Troubleshooting High Bacteria Counts in Farm Milk
Contents
1. A standard part of the assessment of any cleaning regime is to document the as found and as prac ticed conditions The purpose of part 2a is to help you determine if the recommended CIP procedures are being followed correctly Every milking system should have a set of written instructions for the CIP process This should include the recommended cycles with the time temperature and chemical concentration specified for each cycle f these instructions have not been provided by the equipment and chemical consultant this part of the form can be used to provide them Make sure that all personnel are aware of and trained in recommended CIP procedures Different hardware and procedures are usually used for cleaning the milking machine and the bulk milk storage tank Observe one complete cleaning to document the cycles used Record the chemical concentrations and tempera ture of the water returning to the wash sink at the beginning and end of each cycle Obtain the best infor mation available about how often each cycle is applied See figure for a sample of the components of a clean in place system Cleaning cycles can be missed routinely or skipped to save time when things get busy Newer automatic wash ers can record whether cleaning cycles actually occurred and the temperature of each cycle The four cycles used in most cleaning regimens in the U S are described below 1 An initial rinse is performed immediately a2. air drawn into units or wash lines at the wash sink Yes ls the ball removed from the sanitary trap during washing Yes Does more than 5 gallons of water drain from the balance tank after the wash cycle Yes Does the milk pump run continuously during the wash cycle Yes ls there any visible residue on system components Describe Location Color Texture Acid Soluble Detergent soluble Chlorine soluble Yes Is the system shock treated If yes how often Note shock treatment dates on bulk tank culture record Yes Do any system components fail to drain after the CIP procedure If yes indicate which Yes Are any valves actuated manually before or during the CIP procedure If yes indicate valve on the system sketch Milk temperature Entering bulk tank At end of milking At pickup top of tank At bottom of tank Premilking sanitize Prewash rinse Detergent wash Acid rinse ther Start temp End temp Cycle time Product used Label concentration Label temperature Concentration used Other measurements PH alkalinity etc Guidelines Follow label instructions for time temperature and concentration 43 54 C 100 130 F Follow label instructions 6 10 min typical 49 77 C 120 170 F Follow label instructions 2 min typical 32 43 C 90 1 10 F Part 2b CIP system design Sketch the milking m
3. s u 295 2 82 Aq 8 5 uin Usdo o lul Are 5 10 3 pue aul 40399 UI re o lul WOJ BdURISIP 9AL7 8 q 4032 0fu aw u do 4o lul are eulsq 15 xtension Authors Douglas J Reinemann is an associate professor in the Department of Biological Systems Engineering at the University of VVisconsin Madison Graeme Mein is a visiting professor in the Department of Dairy Science at the University of Wisconsin Madison David R Bray is a professor of dairy science at the University of Florida David Reid is a practicing veteri narian at the Rocky Ridge Veterinary Service in Hazel Green Wisconsin Jenks Britt is a clinical associate professor of veterinary medicine at the University of VVisconsin Madison Issued in furtherance of Cooperative Extension work Acts of May 8 and June 30 1914 in cooperation with the U S Department of Agriculture University of Wisconsin Extension Cooperative Extension University of Wisconsin Extension provides equal opportunities in employment and programming including Title IX and ADA requirements If you need this information in an alter native format contact the Office of Equal Opportunity and Diversity Programs or call Extension Publishing at 608 262 2655 1998 by the Board of Regents of the Univ
4. AZ USA Peebles R W and Reinemann 1995 Control Strategies to Reduce the Vacuum Pump Capacity Required for Cleaning Milking Systems Paper No 953274 Written for presentation at the 1995 inter national meeting sponsored by the American Society of Agricultural Engineers June 18 23 1995 Chicago Illinois Reinemann D J 1995 System Design and Performance Testing for Cleaning Milking Systems Proc Designing a Modern Milking Center Northeast Regional Agricultural Engineering Service National Conference Rochester New York Nov 29 Dec I 1995 Reinemann D J and R W Peebles 1994 Flow Dynamics in Milking Parlor Clean In Place Systems ASAE Paper No 943567 Presented at the interna tional winter meeting of the American Society of Agricultural Engineers Atlanta Georgia December 13 16 1994 Reinemann D J and J M Book 1994 Airflow Requirements Design Parameters and Troubleshooting for Cleaning Milking Systems Proc ASAF NMC Dairy Housing Conference 3 January 4 Feb 1994 Orlando Florida USA Troubleshooting high bacteria counts in farm milk General information Operator Phone Date Address Equipment Dealer Phone Chemical supplier Phone Prioritized recommendations System sketch Part la Bulk tank cultures can be used to diagnose equip ment cleaning and sanitation problems 2 bacterial incubation in the milk handling system d
