available every day throughout the year. Failure of 

 the supply, such as during a drought or freezing 

 weather, has serious consequences in milkhouse 

 sanitation. Sanitary care of milk-handling equip- 

 ment is an everyday must and when water is scarce, 

 sanitation suffers. 



2. Clear, colorless, good taste, relatively soft. 

 — Soft water requires less detergent and gives bet- 

 ter cleaning. Dirty water results in dirty utensils. 

 Milk is susceptible to off flavors; poor tasting water 

 does not help. 



3. Free from harmful bacteria, yeast, and 

 molds. — Unsafe water may cause disease. Some 

 bacteria cause rancid flavors in milk while others 

 can cause bitter, fruity, and/or other unpleasant 

 flavors. Yeasts and molds also contribute to flavor 

 defects of milk products. 



4. Noncorrosive water. — Corrosion shortens 

 the life of piping and water heaters. Copper and 

 iron dissolved from piping by acid water may 

 cause oxidized flavors in milk products. 



5. Nonscale-forming water. — Scale may clog 

 pipes, faucets, boilers, and water heaters {111). 



General problem areas 



Limitations of On-Farm Treatment: The raw 



water supply available to farmers must be of such 

 quality that it can be used in the raw state or be 

 made acceptable for farmstead use with minimum 

 treatment such as disinfection, filtration, and/or 

 softening. Economic considerations alone will 

 prohibit use of raw supplies that require extensive 

 treatment to make them suitable for farmstead 

 uses. 



Many surface waters have turbidities in excess 

 of what can be used effectively in home or farm 

 operations. The coagulation, settling, and filtration 

 systems used in municipal water plants are imprac- 

 tical for small-scale use. Pressure sand filters or 

 diatomaceous earth filters are not recommended 

 for farm use when turbidities exceed 20 units and 

 are not effective at this level if the supply has ex- 

 cessive bacteria or organic materials present. 

 Small in-line filters with porous rigid media or 

 composition disc filters are used successfully for 

 small systems but are not successful if high capac- 

 ity is desired or if turbidities exceed 5 to 10 units 

 {89). 



Control of water hardness is desirable for do- 

 mestic uses and is essential for proper sanitary 

 control of milk contact surfaces. However, except 

 for supplies containing in excess of 100 to 150 



mg/1 total hardness, cleaning compounds can be 

 formulated which provide adequate softening. 

 Such water may produce waterstone in heaters or 

 milk cooling tanks when used for ice-bank cooling 

 or for water-cooled compressors. 



For farm supplies exceeding 100 mg/1 total 

 hardness, control can be effective using cation 

 exchange processes. When properly operated, ion 

 exchange systems are quite inexpensive and gen- 

 erally satisfactory. However, unless the equip- 

 ment is properly maintained and operated the 

 ion exchange capacity of the system will be de- 

 pleted and sanitation will suffer if the resultant 

 untreated hard water is used to prepare cleaning 

 solutions. At the same time, temporary hardness 

 chemicals (bicarbonates) will precipitate to cause 

 continuing heat transfer problems in water heaters 

 and milk coolers. 



Tests for total hardness do not indicate the spe- 

 cific type of hardness and, consequently, the farm 

 water supply may contain ions other than calcium 

 and magnesium. These may be treated with ap- 

 proximately the same efficiency if specific methods 

 are applied but are not removed by simple systems 

 designed for calcium and magnesium alone. 



Ion exchange softeners will filter some particles 

 from water but are not intended for that purpose. 

 Thus, if the supply also has a sediment problem, 

 filters should be installed ahead of the softener, 

 since sediment in the exchange bed will greatly 

 reduce the capacity of the softener. Water with a 

 high iron concentration will form a precipitate 

 which also will interfere with softener operation. 



Sources of Supply Limitations: Water for farm 

 use can be obtained from three general sources of 

 supply. These include: (1) Precipitation (rain, 

 snow, etc.); (2) surface water (exposed bodies of 

 fresh water); and (3) ground water (water from 

 a saturated zone in the earth) . 



Atomospheric water is likely to be the most pure 

 of available supplies. When impounded in suitable 

 cisterns, it is a source of soft, high-quality, and 

 inexpensive water which may not need further 

 treatment for many farm uses. When used for 

 drinking purposes or for final rinsing of milk con- 

 tact surfaces, it should be treated to destroy any 

 pathogenic or psychrophilic bacteria. 



Surface water may be defined as atmospheric 

 water which is not collected in cistern^, but rather 

 runs off to collect in streams, ponds or lakes, 

 swamps, etc. Such waters will collect all types of 

 bacteria and organic and inorganic materials as 

 they flow over (or through) the topsoil. All such 

 supplies should be treated by filtration and disin- 



121 



