Agroscope, Institute for Plant Production Sciences IPS, 1260 Nyon, Switzerland

Cultures for reducing the stickiness of smeared cheese surfaces

“Numerous traditional Swiss cheese varieties are smear-ripened e.g. Gruyère, Raclette, Appenzeller and Tilsiter. The smear is a very complex ecosystem composed of moulds, yeasts and bacteria. It contributes to the typical flavour of these cheese varieties. In recent years, the occurence of a defect, the so-called stickiness of the smear, has increased. The smear became bright and viscous like honey during ripening. The consequences were an alteration of the typical flavour and a very labour-intensive handling of the cheeses.Different measures, deduced from practical experience, were taken against the symptoms of the stickiness:<br>- Warmer and less humid climate in the ripening rooms<br>- Lower salt content and pH-value in the water used for smearing<br>These measures permit the cheese producers to fairly control the stickiness, but the cause of the defect still remains unknown.Since practical experiences showed that cheeses with a natural growth of white moulds never became sticky, a lot of isolated moulds were screened for their ability to reduce stickiness. The best effect was obtained with the mould “”P. Anticollanti”” (phantasy name):<br>- an accelerated drying of the cheese surface after smearing<br>- growth of a white mould, without discoloration during ripening<br>- a significant reduction or even a disappearance of the stickiness<br>A strain of Geotrichum candidum showed a similar, but less distinct effect.Based on DNA sequences, there is a reasonable possibility that “”P. Anticollanti”” represents a new species. The comparison of sequences of “”P. Aanticollanti”” with sequences of moulds, which are naturally growing on “”normal”” smear indicate, that “”P. Anticollanti”” is quite common.The defect of the sticky smear shows again how difficult it is to maintain or recover a natural balance of a complex ecosystem.”

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