5. primarily due to poor pre milking hygiene equipment cleaning and sanitation problems mastitis organisms or incubation of bacteria in the milk handling system This information is invaluable to the dairy producer and processor The recommended tests include e Standard Plate Count SPC The Standard Plate Count is the number of colony forming units in one ml of milk that is plated and incubated for 48 hours at 32 C 90 F The SPC should be less than 5000 if cow and equipment sanitation is good and cooling is adequate An SPC of less than 1000 indi cates excellence in all of these areas Most industry standards require an SPC of less than 50 000 ml with 100 000 ml as the federal maximum e Lab Pasteurized Count LPC The Lab Pasteurized Count is the number of bacteria per ml of milk that survive laboratory pasteurization at 62 8 C 143 F for 30 minutes This procedure kills the usual mastitis causing bacteria leaving only those organisms from the environment that can survive elevated temperatures These types of organisms will grow and multiply in the milk han dling equipment if cleaning and sanitation proce dures are inadequate The LPC should be below 200 ml if equipment cleaning and sanitation are good A LPC below 10 ml indicates excellent equip ment hygiene e Coliform Coli Soil transported from teats and udders into the milking machine is a major source of coliform bacteria in bulk tank milk The Coli count thus prov
6. should also be indicated on the product label 3 An acid rinse cycle may be performed to remove mineral deposits left by milk and hard water The low pH environment created by the acid rinse also inhibits growth of bacteria when the milking equip ment is not in use The temperature of this rinse is typically 38 C to 49 C 100 F to 120 F but may be a cold rinse depending on the product used The product label should specify the recommended concentration and temperature 4 A sanitizing cycle is performed immediately before milking usually with a chlorine based prod uct This kills any bacteria in the milking system that have survived the cleaning process Recommended temperatures for this cycle range from 35 C to 43 C 95 F to 10 F and should be noted on the product label It is the chemical consultant s responsibility based on the water volume and results of water quality tests to prescribe the amount of chemical and temperature to use for each cycle The chemical consultant should be trained and equipped to perform water quality tests measure water temperatures and volumes and deter mine if the appropriate chemicals are being used Clean by hand the exterior surfaces of milking units and any parts of the milking machine that may contact milk and are not part of the CIP circuit Do not use detergents designed for circulation cleaning when you hand clean Shock treatment Some systems use shock treat ments per
7. A3705 Troubleshooting high bacteria counts in farm milk Douglas J Reinemann Graeme A Mein David R Bray David Reid Jenks S Britt Sources of bacterial contamination in raw milk Bacteria in raw milk comes from two main sources 1 organisms transported from the environment into the milking machine and 2 mastitis organisms from within the udder Bacteria deposited in the milking and milk handling equipment multiplies and becomes a major source of contamination if the equipment is not cleaned and sani tized properly You can clean milk handling equipment effectively by using a combination of chemical thermal and physical processes Improper cleaning can result from a failure in any one of these processes Bacterial growth also occurs during milking and becomes an increasing concern as the length of milking time increases The procedures described in this publication are designed to help dairy producers and service personnel identify sources of and eliminate high bacteria count problems in raw milk The methods presented here deal primarily with diagnosing problems relating to pre milk ing cow sanitation and milking equipment cleaning and incubation Methods for diagnosis and treatment of mastitis problems are covered in detail in other publications The form that begins on page 9 may be used as an aid in diagnosis and problem solving It is not intended that you conduct the entire procedure outlined in the form whe
