Factory hygiene

Disinfection and preservation of equipment

Efficient factory hygiene solutions

for the production of water-based products

Efficient factory hygiene solutions require close collaboration of operating parties, the biocide supplier, and the plant engineering specialist.

To many producers of water-based products the factory hygiene becomes more and more challenging. It is not only the in-can preservation of the products, which becomes more and more challenging, but also the disinfection of production lines. Here, it is essential to keep the microbiological load on the product as low as possible already during production.

Factory hygiene is not only improved by using new technologies or new agents but rather by a concerted action of the operating party, the biocide supplier, and the vendor of the line. Each of these players with its corresponding view and experience has an important contribution to made to the holistic solution. The operating party benefits from the facts that the quantity of agent to be used becomes reduced to a minimum whereas the microbiological safety of production becomes increased.

DMK-Modul der OAS AG
DMK-Modul der OAS AG
DMK-Modul der OAS AG

Requirements by law

complying with the CLP Regulation

  • In addition we have to comply with the requirements by law regarding the agents and quantities of agent permitted in finished products. The CLP Regulation (EC No. 1272/2008) reduced the limit values for sensitising agents as per 01 June 2015. Should this concentration be exceeded, a corresponding information (EUH208 statement) for allergic persons shall be shown on the packaging of products including such substances. Furthermore, formaldehyde was subject to reclassification: as per 01 January 2016, HCHO of 0.1 % up shall show the hazard statement H350 "May cause cancer ".

    Both statutory regulations lead to a reduction or even to avoidance of the quantities of agent used. Therefrom resulted gaps regarding the microbial product safety, which have to be compensated with an increased expenditure in production hygiene. However, the use of reactive substances involves an increased hazard to cause harm to the corresponding employee's health: it is absolutely required to prevent any contact with these sanitising solutions or at least to keep the risk of contact as low as possible. Here, constructional measures can be taken or adequate equipment along with operating instructions and sequences can be used to reduce the hazard during handling.

    Only a concerted proceeding of the operating party, the producer of preservatives, and the specialist in plant engineering familiar with the subject will lead to a lasting success. Already a single area where the measures taken are insufficient or wrong could undermine all sanitising and preserving efforts.

Risk assessment

The risk assessment of different plant areas leads to a multitude of parameters to be taken into consideration:

  • temperatures,
  • hygienic conditions around the units,
  • cleaning condition of the line,
  • storage time of the products in the line,
  • bacterial counts of raw materials,
  • chemicals used, etc.

Due to the complex combination of the different factors, a plant inspection carried out by the three parties has been proven successful in practice. Thereupon, they prepare a comprehensive catalogue of measures to increase the microbiological safety of production.

Techniques often used

Solutions with different concentrations of the agents are fed to the line to sanitise them. These solutions shall be applied all over the open surfaces of the units, such as containers, tanks, mixers, dissolvers. In general, it should also be possible to sanitise filled units.

Many operators still use mobile atomisers to this end. This has the known adverse effects of a limited reach of the atomising gun and of a poor reliability that all surfaces are evenly wetted. And it should not be disregarded that this implies a potential harm to the health of the persons carrying out this job.

For an installation of stationary spray nozzles underneath the covers of receptacles, it is to be taken into account that some areas or components are laying in the spray shadow: they cannot be reached at all or only by means of elaborate technology. A large part of the solution directly enters the stored product without being able to become operative before. Furthermore, the surfaces of the receptacles are wetted to a limited extent only as the surface tension causes the agent to run off the walls in delta shape (see photograph).

Stationary atomising nozzles, which by contrast produce an aerosol or drizzling fog, only show limited effect due to the saturation behaviour of air. At a temperature of 20 °C, one cubic metre of air binds just over 17 g of water. Anything beyond this limit will rain down onto the product surface. Sufficient application of the agent onto the surfaces without any significant entry into the product is hardly possible with such a static fog.

Factory hygiene solutions

There are several approaches allowing the operating party to look at the factory hygiene in its entirety and to strongly increase the microbiological safety in production.

