Possible influence of surfactants and proteins on the efficiency of contact agar microbiological surface sampling.

Agar contact microbiological sampling techniques, based on a transfer of the microorganisms present on a surface to a culture medium, are widely used to assess and control surface cleanliness and to evaluate microbial contamination levels. The effectiveness of these techniques depends on many environmental parameters that influence the strength of attachment of the bacteria to the surface. In the present study, stainless steel and high density polyethylene surfaces were inoculated with known concentrations of Staphylococcus epidermidis.

Physico-chemical mechanisms governing the adherence of starch granules on materials with different hydrophobicities.

The factors influencing the adherence of starch were examined to improve the understanding of the mechanisms affecting soiling and cleanability. Therefore an aqueous suspension of starch granules was sprayed on four model substrates (glass, stainless steel, polystyrene and PTFE) and dried, and the substrates were cleaned using a radial-flow cell. The morphology of the soiled surfaces and the substrate chemical composition were also characterized.

Hygiene and cleanability: a focus on surfaces.

Hygiene is a permanent concern for food industries since they must commercialize high quality products in order to comply with the legislation and the expectations of the consumers. The hygienic state of a surface is thus a critical parameter with respect to the performances of the production process and to the final quality of the product. For this reason, cleaning and disinfection are essential.

Biocatalytic production of enantiopure cyclohexane-trans-1,2-diol using extracellular lipases from Bacillus subtilis.

Two extracellular lipases from Bacillus subtilis, B. subtilis lipase A and lipase B, have been expressed in the heterologous host Escherichia coli, biochemically characterized and used for the kinetic resolution of (rac)-trans-1,2-diacetoxycyclohexane. Both enzymes were selectively acting on the (R,R)-enantiomer of the racemic substrate, highly specifically hydrolyzing only one of the two ester groups present, thus allowing the preparation of enantiopure (R,R)- and (S,S)-cyclohexane-trans-1,2-diol.