Phases of the culture media preparation: manual vs automatic preparation
- RAYPA Lab
- 6 min read
- Last updated: 07/05/2026
Table of Contents
Summary
Culture media preparation involves several critical steps, from rehydration to sterilization and dispensing. Traditionally, these steps are performed manually, which can introduce variability and contamination risks.
Automation through media preparators makes it possible to integrate all these stages into a single controlled process, improving reproducibility, safety, and efficiency in the laboratory.
Phases in culture media preparation
In general, the preparation of culture media is carried out manually, which entails certain risks for both the process and the personnel. Among the most common are variations in quality between batches, errors leading to contamination and, in the case of personnel, physical risks such as injuries or burns.
Let us summarize the usual steps involved in the manual preparation of culture media:
1. Preparation
Since most culture media are marketed in the form of freeze-dried powders, they need to be rehydrated.
To do this, the different components must be weighed, placed in a container, poured in the exact amount of distilled water according to the type of container and stirred manually or using a stirrer.
2. Sterilization
Next, the medium needs to be brought to boiling and then sterilization, and these processes are usually carried out with an autoclave.
3. Cooling
After heat treatment, the operator should carefully remove the different containers from the autoclave, as they will be at high temperature and could cause burns.
In the case of agar media, it is important not to allow them to cool completely before dispensing, as the agar gels on cooling.
4. Dispensing
At this stage, the culture medium is distributed in Petri dishes or test tubes.
This can be done manually by decanting or with a dosing pump.
5. Cleaning
The last step in the process is the laborious manual cleaning of the vessels and the dispensing system.
Risks in manual preparation of culture media
As you may already know, manually preparing culture media requires a considerable investment of time, due to the number of tasks involved: weighing the components one by one, adding purified water, waiting for the solute to dissolve, autoclaving the containers and allowing them to cool before dispensing, among other steps.
In addition to the time involved, this process can involve certain risks.
Risks associated with the preparation of the medium:
- Failure to correctly weigh the quantities of the different components.
- Inability to attain a consistent preparation due to challenges in agitation during heating Common problems include air pockets, clumps, incomplete dissolution of solutes and lack of homogeneity between batches.
- Lack of traceability regarding the process performed.
Risks for operating personnel:
- Handling containers with liquids at high temperatures.
- Uncomfortable and repetitive postures during preparation and dispensing. Repetitive tasks which can lead to accidents that, in turn, can result in injuries and temporary or long-term sick leaves.
Preparation of culture media with a media preparator
1. Preparation
The first phase is preparation: selection and weighing of the components and rehydration with purified water.
In the automatic process with a media preparator, the tasks to be performed are the same, but there are some significant differences:
- Both weighing and the addition of water are done with a single operation directly within the equipment and not on a bottle-by-bottle basis. First, the components are added inside the chamber and then the purified water is poured in.
- Heating and stirring of the preparation are carried out automatically, with the possibility of adjusting both parameters according to the specific needs of each formulation.
We can assure you that, with our culture media preparator, you will not only save time, but also significantly reduce preparation errors and occupational hazards.
This is possible, first of all, because the entire process is carried out inside the equipment, in a closed and controlled environment. In addition, the system features:
- Total homogeneity of the prepared volume. Since no individual containers are used, the medium is prepared in a single vessel, which guarantees a uniform composition throughout the volume. Moreover, continuous stirring during the process ensures complete dissolution of the solute.
- Fast and efficient heating. The system allows the entire culture medium to be heated simultaneously, ensuring that the entire volume receives the same heat treatment and reaches a uniform F0. This eliminates the need for multiple autoclaving cycles, where each container may be exposed to different conditions, improving reproducibility and reducing labor times.
2. Sterilization
Sterilization is one of the most complicated phases of the whole process, as it requires a great deal of accuracy and precision. Insufficient sterilization can cause contamination problems, while excessive heat treatment leads to time loss, energy waste and overcooking of the product.