  • The cooperation of operating parties with a producer of biocides and OAS AG has lead to an alternative approach regarding the use of the agents, which holds the advantages below:

    • no contact of operator and agent
    • alternative use of different agents and concentrations
    • application of the least possible quantity of an agent
    • even application on all surfaces in the units
    • no mobile parts inside the units
    • application on filled units possible

    The DK module (DK is the German abbreviation of „disinfection and preservation“) features a nozzle tip, which the operator can easily install into the unit by means of a tight-closing 3"-tank lorry coupling of commercial quality.

    The nozzle tip generates turbulent airflows in the unit, into which an aerosol is injected. The aerosol is moved at high-speed, what causes that it deposits when coming into contact with the surfaces. As the flows are directed upwards as well, even the underside of horizontal surfaces are wetted.

    The DK base module housing the pneumatic control unit and the conveying pumps provides for supply to the nozzle tip. The control unit processes a sequence to ensure a reproducible proceeding.

    Designed as a mobile unit, disinfecting can be carried out at different locations in production and at as many units required.

    Wipe tests at defined spots in numerous applications proved the effectivity of the DK module. The supplier of the biocide offers the service to support the operating party regarding microbiological issues and laboratory analyses. The Thor Company analysed the samples in its laboratories and compared the different application cycles. During these examinations, the samples were analysed regarding bacteria, in particular pseudomonas, as well as regarding yeast and mould.

    It quickly turned out that the use of the DK module had provided for a re-use even of heavy-loaded units already after a short time of application.

  • Sanitising of the units was definitely impeded at spots showing many coats of material on the walls or around the covers of receptacles.

    Within the scope of the overall examination of hygiene, there are design measures which can be taken to considerably reduce such build-up of coats. These are for instance:

    • conditioning of the incoming air by means of air treatment systems
    • position of agitator blades
    • design of the product feed
    • examination of the run-off behaviour
    • organisational measures regarding the material handling

    Sanitising of the units was definitely impeded at spots showing many coats of material on the walls or around the covers of receptacles.

  • In ideal circumstances, the control and documentation of factory hygiene is an integral part of the process control system, which also supports consistent and batch-oriented material postings in production.

    First of all, it should be possible to assign the units to a risk assessment. School marks can be given to different risk parameters, such as the surface quality, dead volumes, and aspiration. Moreover, risk coefficients are assigned to raw materials. The control system takes these and other relevant parameters (ambient temperature, dwell time, etc.) to determine the risk class of each unit. A colour display on each unit dynamically shows the current hygiene status.

    In addition to the usual production recipes, the process control system can also manage disinfecting recipes, which may include manual components and automatically dosed components. When preparing the sanitising/disinfecting order, the dosing quantity of agents can be adjusted to the current fill level of a container if required. The operator has to acknowledge manual procedures. The system stores the corresponding disinfection logs.

    Furthermore, it provides for managing the sampling orders for each unit. Here, the date and the exact specification of test spots is stored. Subsequent to sampling, laboratory results can be entered at the workstation in the laboratory itself.

    Since the agents used migrate into the raw materials or the finished products, the automatic material posting includes them as a mixing batch. Thus, they are part of the batch log too. Agents which become neutralised after a short time, can be excluded from batch logging.

    A unit log sums up all relevant data. These are among other things:

    • graphical representation of fill levels and other analogue values (e.g. temperatures) on an ongoing basis,
    • laboratory values of samples,
    • disinfection logs,
    • batch postings in the unit.

    Other relevant complementary data, such as the AOX value of waste water, can also be logged in a journal. These are part of the higher-level hygiene log, which summarises unit logs and disinfection logs for the entire plant.

    Conclusion regarding an improved factory hygiene

    Factory hygiene is not only improved by using new technologies or new agents but rather by a concerted action of the operating party, the biocide supplier, and the vendor of the line. Each of these players with its corresponding view and experience has an important contribution to made to the holistic solution. The operating party benefits from the facts that the quantity of agent to be used becomes reduced to a minimum whereas the microbiological safety of production becomes increased.

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DK Modul
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