Cup sterilisation test: testing of the sterility performance

Verification of the sterilisation process in filling systems for liquid filling

Feb 2023. To check your sterilisation process in liquid filling, the Eurofins Food & Feed Testing laboatories in Germany offer a new effective way, which is quick and safe. The application is suitable for packaging of different materials, such as cups, bottles and screw caps, used in the food sector for filling yogurt, beverages, etc. The method is independent of the type of sterilisation process you use.

Background: sterilisation testing

In order to ensure a constant and high quality of the manufactured products, comprehensive product control and a sound environmental monitoring are essential. To check the internal sterilisation processes of the packaging units during liquid filling, we offer you a standardised method with successive sub-steps. The aim of the cup test method is to check the sterilisation processes in the factory by using spores of the non-infectious germ Bacillus atrophaeus. The individual packaging units are specifically contaminated in our laboratory, processed at the manufacturer's premises and then tested for the effectiveness of the sterilisation process used.

Step 1: shipment of the packaging material

The first step is to discuss with the client what type of packaging materials are involved. The packaging can include cups, bottles, screw caps or lids. The size, shape or material of the packaging are important details that can play a role in planning the experiment. To ensure that the schedule can be carried out as coherently as possible, the number of samples, the required degree of contamination of the packaging and the schedule, including a deadline, are determined in advance. Once these points have been clarified, the client can send the packaging material to the laboratory on the agreed date.

Step 2: controlled contamination

After receiption and registration in the laboratory, the packaging material is inoculated with the previously defined number of Bacillus atrophaeus spores. The spores of this germ are used to check the success of the sterilisation process in the filling plant. It has no influence on the performance of the test whether the sterilisation step is a hydrogen peroxide sterilisation process, a hot air sterilisation process or any other sterilisation process. After successful inoculation of the packaging units, they are sent back to the client. A few additional units are always prepared and sent along, which later function as transport controls

Step 3: sterilisation process

After arrival at the factory, the packaging units should be processed in the corresponding plant as soon as possible. During the processing of the inoculated cups, no filling may take place in the corresponding plant. The inoculated cups and closures are processed in separate runs one after the other. Before the packaging units are sealed, they can be filled with an appropriate amount of saline solution. However, this step can also be carried out later in the laboratory. During the processing, make sure that only trained personnel perform this part of the work on the unit. After completion of the procedure, the packaging units should be returned to the laboratory within 24 hours.

Step 4: verification

After receiving the processed packaging units, they are microbiologically analysed on the same day using an accredited method for total microbial count determination. At the same time, transport controls are examined along with these samples. Based on the results obtained, our laboratory experts determine whether the desired and expected germ reductions have been achieved during the sterilisation process. The results are submitted to the client in a detailed report.

Interested and need more information?

If you would like to find out more about carrying out the special sterility test or have specific questions on this topic, please contact your personal account manager or our expert for sterilisation tests, Thomas Koch.