8. achine CIP system on page I Measure the length and diameter of all lines and indicate the location of air injector s Type of system Parlor Round the barn Number of units Claw type Shell and liner type Milk meters or weigh jar type Other equipment Automatic washer type Washline diameter s Automatic washer type Air injector type s Milk wash valve type Ul paddle l butterfly plug Y N Restrictors on jetters or jetter hoses Hole sizes Y N Restrictors on wash lines Hole size Date of last liner change How often are liners changed Date of last change of hoses and other rubber parts Other CIP system characteristics Water quantity and quality Water hardness Water heater Temperature Capacity Water iron content Tank Y N Isa water softener installed Tank 2 Y N ls water softener charged Tank 3 Other water test results Wash sink Determine the minimum water volume required per wash cycle for proper flow dynamics in air injected milking systems Use this estimate to size wash sinks in new systems or to check if the actual water used per cycle is higher or lower than the minimum requirement The requirement for milk meters wash vat and precoolers are approximate and may vary with different component designs If air injection is not used multiply the total gallons for the milkline by 3 If weigh jars are used mult
9. ceiver If the close time is reduced to the minimum value available on the controller and flooding still occurs the capacity of the milk pump may need to be increased Many par lors have an additional pipe to supply water to the milkline in addition to that supplied by the milking units The water flow through these pipes should be restricted in most applications to avoid flooding the system Independent control of water and airflow is required to achieve proper slug velocity and water draw rates 4 Final vacuum recorder testing and unit flow tests After the system has been adjusted accord ing to steps to 3 repeat vacuum recorder testing of slug flow Check the vacuum drop at the beginning end and other critical locations in the milkline Perform a fine adjustment of the air injector at this time The air injector should close just before the slug hits the receiver jar If the air injector remains open after the main slug reaches the receiver excessive water may be carried through the sani tary trap After fine adjustment of the air injector recheck unit flow at critical locations including the first last and middle units on both sides of the par lor and on any units with visible buildup Sequenced air injection Air injection is not required to clean most commercial milking units If these compo nents are not present air injection should be used only on the milkline as shown in figure 2 If air injection is supplied to both
10. ems and milking parlors The usual result is a flooded system Some symptoms of improper air injector location and or timing occur when e the system traps out the ball valve in the sani tary trap shuts off system vacuum during one or more wash cycles e air is drawn into the system at the wash sink When air is drawn into water draw lines or milking units at the wash sink the system has an uncontrolled point of air injection e the milk pump never shuts off during the cleaning cycle and e a large volume of water drains from the distribu tion tank when the vacuum pump is shut off after cleaning If these initial tests indicate that a flow problem may exist you should perform a complete flow evaluation Do not make any changes to the CIP system such as changing air injector timing or changing any hardware without the proper test equipment to properly assess their effects A qualified service person with appropriate test equipment and training should be consulted for a complete flow analysis see parts 3 4 and 5 The instal lation and commissioning of every milking system should include installation of the equipment and adjust ment of the controls to circulate solutions properly throughout the milking system A complete CIP flow analysis should be conducted whenever e anew system is installed e a change is made to an existing system or e milk quality tests indicate a cleaning problem and the recommended CIP pr
11. ersity of Wisconsin System doing business as the division of Cooperative Extension of the University of Wisconsin Extension Send inquiries about copyright permission to Director Cooperative Extension Publishing 201 Hiram Smith Hall 1545 Observatory Dr Madison VVI 53706 You can obtain copies of this publication from your VVisconsin county Extension office or from Cooperative Extension Publications Room 170 630 W Mifflin Street Madison WI 53703 608 262 3346 Before publicizing please check on this publi cation s availability To see more Cooperative Extension publications visit our web site http www uwex edu ces pubs Troubleshooting High Bacteria Counts in Farm Milk A3705 1 4 99 3M 150
12. feet apart for an accurate measurement Vacuum drop A rapid vacuum drop is meas ured when the slug passes the test points The vacuum drop across a slug is a measure of the mechanical cleaning action produced The rec ommended range of vacuum drop across the slug is given in table The vacuum drop should be near the maximum of the range at the begin ning of slug travel This vacuum drop across the slug will decrease slowly as it travels through the line due to slug decay and air entrainment Inadequate vacuum drop across the slug indi cates that the slug is very short and or that Table Recommended range of vacuum drop across the slug Milkline diameter Vacuum drop 48 mm 2 in 5 3 to II in Hg 18 38 kPa 60 mm 2 5 in 4 4 to 9 5 in Hg 15 32 kPa 73 mm 3 in 3 8 to 8 6 in Hg 13 28 kPa 98 mm 4 in 3 2 to 7 1 in Hg 11 24 kPa excessive air is passing through the slug A slow rate of vacuum drop indicates that the slug is moving slowly usually because of excessive water in the pipeline or an excessively leaky milk wash valve 3 Set air injector closed off time The amount of water drawn in during each cycle is determined by the amount of time the air injector is closed or off If the sanitary trap is flooding or excessive water is being transferred through the trap reduce the closed time The closed time should be adjusted so the size of the slug reaching the receiver is just sufficient to wash the re
