Spiral Plating is a two-in-one method that enables dilution and plating at the same time. This is an official method of the APHA, the AOAC, and recognized by the FDA BAM (Chapter 3), which main benefit is the incredible gain of time and reduction of Petri plates waste compared to traditional plating methods such as spread plate, pour plate and drop plate.
Click here to read how Jarvis et al. explain that spiral plate method requires only 31% of the labor necessary for the drop count method.
IUL’s Spiral Plater: Eddy Jet 2W
This rapid plating consists of inoculating a known volume of liquid sample on the surface of a rotating agar plate. The volume of the sample decreases as the syringe is dispensing from the center to the edge of the rotating plate describing an Archimedean spiral. In this way, a Spiral Plating such as IUL’s EddyJet 2W creates a threefold decimal dilution in a single plate.
The microbial concentration is determined by:
- Counting the colonies on a part of the Petri dish where they are easily countable
- Dividing this count by the appropriate volume.
Which microbiological laboratories are benefiting most from the use of a spiral plater for bacterial determination?
Spiral plating’s main application is that of performing surface spreads for viable microorganism enumeration where a single spread can have a detection range between 25-250 CFU/plate according to the FDA Bacterial Analytical Manual.
This application is mainly used to assess bacterial concentrations during and after the manufacturing or processing of food, drinks, pharmaceuticals, and cosmetics. It is also widely implemented during challenge testing (also known as preservative efficacy testing).
This method has also been applied to test environmental water samples. Agricultural and environmental industries implement spiral platers in bio-pesticide challenges, frost prevention, and leaf studies.
Eddy Jet 2W, a unique Spiral Plater
The core feature of Eddy Jet 2W is the use of high-precision disposable micro-syringes. Micro-syringes have a capacity of 110 µL and deliver extremely precise volumes of samples to agar surfaces. Being single-use, the syringes do not require to be disinfected and therefore do not generate false-negative or false-positive cases. The Eddy Jet 2W does not only bring high sensitivity but is also very user-friendly and intuitive.
Once incubation is done, the next step will be bacteria counting with the use of a grid for easy reading. Or, for making the most of this automation, you can choose to enumerate the colonies with the automatic colony counter SphereFlash which will give you the result with utmost accuracy in only 2 seconds.