the manufacture of yoghurt . Danish dairy increases output . in many European countries such as Switzerland , Holland , Germany and Italy sales of yoghurt have recently undergone a considerable increase , and are even greater as one comes as far south as Turkey and the Balkans , where yoghurt originated . in the Scandinavian countries they have not varied very much , with the possible exception of Sweden , where there has been a market interest in this special cultured milk product . from time to time in Denmark , there has been a move to increase sales , especially when the international weekly and monthly journals have emphasized the health-giving properties of yoghurt . the increase to date , however , has not given rise to much profit , for a considerable turnover and investment in the product is necessary before much return can be expected . when this has been achieved there are grounds for rationalising the product and improving the quality . some time ago an effort was made to sell more yoghurt in greater Copenhagen , and the dairy firm Jaegersborg All&amp;eacute;s Mejeri increased its sales so that production could be rationalised , according to the latest methods . the dairy has now constructed a completely new yoghurt department , equipped with new plant , the most important of which is a large new automatically controlled yoghurt incubator ( fig 1 ) . the incubator is 2 m wide , 1 m deep and 2 m high and holds in all 2,000 quarter-litre yoghurt jars of the type shown in fig 2 , which stand in galvanized crates , 50 to each crate . it is well insulated and finished in stainless steel plate , both inside and out . the conditions necessary for the manufacture of yoghurt of the right quality include a very careful control of all time-temperature combinations throughout the process . the incubator is therefore equipped with a very precise and entirely automatic control , which leaves nothing to chance from the moment the yoghurt jars enter the cupboard till they are removed to the dispatch department . it is easier to understand the function of the automatic control when it is considered in connection with the manufacturing method employed by Jaegersborg All&amp;eacute;s Mejeri , which must not be varied if one is to obtain a uniform product from day to day . the product should have a mild , acid and aromatic flavour . methods of manufacture . stassinized milk is used for the manufacture of yoghurt . the milk is stored overnight at 4 &amp;deg; C , because it has been found that the ageing of the milk , which takes place during this storage period , is important in the quality of the final product . the aged milk is then filled into a 500 l jacketed stainless steel container and heated to 70 &amp;deg; C . it is homogenised at this temperature , using only a light pressure , and is then fed to a second holding vessel , exactly similar to the first , where it is heated to 95 &amp;deg; C in 30 min . afterwards the milk is cooled to 50 &amp;deg; C , at which point 3 per cent yoghurt culture is added . this is thoroughly stirred in , after which the milk is filled in to the new 250 ml jars , with a 55 mm opening designed so that the yoghurt can be eaten direct from the jar . filling is carried out by a Handy 2 apparatus which is fitted with specially designed filling valves for the wide mouthed jars . the yoghurt culture , which consists of a mixture of streptoccus thermophilus and thermobacterium bulgaricum , is particularly sensitive to disinfectants and sodium hypochlorite is not used therefore in the final rinse water during the washing of the jars . instead , the final temperature is raised so that the jars leave the washer hot and dry in a relatively short time . after filling and capping , the temperature of the inoculated yoghurt milk is reduced to 41-42 &amp;deg; C , and the jars are put into the incubator , where this temperature is held constant for approximately 2 hr . supplementary heat is provided by an electric heating element enclosed in the partition wall between the two doors , which is automatically controlled by means of contact thermometers . the temperature is then reduced to 20 &amp;deg; C during the next 2 hr . cooling takes place by means of chilled water and this is also automatically controlled so that the temperature falls evenly . in further period of 2 hr the temperature is reduced from 20 &amp;deg; C to 4 &amp;deg; C , which is maintained until the yoghurt is removed from the cupboard . freezing is carried out by a refrigeration unit mounted above the incubator . this is also equipped with automatic time and temperature controls which are mounted in a separate control panel . the accuracy of control is demonstrated by the rate of acid development which is almost constant from day to day . in the manufacture of yoghurt it is also important to prevent the product from wheying off at any stage , and it is essential that the ripening is stopped at the correct degree of acidity , and the temperature subsequently reduced quickly and evenly . Jaegersborg All&amp;eacute;s Mejeri have chosen to handle yoghurt in the new standard jars because they believe that nothing appeals more to both the eye and the appetite than hundreds of clear , uniformly filled jars standing ready for dispatch . with its new equipment the dairy can turn out 2,000 jars daily , but if the trade continues to expand it will only be a question of time before new equipment is added to that already installed . the manufacturers of the incubator , which is equipped with Faxholm automatic controls , are P Andersen &apos;s EFTF of Copenhagen . supermarket trade association formed . two classes of membership . a trade association has been formed to service the rapidly growing supermarket industry . the founder members are : Neville Cohen of London grocers Ltd , Sydney J Ingram of Anthony Jackson &apos;s Foodfare Ltd , Patrick Galvani of premier supermarkets Ltd , J Prideaux of John Gardner Ltd , T Lennon of Lennons supermarkets Ltd , Lord Trenchard and Wilfred Proudfoot , M.P . the objectives of the supermarket association are : - ( 1 ) to provide a full information service to members . ( 2 ) to