODUCT SUMMARY AND EXPLANATION

Plate Count Agar (PCA) is a general-purpose medium used for the counting of viable aerobic bacteria. It is also known as Standard Plate Count Agar. It is suitable for the counting of viable aerobic bacteria in food, water, milk, dairy products, and other materials. It is a favourable medium for the analysis of the total microbial load of raw and end products.

This medium facilitates the growth of a broad spectrum of non-fastidious microorganisms like aerobic and facultative anaerobic mesophilic bacteria. Casein enzymic hydrolysate (tryptone), yeast extract, and glucose are present in it, which are amino acids, peptides, vitamins, and carbohydrate sources necessary for microbial growth. The well-balanced composition facilitates luxuriant growth and morphological differentiation, which are necessary for proper counting of the colonies.

This agar is commonly used in the food industry for enumeration of total viable count (TVC), usually as part of quality control analysis of dairy, meat, beverage, and bakery food. In water analysis, it is employed in the standard bacteriological evaluation of drinking and recreational water sources. It is also employed in surface and environmental monitoring of pharmaceutical and cleanroom facilities.

On this medium, the samples are inoculated by pour plate, spread plate, or membrane filtration methods. Colonies are enumerated after incubation at room temperature—e.g., 30°C for food or 35°C for water—before they are quantitated in terms of colony-forming units (CFU) per milliliter or gram of sample.

Plate Count Agar offers reliable results, clear appearance, and rapid recovery of aerobic bacteria from many types of samples. Ease of use and supporting nature for the majority of microbial growth make it an essential tool for microbial counting in quality control laboratory test work and regulatory testing.

PRINCIPLE
The medium consists of Tryptone which provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly the B-group. Dextrose is the fermentable sugar providing carbon and energy. Agar acts as a solidifying agent.

QUALITY CONTROL SPECIFICATIONS

Appearance of Dehydrated powder : Cream to yellow, homogeneous free flowing powder.
Appearance of Prepared medium : Light yellow colored, clear to slightly opalescent gel.
pH (at 25°C) : 7.0± 0.2