13. fter milking to remove milk that remains in the system The temperature of this rinse should be between 100 F and 130 F The upper limit has been chosen in the belief that proteins may be baked on to surfaces at temperatures in excess of 140 F The lower limit is set above the melting point of butter fat to ensure that fats will be removed and not redeposited A benefit of increasing the rinse tem perature is that it reduces the temperature drop during the subsequent detergent wash cycle If dropping temperatures during the detergent cycle are a problem consider increasing the rinse tem perature to the upper end of this limit Do not recirculate water used in the initial rinse Figure Example of milking parlor CIP system Wash manifold Air injector r Receiver VVash sink Milkline 2 A detergent wash cycle usually containing a chlorinated alkaline detergent removes organic soils such as milkfat and proteins Consult the label instructions to assess whether as found practices fall within these recommendations Most detergents work at a temperature range between 43 C and 77 C 1 10 F and 70 F The range should be speci fied on the label If organic film is present consider raising the temperature to the upper limit of this range Cleaning effectiveness improves as the tem perature goes up You many need to adjust deter gent concentrations to account for water hardness this information
14. ides an indication of both the effec tiveness of cow preparation procedures during milking and the cleanliness of the cows environ ment Coliform counts between 100 ml and 1000 ml are generally an indication of poor milking hygiene Coliforms will also incubate in residual films left on milk contact surfaces Coliform counts in excess of 1000 suggest that bacteria have incu bated in milk handling equipment A Coli count less than 100 ml of milk is considered acceptable for raw milk for pasteurization In states where raw milk may be sold to consumers Coliform count must be less than 10 ml Coli counts less than 10 indicate excellence in both pre milking hygiene and equipment sanitation e Somatic Cell Count SCC Somatic Cell Count is a routine test of the milking herd s milk quality and udder health High bacteria counts may result when certain types of mastitis organisms such as Strep ag or Step uberis are present in the herd A complete bulk tank culture with species differentia tion should be performed periodically to determine the type of mastitis organisms present in the milk Be particularly careful when you collect and store sam ples for these tests Be sure that samples are not con taminated Store them at temperatures below 4 C 40 F or freeze them until processed Do not make a diagnosis based on a single test take a series of at least three If you are concerned about producing quality milk per form this ent
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16. iodically to reduce bacteria counts This pro cedure is commonly performed using a higher than usual concentration of chemicals Shock treatments shorten the life of equipment They are also expensive and dangerous and do not correct the source of the problem Shock treatments should not be required if the cleaning system is operating properly Residual films Cleaning failures usually result in a buildup of residual film you can see on some parts of the milk harvesting or storage equipment Some of these films have a characteristic appearance that can help you determine why the cleaning failure occurred There are two broad categories of residual films organic films such as fat and protein and 2 inorganic films such as hard vvater minerals iron and silica Discoloration may also occur due to corrosion and or pitting of surfaces Protein films can appear as a brovvn ish slime when wet Mineral films usually have a rough porous texture and are invisible when wet Organic films are generally alkaline soluble while inorganic films are generally soluble in acid Protein films dissolve in chlorine Films can be diagnosed by scrubbing a small area with concentrated acid and or detergent solutions Drainage Improper drainage is a common source of bacterial contamination and mixing of cleaning solu tions thus reducing the solutions effectiveness All parts of the milking system both sanitary and non sani tary should drain when the