represent the industry on matters of legislation , staff and public relations . ( 3 ) to attract the right people into the industry and develop training facilities for them . two classes of membership are proposed : full membership for companies engaged in operating supermarkets - the subscription will be 50 gns a year plus one guinea per branch - and associate membership for manufacturers and suppliers , who will receive the full services of the association but will have no voting powers . subscription for associates will be 100 gns a year . it is hoped to extend personal membership to those engaged in the industry when training facilities are available . members of the industry believe that joint action is necessary to ensure that the growing demand for pre-packed and graded produce can be met . only a united industry can deal adequately with marketing board government departments . staff training , statistical and other information , and the development of good relations with the buying public are all recognised as immediate requirements that only a fully representative trade organisation can provide . Mr Don Parsons , executive director of the supermarket institute of America , has been elected an honorary member . Mr E G Sabatini , manager of promotion features Ltd , has been appointed Secretary to the supermarket association and their offices are at 17/19 Stratford Place , London W.1 ( telephone : Grosvenor 8561/4 ) , where a full service is being provided by promotion features Ltd . monthly digest of world literature . by Ernest J Mann , N.D.D . commonwealth bureau of dairy science and technology . milk drying . considerable technical developments have been taking place in the field of milk drying during recent years and there is no indication as yet that the flow of new ideas and developments in this field is coming to an end . an entirely new process developed on the continent and suitable for drying milk as well as a variety of other foods is the B.I.R.S process , the first detailed description of which has recently been published ( 1 ) . the main object of the process is to remove water from the product to be dried in such a way as to have a minimum effect on the flavour and nutritive value of the original product . this is achieved essentially by drying at a temperature below 30 &amp;deg; C . after pilot plant studies had shown that over 80 different foods , including milk , butter , cheese and yoghurt , could be dried successfully by the process , a commercial plant was built in Sienna , Italy , and is now in operation for the manufacture of tomato powder . the plant consists of a 70-meter high , plastics-lined drying tower , through which particles of the product to be dried fall in counter current to slowly rising pre-dried air flowing at a rate of 0.05 to 1 meter per second . since the drying takes place very slowly at a temperature below 30 &amp;deg; C , little of the aroma and flavour of the original product is lost . the air is dried by passage through chambers containing moisture absorbents and enters the chamber with a moisture content of 3 per cent , leaving it at the top of the tower with a moisture content of 80-90 per cent . the air is also filtered before entering the drying tower , containing not more than 0.5 mg dust per cubic meter and being free from bacterial contamination . the particle size can be varied by regulating the distributor feeding the product into the tower and drying can be extended from 5 sec to considerably longer periods . new plants which have been planned to have drying capacities of 1,000 to 5,000 litres moisture removed per hour and it has been calculated that only 1.2 to 1.8 kg steam are required for the evaporation of 1 kg moisture by the B.I.R.S process , compared with 3.0 to 3.5 kg required in continental spray-drying . the main object of a number of recent American patents appears to be to achieve a powder of higher solubility and/or stability , attention being directed especially to the drying of whole milk . one such process ( 2 ) involves incorporating an inert gas of low solubility into a concentrated , homogenised fat-containing milk in which the fat particles do not exceed 2m , subjecting the concentrate to such conditions of temperature and pressure as will prevent substantial evolution of gas while causing the concentrate to foam or puff , and finally drying the foamed concentrate to produce a dry cellular product which is readily dispersible in cold water by hand stirring . another , somewhat similar , process ( 3 ) involves converting concentrated milk into a stable foam by incorporating a small amount of a foam-stabilising agent ( 1-4 per cent by wt ) and a large volume of air or inert gas . the milk foam produced is then exposed , in the form of a thin layer , at normal pressures to a current of hot gases at 120 &amp;deg; -220 &amp;deg; F until it is dried . during drying , the foam retains its expanded volume with the result that the final product is a brittle , sponge-like porous mass consisting of a matrix of solid milk particles interspersed with pockets of gas . it is readily crushed to form a product of porous flakes which are highly soluble in water . on somewhat different lines is a process suitable for spray-drying whole milk ( 4 ) , which involves spraying concentrated milk into a vacuum chamber and subjecting it to radiant microwave energy at a temperature below 35 &amp;deg; C in the upper section until a solids content of 87 per cent has been reached , after which it is treated by infra-red rays at a temperature below 60 &amp;deg; C until the dried milk particles attain a moisture content less than 5 per cent . the milk particles may also be coated by spraying a hot lactose solution into the lower part of the drying chamber . this imparts improved solubility to the dried milk . improved solubility is also claimed in a process emanating from the Netherlands ( 5 ) , in which spray dried skim- or whole milk is heated to 70 &amp;deg; C in a steam jacketed rotary mixer and 0.2-4 per cent by weight of similarly heated liquified soya-lecithin is added , causing the milk particles to become coated with the lecithin . 