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Post published on 26/03/2021

Interview with Elia Rabaev: Hygiene classes and germ reduction

How is microbiological safety of hygienical filling machines tested?

All hygienic and aseptic systems are subject to so called Challenge tests according to the VDMA regulations. In the Challenge tests the microbiological effectivity (log reduction) of aseptic systems with packaging germ reduction is determined. In this process artificially contaminated packages undergo the decontamination process in the system under controlled conditions. The determination of initial and final germ count enables the logarithmic germ destruction rate to be documented.
In our company the test is carried out before the machine is delivered and all the test material is examined in our own laboratory. Furthermore, we can carry out these tests also at the customers’ site.


Are the hygiene levels related to the product? Do certain products have minimum hygiene requirements? 

The hygiene level of the machine is determined by the type and the required shelf life of the product. The filling system is not able to improve the quality and shelf life of the product which will be packaged but merely maintain them as they are. If very sensitive products with a long shelf life and noncritical products are filled on the same filling machine, a machine in aseptic execution is highly recommended.


How can the germ count be determined?

Depending on the sample there are numerous biological methods. These include microscopic examination, growth simulation and dilution series. In our laboratory we prepare petri dishes, incubate them and count the colonies after growth.


Is one filling machine suitable for various hygiene classes or are these fixed for one hygiene level? 

Each filling machine has specialized equipment that are correlated with the hygiene level of the product to be packed, e.g. filling in a sterile air environment, sterilization of the fillers system etc. If you are considering a new or special product we would recommend an upgrade to a system with a higher hygiene.


What must a customer do to guarantee the standards of the relevant hygiene specifications?

The producer of the filling machines can only give recommendations concerning the installation environment and positioning of the machine. These measures must be determined in the HACCP of the user. We will be glad to assist the user in the regulations of HACCP.


How does the cup leakage work? 

Basically we measure the sealing effectively of the lid (sealing) foil in time. This is necessarily a continual process to locate tiny holes in the foil. In the case of tiny holes the foil will elevate for a few seconds and then collapse. If the cup is stable the sealing mechanism remains stable during the entire measuring process.

There are two methods we use to increase the pressure in the cup:

  • Heating the head of the cup by using heating elements on the foil
  • Squeezing the cup.

The nature of the packaging and its contents determine which method is suitable.


How does sterilization of cups and lids work?

Sterilization of cups and lids on our aseptic fill and seal machines is a chemical process. An aerosol of hydrogen peroxide is applied onto the packaging material and is dried in the next step at the according temperatures. This means the decontamination rates up to LOG 6 using the relevant bioindicator can be achieved with low peroxide concentrations in the packaging.


How are the germs killed off?

There are many physical, chemical and combined methods to kill off germs on surfaces each working in different ways. The use of dry heat or steam inactivates microorganisms thermically.

Using chemical methods with hydrogen peroxide the oxygen radicals cause various kinds of irreparable damage in the cellular structure of the germs. The enzymes, membrane components and lipids are oxidized and thus inactivated. The cellular plasma is destroyed.

UV radiation deactivates microorganisms by damaging the DNA and preventing reproduction.


Can the optimization of hygienic conditions lead to the disuse of preservatives?

Should the customer decide to reduce preservatives in the products, it, the quality of the product and the hygiene level on the production line must be optimized. This can be enabled by the implementation of UV-cassettes or spray disinfection. Hassia will be glad to give advice in the optimization of the production line and upgrading the system.

Elia Rabaev

Teamleader Aseptic Competence Center & Process Technology at Hassia Verpackungsmaschinen GmbH