17. ion should travel to the receiver without breaking Measure the distance that the slug must travel from the point of air injection to the receiver Divide the slug travel distance by the desired slug velocity to determine the air injector open time Slug velocity for optimal mechanical action is between 7 and 10 meters per second 23 and 33 feet per second 2 Check slug velocity and adjust air admission rate Slug velocity should be measured using a vac uum recorder and the air admission rate adjusted to achieve the desired velocity The rate at which air is drawn in through the air injector determines the travel speed of the slug The physical connec tion to the milkline for vacuum measurement is best done with a tee inserted in line with a milk hose near the milk inlet Sections of transparent tubing 10 to 20 feet in length should be used to connect to the recorder Observe these tubes closely and bleed them often to prevent water from reaching the recorder To minimize the risk of water entering the vacuum recorder it is advisable to leave the hoses detached except when a meas urement is being taken Moisture traps will fill with water very quickly and are not recommended The following information can be obtained from these vacuum recordings Slug velocity Slug velocity can be calculated by dividing the slug travel distance between the two measurement points by the time between vacuum drops The tests points should be at least 30
18. iply the milk meter gallons by 4 x Multiplier Gallons Feet of milkline Line diameter 4 in x 0 12 Line diameter 3 in x 0 07 Line diameter 2 5 in x 0 05 Line diameter 2 in x 0 03 Line diameter 1 5 in x 0 02 Feet of wash draw and milk transfer line Line diameter 3 in x 0 34 Line diameter 2 5 in x 0 23 Line diameter 2 in x 0 15 z Line diameter 1 5 in x 0 09 Receiver s Volume gallons x 0 33 Number of milking units x 0 25 Number of milk meters x 0 25 Feet of milk hose Hose diameter 6 in x 0 012 Hose diameter 56 in x 0 016 Number of precoolers Number of wash vats Total gallons Unit flow measurement for milking parlors Measure unit flow at the first middle and last unit on each side of the parlor Also measure any units that appear dirty Unit flow analysis units should have no less than 3 L min with no more than 50 variation between the high est and lowest units Higher flow rate may be required to clean some components such as milk meters or weigh jars Consult manufacturer s recommendations Time of sample Average flow rate L min or Ib min Unit number Restrictor type Water volume refer to sketch and size liters or Ibs min As found After change A
19. ire series of tests weekly on large farms and at least monthly on small farms These tests can help you quickly identify a problem situation before it becomes a crisis and can provide valuable information for assessing the relative performance of different pre milking cow preparation methods and different equip ment cleaning and sanitation regimes Strategic milk sampling Part Ib When routine bulk tank testing indicates that a prob lem exists you can perform more detailed tests to fur ther isolate the source of the problem If the bulk tank analysis in part la indicates that equipment sanitation or incubation is the major source of bacteria proceed with strategic milk sampling to further identify the source Strategic sampling of milk at different times during the milking process will determine if bacterial incubation in the milk handling system is a major source of contamination Strategic sampling of milk in different locations will determine if the location of a cleaning failure and or incubation problem lies in e the milking units milkline and receiver e the milk transfer line including filters and precoolers or e the bulk tank Observation of CIP procedures Part 2a If milk quality testing in part indicates that there may be equipment cleaning problems proceed to part 2b to identify the specific cause Concentrate your observa tions on those parts of the system indicated by strate gic milk sampling
20. never you encounter a high bacteria problem Rather the procedure begins with simple routine test ing which depending upon the results may lead to rec ommendations for more complex and comprehensive testing This publication takes you step by step through the process of filling out the form and provides supplemen tary information about each section You will also find a list of references at the end of this publication for more information Routine bulk tank testing Part la All farms periodically conduct some form of testing for bacterial contamination to assure compliance with national state and local milk plant requirements These tests usually include the Somatic Cell Count SCC Standard Plate Count SPC and may also include the Preliminary Incubation count PI or other tests These tests provide an overall measure of milk quality but have little diagnostic value in locating the source of bacterial contamination We recommend that you per form additional tests to aid in diagnosing the cause of high bacteria counts Routine bulk tank evaluation can be used to assess the types and levels of mastitis in a herd the practices of the milkers and the effectiveness of equipment cleaning and sanitation Methods for routine bulk tank culture analysis have been presented by Guterbach and Blackmer 1984 and have been adopted by a number of progressive milk processors These techniques indicate whether high bac terial counts are
