# Plate Count Agar

> non-selective microbiological growth medium

**Wikidata**: [Q6395830](https://www.wikidata.org/wiki/Q6395830)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Plate_count_agar)  
**Source**: https://4ort.xyz/entity/plate-count-agar

## Summary
Plate Count Agar is a non-selective microbiological growth medium. This means it is a gel designed to support the growth of a wide variety of microorganisms, rather than selecting for a specific type. It is commonly used to count the total number of viable bacteria present in a sample.

## Key Facts
- **Classification:** An instance of a growth medium.
- **Primary Characteristic:** Non-selective, meaning it is formulated to support a broad range of microorganisms.
- **Composition:** Contains 0.5% tryptone, 0.25% yeast extract, 0.1% glucose, and 1.5% agar.
- **Alias:** Also known as 標準寒天培地 in Japanese.
- **Documentation:** Has a Wikipedia article titled "Plate count agar" and is documented across 7 languages on Wikimedia projects.

## FAQs
### Q: What is Plate Count Agar made of?
A: Plate Count Agar is a gel-based medium composed of four main ingredients: tryptone (0.5%), yeast extract (0.25%), glucose (0.1%), and agar (1.5%). Tryptone and yeast extract provide the necessary nutrients for microbial growth.

### Q: What does "non-selective" mean for a growth medium?
A: A non-selective medium is designed to support the growth of a wide variety of microorganisms. Unlike selective media that inhibit certain microbes to isolate others, Plate Count Agar provides general nutrients that allow most common bacteria to grow.

### Q: What is a growth medium?
A: A growth medium is a liquid or gel substance containing the nutrients required to grow microorganisms or cells in a laboratory. Plate Count Agar is a specific, widely used example of a gel-based growth medium.

## Why It Matters
The significance of Plate Count Agar lies in its non-selective nature, which makes it a standard and versatile tool in microbiology. Because it doesn't inhibit most common bacteria, it is widely used to determine the total microbial population in a sample. This is crucial for quality control in industries like food and water safety, where monitoring the overall number of viable bacteria is a key indicator of contamination or spoilage.

By providing a standardized, reproducible environment for general microbial growth, Plate Count Agar allows scientists to get a reliable "plate count," an estimate of the concentration of microorganisms. Its simple, defined composition ensures that results are comparable across different labs and experiments, making it a foundational medium for quantitative microbiology.

## Notable For
- **General-Purpose Growth:** Its non-selective formulation is designed to support the growth of a broad spectrum of common microorganisms without favoring specific types.
- **Standardized Composition:** It is defined by a specific recipe of tryptone, yeast extract, glucose, and agar, ensuring consistency and reproducibility in microbiological testing.
- **Use in Enumeration:** The name "Plate Count Agar" directly reflects its primary application: enumerating the total number of viable microorganisms in a sample.

## Body
### Classification and Use
Plate Count Agar is classified as a **growth medium**. It is specifically a **non-selective microbiological growth medium**, meaning it is formulated to support the growth of a wide variety of microorganisms rather than inhibiting some to favor others. This property makes it ideal for determining the total microbial load of a sample.

### Composition
The standard formulation for Plate Count Agar consists of the following components by percentage:
- **Tryptone:** 0.5%
- **Yeast Extract:** 0.25%
- **Glucose:** 0.1%
- **Agar:** 1.5%

### Naming and Identification
- **Primary Name:** Plate Count Agar
- **Alias:** In Japanese, it is known as 標準寒天培地.
- **Wikimedia Title:** Its English Wikipedia article is titled "Plate count agar", and it has a corresponding Wikimedia Commons category.