With the AE-MP and TLV-MP Series media preparators, all the disadvantages associated with traditional preparation disappear because:
- La evolución del tiempo y temperatura quedan grabados de manera automática dando la opción de introducir hasta 50 programas de usuario mediante una pantalla táctil de 5" en la Serie AE-MP y 7” en la Serie TLV-MP.
- They incorporate a flexible probe that registers and regulates in real time the temperature of the liquid inside the vessel, allowing precise adjustment of the sterilization temperature. In addition, continuous stirring guarantees homogeneous thermal distribution, ensuring that the entire volume reaches and maintains a uniform temperature during the process.
- They allow sterilization control using the F0 value digitally, which makes it possible to quantify and work with the same sterility objectives, even at different temperatures. This functionality optimizes energy consumption and facilitates work with thermolabile culture media.
- They ensure traceability of the procedure via PC and USB connection, integrated printer, user hierarchy and software, among other options.
3. Cooling
Once sterilization of the culture medium is complete, it is necessary to cool it before dispensing. This phase is particularly delicate due to the high temperatures reached during sterilization, which can reach up to 121ºC, preventing safe handling and representing a risk for the operator.
Moreover, when working with large volumes of liquid, whether in 1L or 200ml bottles, natural cooling can be very slow. For this reason, it is essential that the equipment has a flexible probe, which allows the temperature of the medium to be known precisely.
In addition, the fast cooling system by means of a water cooling coil incorporated in the media preparator drastically reduces the duration of this phase. Also, these devices can maintain the ideal dispensing temperature indefinitely, avoiding gelling of the medium and thus ensuring a comfortable, safe and efficient dispensing phase.
4. Dispensing
Manual dispensing of culture medium carries significant risks. It requires removing hot containers from the autoclave with care to avoid spills and burns, and doing so quickly so that the medium does not gel. In addition, the weight and temperature of the vessels force the operator to maintain awkward postures, increasing the risk of musculoskeletal injuries.
To address these issues, RAYPA media preparators are equipped with an automatic dispensing function, which allows precise, safe and effortless dosing of the medium. The system offers several control modes: by foot pedal, programmed delay or optical sensor, which facilitates a dispensing adapted to the user’s working rhythm. The dispensing speed is adjustable, from 7ml/s to 100ml/s, allowing extremely fast and precise dispensing, according to the needs of the process.
In addition, the dispensing temperature can be adjusted. The dispensing lines can be cleaned and disinfected with continuous steam at high temperature, before, during and after each dispensing phase, thus ensuring aseptic and safe conditions at all times.
5. Cleaning
Unlike the manual method, where the final stage involves complex and time-consuming cleaning of each container and the dispensing system used, the TLV-MP and AE-MP Series media preparators simplify this process by means of automatic cleaning functions.
These machines incorporate a self-cleaning chamber system and multiple cleaning and disinfection options for the dispensing lines, which can be activated before, during and after the dispensing phase. The use of high-temperature steam guarantees complete hygiene without manual intervention, minimizing the risk of cross-contamination, optimizing working times and significantly improving safety conditions in the laboratory.
RAYPA AE-MP and TLV-MP culture media preparators, 5 in 1 equipment
There are many advantages of using RAYPA media preparators. In this article we have described a few of them. Among all its advantages, we highlight the ability to produce, in each cycle and with just one unit, anywhere from 1 to 90 liters of culture medium. In addition, it allows for the fully automatic execution of five process phases: preparation, sterilization, cooling, dispensing, and cleaning of the dispensing lines.
Thanks to its features, ergonomic design, and high functionality, you can minimize the time required to complete the task, improve the quality of the prepared product, have complete control over the process, and reduce the occupational hazards faced by the operators.
Want more information about RAYPA Media preparators?
Do not hesitate to contact us. We will help you choose the model that best fits your needs.
RAYPA Lab
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