21. o further diagnose the source of the problem Take milk samples from the receiver s transfer line s and bulk tank after the first group of cows is milked one cow for each milking unit and after every four hours of milking or since the system has been washed taking a final sample at the end of milking or before the next wash cycle Record the results of these tests in the following table e Elevated counts in the receiver samples at the begin ning of milking likely indicate a cleaning problem in the milking units milk meters milkline or hoses If this situation exists perform the CIP flow analysis e Elevated counts in transfer lines but not in receivers after the first group of cows indicates cleaning fail ure in the transfer line and equipment between the receiver and bulk tank such as plate coolers and milk filters A continual rise in counts during milking indicates bacterial incubation as the likely cause Solutions to this problem may include replacing rubber goods washing the system more thoroughly and frequently changing the milk filter SPC After first group of cows After 4 hours After 8 hours End of milking Time of sample Receiver Receiver 2 Transfer line Transfer line 2 Bulk tank Bulk tank 2 CIP procedures observations Part 2a Yes Does the sanitary trap valve close trap out during the CIP procedure Yes
22. ocedures are being fol lowed Water quantity and quality Part 3 Air being drawn into the milking units or draw lines at the wash sink may be caused by flooding of the milking system usually a result of improper air injection or because of inadequate water volume The minimum water volume required for proper flow dynamics can be estimated using the table in Part 3 This table can be used to determine if the minimum water volume is available for each wash cycle and to determine if water and chemical costs can be reduced by improving the configuration or flow dynamics of the CIP system Chemical cleaning concentration may need to be adjusted for hard water Record the water hardness to determine the appropriate concentrations Unit flow in milking parlors Part 4 A common problem in milking parlor systems is uneven distribution of water to the milking units Visual indica tors of low flow in a milking unit jetter combination include reverse flow in jetter hoses and e a milking unit claw that never floods during the cleaning cycle The flow rate through milking units and milk meters can be measured using the method illustrated in figure 1 Document the flow in the first last and middle units and any units that appear dirty Ideally flow should be uniform through all milking units in the parlor Field studies indicate that 3 L min 0 8 gal lons min is sufficient to clean most milking units While many units clean a
23. ons are not adequately distributed to all parts of the milking system If the cleaning solution does not reach surfaces that come into contact with milk the desired chemical and thermal actions cannot take place Part 2b provides a way to conduct an initial assessment of the water and airflow dynamics of a milking CIP system These obser vations and measurements can be performed without special test equipment vacuum recorder vacuum gauge and airflow meter Conduct these observations if milk quality tests indicate a cleaning problem in the milking machine but all cleaning cycles appear to function properly The first step in assessing flow dynamics is to under stand the intended flow circuit A sketch of the CIP sys tem will aid in understanding the flow circuit and docu ment conditions for future reference and consultation with equipment service personnel The sketch should indicate the diameter and length of all lines and loca tions of critical components such as receiver s wash sink s air injector s wash valve s and any other equipment that is cleaned or used for cleaning Document the location of any manual or automatic valves that may be operated before or during the wash cycle and check whether air is being drawn in at the wash sink Also check the timing of the air injector Flow problems commonly result from improper air injector location and or timing cycles This can be a problem in round the barn RTB highline syst
