1. Product Overview
First of all, Mannitol Salt Agar (MSA) is a classic selective solid medium widely used by labs in Europe and the United States. As a professional dehydrated powder supplier, Babio formulates this medium specifically to separate and identify pathogenic Staphylococcus aureus. In addition, this dry agar meets international testing standards for food safety, hospital diagnosis and cosmetic inspection.
For your reference, you can explore our full line of compliant microbiology products, including EP-standard and testing-specific culture media, via our official culture media category page (internal link: https://babiolab.com/culture-media). Meanwhile, all performance verification is conducted referring to authenticated reference strain standards from the authoritative ATCC official website (external link: https://www.atcc.org), ensuring fully credible and repeatable test results.
🖼️ Media finished plate image (Insert image 1: MSA agar plate with yellow & red colonies)
2. Formulation & Core Advantages
To begin with, every liter of finished MSA uses balanced high-purity raw materials. The key ingredient is 75g/L sodium chloride, which builds strong osmotic pressure. As a result, most Gram-negative bacteria and irrelevant staphylococci get inhibited effectively.
Moreover, other nutrients including tryptone and beef extract offer stable carbon and nitrogen sources for bacterial growth. The final pH value stays at 7.4 ± 0.2 under 25°C, so test results remain consistent batch by batch.
🖼️ Raw powder texture image (Insert image 2: Light pink free-flowing MSA powder)
3. Clear Working Principle for Easy Identification
On one hand, peptones supply nutrition to support microbe reproduction. On the other hand, D-mannitol acts as a fermentation marker to tell different staph strains apart.
If the strain is coagulase-positive Staphylococcus aureus, it will ferment mannitol and produce acid. After that, phenol red turns the colony bright yellow with yellow halos.
In contrast, non-pathogenic staphylococci cannot ferment mannitol. Therefore, their colonies stay red without color rings around them.
Finally, agar powder solidifies the liquid medium, making it fit for streak plate culture in daily lab work.
4. Simple Step-by-Step Preparation Guide
Step 1: Weigh out 111.0 grams of dry MSA powder, then add it into 1L distilled water. Next, heat and stir the mixture until all powder dissolves fully.
Step 2: Split the dissolved liquid into flasks or lab bottles. After that, autoclave the liquid under 121°C for 15 minutes to finish sterilization.
Step 3: Right after taking the medium out of the autoclave, shake the bottle evenly. Otherwise, agar will sink and form solid sediment at the bottom.
Step 4: Cool the liquid to around 50°C, and pour it into petri dishes for inoculation use.
🎬 Operation tutorial short video (Insert video: MSA medium preparation operation clip)
5. Strict Batch Quality Control
In order to guarantee reliable test data, every production batch passes full strain verification. We adopt two standard ATCC strains for performance testing.
First test strain: Staphylococcus aureus ATCC 25923. It grows abundantly with typical yellow colonies, and the recovery rate reaches over 70%.
Second test strain: Escherichia coli ATCC 25922. This bacterium gets fully suppressed, with zero visible colony growth.
At the same time, we use TSA agar as a control medium to calibrate strain recovery data.
6. Storage Rules & Shelf Life
For long-term stable storage, keep the original package tightly sealed. Besides, store the powder in a dry space with temperature between 5°C and 30°C.
Keep the medium away from direct sunlight and humid air. Once opened, finish using the powder as soon as possible.
The unopened dry agar has a 3-year shelf life counting from the manufacturing date. If the powder becomes caked, discolored or damp, throw it away immediately to avoid wrong lab results.
7. Lab Safety Reminders
First and foremost, this dehydrated medium is only for laboratory in vitro testing and scientific research. Never apply it to human or animal internal treatment.
While weighing, mixing and disposing waste medium, wear gloves, goggles and other standard lab protective gear. What’s more, follow local microbiology lab safety rules all the time.
8. Suitable Customers & Custom Service
This MSA powder fits multiple testing institutions across EU, USA, Southeast Asia and Africa. It works well for food labs, hospital microbiology departments, cosmetic safety centers and university research labs.
Apart from standard retail packages, we also support bulk wholesale, OEM private label and customized medium formulas. If you need a tailored lab solution, contact our sales team via email g.trade@babioivd.com.
