CLEAN CREAM

Press, Volume LXX, Issue 21179, 1 June 1934, Page 7

CLEAN CREAM

HOW TO PRODUCE IT IMPORTANCE IN RETAINING MARKETS CHAMBER OF COMMERCE BULLETIN The May agricultural bulletin prepared by Canterbury Agricultural College for the Canterbury Chamber of Commerce deals with clean cream production. It sets out that improved quality is essential if New Zealand is to retain her markets and to secure top prices for her butter. The quality of the butter provided is dependent primarily on the greatest possible cleanliness in the cream supplied, it says, and it is the purpose of the bulletin to show how every dairy farmer can supply such cream and can receive the incentive that will make his effort worth while. The bulletin reads:— Paying on Quality The producer of clean, wholesome cream secures some encouragement in that a higher price is paid for the best orcduc'i. Cream js usually graded into three classes—finest, first, and second grade. In New Zealand, where reliance is placed on the sensory tests such as taste, smell, appearance, etc.. it is difficult to avoid variation in standards of grading. In other countries more scientific methods of grading are adopted, and the adoption of similar methods might be of advantage here! On its arrival at the factory the cream is pasteurised, and although effective pasteurisation kills most of the bacteria in cream it does nothing to encourage the production of clean cream or to correct changes which have taken place before the cream reaches the factory. The practice adopted in some factories of mixing the different grades of cream to make one grade of butter seems to be another weakness in the manufacture of the finest quality product, which discourages the farmer from improving his quality. It appears, therefore, that although producers of "finest" cream, receive some extra return, a better price could bo paid them if their cream were manufactured into butler of the grade and were never mixed with cream of lower grades. If paid on standardised quaiity, measured by scientific methods, the producers of clean cream would benefit considerably. Higher prices then, depend largely on the production of cream of the highest quality. Low quality cream results in low grade butter, which depresses the price of all the butter exported. The production of finest qualitj' in--1 volves great care in cooling, storing nnd transporting the cream as well as | the utmost cleanliness in the milking j and separating processes. These are discussed in detail below. Cooling: the Cream All the precautions taken to produce clean cream on the farm will be of little avail unless the cream is cooled at once. As it leaves the separator the cream has a temperature of about 78 degrees F. ( and at this temperature the bacteria which have gained entrance increase at a rapid rate. The object of cooling is to retard this bacterial increase. The effect of a reduced temperature on bacterial development in a sample of cream which contained two million bacteria a cubic centimeter, at the beginning of the test, is shown in the following table.

Number of Bacteria per c.c. (microscopic counts) In Cream held for Different Periods.

This table clearly shows that the cooler the cream the lower is the number of bacteria. By the ordinary cooling methods and by using water from races or artesian supply, or from tanks exposed to sun, it is difficult in summer to cool cream below COdeg. F. This temperature is much too high, especially if the cream stands two or three days before delivery. A temperature of at least as low as 50 deg. F. should be aimed at, but in order to obtain this some form of ice or of mechanical refrigerator will be necessary. ' Extensive enquiries have been made concerning the costs of refrigerators suitable for the dairy farmer in New Zealand, but owing to there being little demand for this purpose the cost is high at present. In America such refrigerators cost between £2O and £BO according to the capacity. The running cost per day of ice refrigerators is about 7d, and of mechanical refrigeration is about 3d per 10 gallons of cream kept cool. Deterioration During Transit Reference to the above table illustrates clearly how the bacterial eontent of cream may be substantially increased by failure to store it in cool surroundings. The longer the period between separation and delivery at the factory the greater the need for some efficient cooling system for cream during storage on the farm. On most farms facilities for cooling the cream following separation and during storage are lacking and this constitutes a serious weakness in New Zealand's methods of cream production. Cream exposed in cans to the hot sun deteriorates both through rapid bacterial growth and also through chemical changes in the fat. The dirtier the cream the greater is the deterioration. Cream deposited on loading banks, railway stations, etc., should be protected from high temperatures. Very useful insulated shelters can be cheaply constructed for use on farms, collecting depots and railway stations. Railway trucks carrying cream should be insulated or ventilated and cream on lorries should be effectively protected from the direct heat of the sun. Care on the Farm 1. Sterilisation. Besides efficient cooling, cleanliness is essential if cream with low bacterial content is to be produced. It must be clearly understood that cleanliness means more than freedom from visible dirt. It means freedom from injurious bacteria as well. This condition cannot be obtained by-the ordinary methods of washing utensils first in cold, and then in hot water. Washing treatment must be followed by some effective sterilising treatment such as immersion in boiling water, scalding with steam, or by treatment with one of the chemical chlorine disinfectants discussed in bulletin No. 27. Some factories are now supplying chlorine disinfectants to their suppliers, and this practice is to be strongly recommended. Caustic soda or washing soda, while being good cleansing agents, are not good disinfectants when used in the concentrations usually recommended (one to two tablespoonfuls to four gallons of hot water). .