24. system is shut off Inspect the milking system for any pipes hoses fittings and equipment that do not drain when the system is shut off Other parts of the system The non sanitary parts of the milking machine may also be a source of bacteri al contamination If milk quality tests indicate an equip ment cleaning and sanitation problem in the milking machine and the source cannot be found in the milking units hoses milkline or receiver perform a visual inspection of air lines and ancillary equipment such as backflush systems These non sanitary parts of the sys tem should be cleaned periodically as part of the sys tem s routine maintenance The seals and gaskets and all rubber goods should be changed at least annually Aged rubber becomes porous and is very difficult to clean Milk temperature The temperature of the milk at various points in the system will help determine if the cooling system is operating correctly Inadequate cool ing will increase bacteria counts by allowing a better environment for bacteria growth during storage Milk should be cooled to 4 4 C 40 F or below within 30 minutes of milking and held between 0 and 4 4 C 32 and 40 F until pasteurized If milk is not mixed adequately in the storage tank temperature stratifica tion may occur and reduce the effective cooling of the upper layers of milk Observation of CIP flow dynamics Part 2b A cleaning failure will take place if cleaning soluti
25. t flow rates below this value the risk of cleaning failure is increased Milk meters and weigh jars may require water flow rates of 4 5 to 6 L min 1 2 to 1 6 gallons min to clean effectively Install flow restrictors at each jetter to balance the flow Changing the flow rate to the milking units or milk meters may require an adjustment to the air injector timing and or water volume required per cycle Do not change either of these without contacting the service person and or chemical consultant Milkline slug flow dynamics Part 5 Proper test equipment is required to properly diagnose CIP circulation problems Only a qualified service tech nician with the proper test equipment should attempt to set up and troubleshoot CIP flow dynamics A vacuum recording device commonly used to evaluate milking performance is an essential piece of test equip ment required to assess air injected slug flow during cleaning More detail on diagnostic methods using a vac uum recorder for CIP analysis is given in the refer ences The following procedure has been developed to set air injector timing and diagnose faults 1 Set air injector open time The air injector open time is a relatively easy number to calculate and should be the first step in setting up an optimal cleaning cycle The length of time that the air injec tor is open together with slug velocity determine the travel distance of the slug The slug formed at the point of air inject
26. the milkline and the wash manifold two air injection points should be used with the injec tion sequenced so that both injectors are not open at once Air injection should be used on the jetter line only if difficult to clean components such as weigh jars or some milk meters are present Optimal air injector timing is usually different for wash manifolds than for the milk line Sequenced air injection allows for opti mization of both thus improving cleaning action in the milking system as well as reducing vacuum pump requirements Further details on sequenced air injection are provided in reference 4 Figure 2 Unit flow measurement for milking parlors Wash line Milking unit Test bucket with lid Milk line References Bray D R and J K Shearer 1996 Trouble Shooting a Mastitis Problem Herd University of Florida Cooperative Extension Circular 1164 Guterbach W M and PE Blackmer 984 Veterinary Interpretation of Bulk Tank Milk Veterinary Clinics of North America Large Animal Practice Vol 6 No 2 July 1984 Pp257 268 Muljadi A Reinemann and A C L Wong 1996 Air injected Clean In Place for Milking systems Development of a Study Method and Characterization of Chemical Mechanical and Thermal Factors ASAE paper No 963019 Written for presentation at the 1996 international meeting sponsored by the American Society of Agricultural Engineers July 14 18 1996 Phoenix
27. uring milking 3 inadequate pre milking hygiene and 4 mastitis Good Warning Action needed SPC HHH HH 1000 5000 10 000 100 000 Good Dirty equipment LPC 1 HHH HH 10 50 100 500 1000 Good Dirty cows Incubation Coli m HH H 10 50 100 500 1000 SCC Good Wareng Aetion 55 100 000 500 000 1 000 000 Date Routine milk quality analysis In general e Equipment cleaning and sanitation problems typical ly result in elevated LPC counts e Incubation of bacteria in the milking system cause elevated Coli above 1000 and LPC counts e Inadequate premilking hygiene will result in elevated Coli counts typically 100 to 1000 e f both SCC and SPC are high mastitis organisms may be the cause of high bacteria counts Take composite milk samples from the bulk tank at the time the milk is shipped from the farm Perform the tests indicated above on a routine basis a minimum of monthly on small farms and weekly on large farms and more often if a problem situation exists A minimum of three tests is needed to make a diagnosis Record the culture results and test dates below SPC Standard Plate Count LPC Lab Pasteurized Count Coli Coliform Count SCC Somatic Cell Count Part Ib Strategic sampling If routine bulk tank analysis indicates that equipment cleaning and sanitation may be a problem it is desirable t
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