per 100 ml in the raw water supply can be toler- 

 ated. Coliform densities above this level may re- 

 quire special treatments. 



It should be kept in mind that negative test 

 results cannot be considered as an assurance of a 

 continuously safe supply unless the results of sani- 

 tary surveys and subsequent negative tests support 

 such a position. 



In addition to limitations for coliform orga- 

 nisms, water used for dairy sanitation should con- 

 tain no more than 20 organisms of all other types 

 per milliliter and no more than 5 proteolytic and/ 

 or lipolytic organisms per milliliter {111).^ 



Determination of quality 



Monitoring and Periodic Checks 



Water for farmstead use should be sampled and 

 examined for bacteriological contamination upon 

 completion of the supply system and when the sys- 

 tem is repaired or changed. Samples should be 

 taken also to determine the physical and chemical 

 characteristics of the supply at the time of initial 

 use of the system. Bacteriological analysis should 

 include testing for important groups of nonpatho- 

 genic bacteria in addition to usual coliform deter- 

 minations. 



Samples of water for farmstead use should be 

 taken periodically during the year and analyzed 

 for bacteriological, physical, and chemical charac- 

 teristics. If there is any likelihood that composi- 

 tion has changed, more frequent sampling may 

 be necessary if the source is known to be of vari- 

 able quality. During a temporary shortage when 

 water is hauled to a dairy farm producing milk 

 under a sanitary code based on the USPHS grade 

 A Pasteurized Milk Ordinance (176), it is man- 

 datory that a sample of such water be taken each 

 month at the point of use and submitted to a 

 laboratory for bateriological examination. When 

 the quality is such that treatment is necessary to 

 meet USPHS standards described above, the farm 

 operator or his representative should make fre- 

 quent tests (at least weekly) to determine that the 

 equipment is operating properly. 



^ Standard methods for the examination of dairy 

 products. 1960. 11th ed. APHA, Inc., N.Y. Hammer, 

 B. W., and F. J. Babel, 1957. And, Dairy bacteriology, 

 4th ed. John Wiley & Sons. pp. 15-16. 



Procedures for Analysis 



Procedures used in the determination of water 

 quality factors are, for the most part, standard 

 methods applicable in the examination of water 

 regardless of its source or intended use. In view of 

 this fact, methods for sampling and analysis are 

 found in the section on Sampling and Analytical 

 Procedures of this report. 



Specific recommendations 



Discussion of Limiting Criteria 



Water for use by the human farm population, 

 for washing and preparation of raw farm products 

 for marketing, and for dairy sanitation should be 

 potable as a minimum requirement. Also, in de- 

 veloping water sources, attention should be given 

 to assure that the supply used does not contain 

 microorganisms or chemicals which can cause 

 product deterioration or adversely affect sanita- 

 tion procedures. 



Farms using multiple sources of water should 

 keep supplies separate and have each analyzed 

 with reference to the quality criteria previously 

 listed. Withdrawal from each of the several sources 

 should be planned and adjustments made in sanita- 

 tion and treatments based on the composition of 

 that water. 



Many species of bacteria are capable of estab- 

 lishing cultures in unclean or corroded pipes. 

 Samples of water for analysis should be taken at 

 the outlet as well as at the source to determine 

 .the presence of any microbial buildup in piping 

 systems. Pipes may become perforated by corro- 

 sion, or leaks may develop at pipe joints permitting 

 polluted water to be drawn into the normal supply 

 system. 



Evaluation of Recommendations — 

 Needs and Their Achievement 



The history of American agriculture indicates 

 that a suitable water supply for general farm use 

 can be obtained usually with little trouble if at- 

 tention is paid to developing proper sources. The 

 use of low-quality water can normally be traced 

 to lack of knowledge as to what constitutes an 

 acceptable supply, rather than any inability to 

 correct known, undesirable conditions. 



Certain nonpathogenic bacteria have the ability 

 to withstand high chlorine residuals. When such 

 bacteria are present, they may be controlled by 

 alternative methods. 



126 



