Investigation of curd grains in Swiss-type cheese using light and confocal laser scanning microscopy

The mechanisms of eye growth in Swiss-type cheeses have mostly been explained empirically. Greater understanding may be needed to anticipate structural changes that may lead to cracking instead of bubble formation. The microstructure of a Swiss-type cheese was therefore investigated using a multi-scale approach. Two techniques were used: light microscopy to study curd grain patterns, and confocal laser scanning microscopy (CLSM) to study the organisation of the fat and protein network in the cheese matrix around eyes. Anisotropy was revealed according to the direction of examination, with a different organisation of curd grains along or perpendicular to the pressing axis of the cheese. The curd grains appeared to be highly stretched around the openings. CLSM revealed a difference in composition inside curd grains and at the surface of eyes. Moreover, holes were observed at the interfaces of the grains, possibly corresponding to small eyes or to the origin of cracks.