2. Milking.—Milking should be done in sanitary, well venj.ilated sheds. The floor of the shed should be of concrete, impervious, and be thoroughly washed with plenty of water after each milking. The floor of the yard should be well drained, preferably made of concrete, and should be cleaned regularly. The udder and flanks of the cows must be kept clean, free from long hair, and wiped with a damp cloth before milking to remove any dirt and loose hair. Owing to its high bacterial content it is advisable to discard into a separate bucket the first milk from each teat. This precaution also facilitates the early detection of mammitis. The dust nuisance in the shed ana yard can be largely eliminated by hosing down before milking. The cows should not be fed while in the bails and the milkers should be encouraged to take pride in keeping cows, the shed, and themselves in a clean and hygienic condition. Dry milking is to be preferred. Particulars of design of shed and yards aud arrangement of plant may be obtained from the "New Zealand Journal of Agriculture" for December, 1931. 3 The Milking Machine.—When tlie milking machine is properly cared for very little contamination will result, but if the machines are not thoroughly cleaned and sterilised .after each milking serious contamination will take place. Cleaning the Machine After milking, wash off all milk and dirt from the outside of the cups and tube system and then draw one or two gallons of clean, cold water through the end of the milk pipe and through each unit, dousing the. cups in and out of the water during the process, to allow air and water to pasa tXS altexjatoly. This « mmb more effective than cQnsiant waje suction, and removes most of the muh. from the inside of the cups and tubes. For each set follow the cold water with at least a gallon of hot water containing washing soda ° l other cleansing pQwder This re TYinvp"? the fat and other resi , due These two operations wash the milk system. It must now be, sterilised, by drawing either at least one gallon of boiling water, or preferablyhalf a gallon of chlorine solution, through each unit and through the end of the milk pipe. . The vacuum system must ;also be clea'ned and sterilised with boiling water or chlorine solution at least once a week. Faulty inflations and rubber connexions are the main cause of a dirty vacuum system, so that these must be kept in good order and renewed when necessary. . After washing and sterilising the milk system the cups and tubes should be disconnected and immersed in a crock of sterilising solution until next milking, care being taken to exclude air from the tubes while they are being immersed. If chlorine disin-1 fectant is not used .the cups and tube system should be immersed in boiling water for five minutes, and then hung up to dry in a cool, clean place. The releaser and vacuum tank should be taken apart and washed thoroughly, in cold and then hot water containing a cleansing powder. After this they should be sterilised with either boiling water or steam, and then allowed to drain and dry on cool, clean racks. The vat should be similarly treated. Just before next milking draw fresh clean, cold water through the machines and separator to prevent milk adhering to dry surfaces. Cold chlorine solution in place of cold water is an additional safeguard against contamination.

Another Source of Contamination * 4. The Separator—This is just as !J common a source of contamination as £ the milking machine if it is not pro- - perly treated. After each milking it •*. must be taken apart and thoroughly ; washed and sterilised by the methods • described for the milking machine • parts. Clean water or chlorine disin- i fectant should be run through before ; separating begins. 5. Utensils—Utensils and accessories , such as coolers, mixers, buckets, and ; cream cans must each receive as care- - ful attention as the milking machine and separator. Cream cans are washed, and sterilised at the factory, but their after treatment is frequently unsatisfactory. At the farm the cans should ; be disinfected before being used again by rinsing with chlorine solution or by scalding with boiling water or steam. Rusty utensils militate against efficient cleaning and sterilisation, so that all surfaces which come in contact with the milk or cream should be kept in perfect condition. 6. Sundry Precautions—lt is often \ necessary to add cream from successive [ milking to the' same can. It ■is important to realise that the fresh, supply should not be mixed with the pre- ' vious supply until it has been cooled, [Otherwise it will raise the temperature and favour bacterial activity. [ The cream must also be thoroughly mixed with a metal stirrer at least twice a day to minimise the effect of prolonged exposure of one surface to the atmosphere. A wooden stirrer should not be used as it harbours bacteria. Cream should be stored in a clean, odourless room and covered with a wire gauze over which is placed ' clean cheese cloth. Conclusion It is clear that improvement in the quality of butter is largely in the hands, of the dairy farmer. A powerful motive for improved quality could be found in a more scientific system of grading, combined with the making of butter from the different grades of cream. With this system in operation and with a gradual advance in the standards for different grades of cream the farmer would be encouraged to inr"" the extra trouble and expense required to produce cream of the highest quality. Unless those producing and handling dairy produce are prepared by methods such as these to make every effort to produce cream of the highest quality, we cannot hope to compete successfully in the world's market. Copies of the Bulletin may be obtained from the secretary, Canterbury Chamber of Commerce, P.O. Box 187. Christchurch. -

Time of Holding 48hrs. Tempera12hrs. 24hrs. lions (billure. millions. millions, lions). 70 deg. F. 71. 1,805. 64 deg. F. 29 200. 2,100. 52 deg. F. 4.65 16.7 50.