Microbiological expertise

Determination of the parameters for thermal destruction of microorganisms

In this first step, we cultivate the bacterial or fungal strains identified as the target of sterilisation heat treatment applied to the bulk cosmetic products. In the final phase of the cultivation process, the cultivated strains are introduced into the product to be sterilised. Adapting the strains to the final medium enables a close a match as possible to the thermal resistance characteristics of the contaminants found naturally in the product.

The strains selected to be cultivated are processed in TDT (Thermal Death Time) tubes where they are subject to different forms of heat treatment. The destruction kinetics achieved at different temperatures are used to determine the thermal resistance characteristics (decimal time of reduction at temperature θ, Dθ, Z) of the germs of interest in the target matrix.

Once we have determined the thermal resistance parameters for the germs of interest in the water+bulk product type matrix, we are able to scale heat treatment so as to ensure controlled destruction. The destructive effectiveness of the sterilisation heat treatment is then optimised according to the contamination history of the formulas under study, the scale of production and the industrial risk (instability risk) defined by the customer. This optimisation process results in the definition of a target sterilisation value. The full set of sterilisation values (which define destructive effectiveness) thus obtained (target SV or FO) can be used to accurately determine the heat treatment best suited to product sensitivity and the technical possibilities of the production facilities concerned.

Voluntary seeding of micro-organisms in the bulk cosmetic product

Voluntary seeding of micro-organisms means introducing contamination to the bulk cosmetic product while protecting the functional and visual properties of the product as far as possible.
In the first phase, we produce a growth curve for the selected germ(s) to determine their kinetics. When a germ is cultivated, we obtain a sufficient level of concentration of that germ for our UHT sterilisation trials. We then measure the destructive effectiveness obtained for a given germ.

Workshop ecology

The purpose of workshop ecology is to carefully identify contaminant germs, which may or may not be recurring, found in the cosmetic formulas or raw materials.
Samples are taken across the whole workshop. The germs found are then analysed using molecular biology resources.
We can then accurately locate the sources of product contamination and introduce corrective actions.