We are convinced that controlled and responsible use of disinfectants and preservatives is the only way to ensure the sustainable protection of man, materials and the environment. schülke not only manufactures preservatives and disinfectants but also offers Microbiological Quality Management as a holistic approach to achieve hygienically-sound products.
On request we can conduct a thorough Hygiene Audit of your operation, train your staff in hygiene practices, provide advice on factory design and compile detailed hygiene plans for your organisation.
If you are interested in taking a comprehensive approach to preventing microbiological contamination and safeguarding your products and processes then we will be pleased to support you.
If anything is changed, in the formulation, in the raw material quality, in the production process or in the batch size the change has to be analysed to see if it has an influence on the microbial stability of the formulation. The type of non-woven and the ratio between substrate and wet tissue liquid can have a dramatic influence on the efficiency of the preservative system. If the type or even the supplier of the substrate is changed a revalidation is recommended.
Minor ingredient changes can have severe influence on the susceptibility to microbial growth. For example perfume composition can be a synergist to the preservative system; one glycol will reduce the active water value more than another; an extract may contain a biocidal compound where another may not.
The same INCI name does not necessarily mean the same compatibility. Often impurities can lead to more incompatibilities than the chemical itself. For example the change from carbomer in powder form to a liquid form has shown dramatic effects. The liquid material contained sulphite impurities generated from the polymerisation process. These impurities destroyed the Isothiazolinone content used in the preservation system of the end product. Also sulphonates based on the production process can contain high amounts of sulphite.
The different pH values of raw materials have to be adjusted in the finished product. Otherwise the stability can be influenced or pH value can get out of the active pH range of the preservative actives. The upgrading of a formulation to a larger batch size is not only critical for the galenic properties of emulsions. The bigger batch size leads to a longer heating period which means a good sanitation of raw material contamination but also a possible destruction of biocides.
The longer cooling period can lead to growing conditions for microbes before the preservative is added but also to a better distribution of the preservative in the water phase caused by the longer stirring time. Normally the microbiological challenge test is done during the development of a formulation. A re-validation should be performed with the first production batch. Each change should be secured by a new microbiological test.