Whole milk was concentrated by a factor of two by ultrafiltration. It was used directly for making Cheddar and Cheshire cheese, an unripened soft cheese of the Coulommier type, and yoghurt. The yields of hard cheese from the concentrated milk were the same as those from normal whole milk. The cheeses were acceptable though the flavour was milder than that of good quality Cheddar and Cheshire cheese. Medium fat soft cheeses were made from the concentrated milk. The yield of cheese was 41 per cent greater than that made from normal whole milk and the making time was half that of the normal process. The cheeses were consumed fresh or stored in deep freeze. For making yoghurt, the usual reinforcement with skim milk powder was not necessary as the concentrated milk had a high total solids content, nor was it necessary to homogenize the mix. The yoghurt contained 21 per cent total solids and was a very acceptable product.

SummaryThe cheesemaking properties of recombinant chymosin from Kluyveromyces lactis (Gist-Brocades Chymosin 610) were Compared with those of standard rennet in parallel trials with the same milk and mixed culture starter. For each pair of cheeses the cheesemaking characteristics, mass balance results, composition of the cheeses at 6 weeks and maturation rates were similar. A taste panel was not able to differentiate between the cheeses at 3, 6 or 12 months.

The effect of reducing the salt content on the meltability and free oil of mozzarella cheese was studied. In addition, the alternative use of a twin‐screw extruder is proposed for the stretching of the curd. It was found that by reducing the salt content the meltability and the free oil are slightly decreased. On the other hand, the cheese produced from the twin‐screw extruder (fed with chilled curd) had lower meltability but no free oil at all compared with that from a conventional stretcher.