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CFSAN/Office of Compliance
March 2, 2004
Type:
Scale Range: At least 7°C (12°F) below and 7°C (12°F) above the pasteurization temperature at which the operating thermometer is used, with extensions of the scale on either side permitted and protected against damage at 149°C (300°F).
Temperature Represented by Smallest Scale Division: 0.1°C (0.2°F).
Number of Degrees per 25 Millimeters (1 inch) of Scale: Not more than four (4) Celsius degrees or not more than six (6) Fahrenheit degrees.
Accuracy: Within ± 0.1°C (± 0.2°F), throughout specified scale range. The accuracy shall be checked against a thermometer, which has been tested by the National Institute of Standards and Technology (NIST).
Bulb: Corning normal or equally suitable thermometric glass.
Case: Suitable to provide protection during transit and periods when not in use.
Digital Test Thermometer: Hand-held; high accuracy digital thermometer; and battery or AC line powered. Calibration is protected from unauthorized changes.
Range: -18°C to 149°C (0°F to 300°F); Temperature represented by smallest scale division, 0.01°C or °F and digital display.
Accuracy: System accuracy of: ± 0.056°C (± 0.100°F); Probe accuracy of: ± 0.05°C (± 0.09°F); Repeatability of ± 0.005°C (± 0.009°F); Three (3) month stability: ± 0.025°C (± 0.045°F). Thermometer accuracy from 0°C to 150°C (32°F to 302°F): ± 0.05°C (± 0.09°F). Calibration uncertainty: ± 0.0047°C (± 0.00846°F). The accuracy shall be checked against a thermometer, which has been tested by NIST. A certificate of calibration shall be maintained with the unit.
Self-Diagnostic Circuitry: Circuitry shall provide constant monitoring of all sensing, input and conditioning circuits. The diagnostic circuitry should be capable of identifying the probe and its calibration information. Without a correct connection of the probe, the display shall alert the operator and no temperature will be displayed.
Electromagnetic Compatibility: Shall be documented for these devices for their intended use and available to the Regulatory Agency. Units to be used in the "field" shall have been tested for heavy industrial standards, as specified in the European Electromagnetic Compatibility Directive.
Immersion: Minimum immersion point shall be marked on the probe. During control tests, the probes shall be immersed to equal depths in a water or oil bath.
Case: Suitable to provide protection during transit and periods when not in use.
Type: Pocket type.
Scale Range: 1°C (30°F) to 100°C (212°F), with extensions of the scale on either side permitted. Protected against damage at 105°C (220°F).
Temperature Represented by Smallest Scale Division: 1°C (2°F).
Accuracy: Within ± 1°C (± 2°F), throughout the specified scale range. Checked periodically against a known accurate thermometer.
In the case of mercury actuated general-purpose thermometers, the following additional specifications shall apply:
Magnification of Mercury Column: To apparent width of not less than 1.6 millimeter (0.0625 inch).
Number of Degrees per Inch of Scale: Not more than twenty-nine (29) Celsius degrees or not more than fifty-two (52) Fahrenheit degrees.
Case: Metal, provided with a fountain pen clip.
Bulb: Corning normal or equally suitable thermometric glass.
Type: Manual or automatic.
Conductivity: Capable of detecting change produced by the addition of ten (10) pm of sodium chloride, in water of 100 ppm of hardness.
Electrodes: Standard.
Automatic Instruments: Electric clock, time divisions not over 0.2 of a second.
Type: Open face, indicating fractional seconds.
Accuracy: Accurate to 0.2 of a second.
Hands: Sweep hand, if applicable, one complete turn every sixty (60) seconds or less.
Scale: Divisions of not over 0.2 of a second.
Crown: Depression of crown or push button starts, stops and resets to zero.
Equipment and field tests to be performed by the Regulatory Agency are listed and suitably referenced below. The results of tests shall be recorded on suitable forms and filed, as the Regulatory Agency shall direct. (Refer to Appendix M.)
Reference: Item 16p (A), (B), (C) and (E)
Application: To all indicating thermometers used for the measurement of milk or milk product temperature during pasteurization or aseptic processing, including airspace thermometers.
Frequency: Upon installation; at least once each three (3) months thereafter; whenever the thermometer has been replaced or the regulatory seal on a digital sensor or a digital control box has been broken.
Criteria: Within ± 0.25°C (± 0.5°F) for pasteurization and aseptic processing thermometers and ± 0.5°C (± 1°F) for airspace thermometers, in a specified scale range. Provided, that on batch pasteurizers used solely for thirty (30) minute pasteurization of milk or milk products at temperatures above 71°C (160°F), indicating thermometers shall be accurate to within ± 0.5°C (± 1°F).
Apparatus:
Method: Both thermometers exposed to water, oil or other suitable media of uniform temperature. Indicating thermometer reading is compared to the reading of the test thermometer.
Procedure:
Corrective Action: Do not run the test if the mercury column has been split or capillary tube is broken. The thermometer should be returned to the factory for repair. When the indicating thermometer differs from the test thermometer by more than 0.25°C (0.5°F) and the airspace thermometer by more than 0.5°C (1°F), the indicating thermometer should be adjusted to agree with the test thermometer. Retest the thermometer after adjustment.
Reference: Item 16p (A), (B), (C) and (E)
Application: To all recording and recorder-controller thermometers controllers used to record milk or milk product temperatures during pasteurization or aseptic processing.
Frequency: Upon installation; at least once each three (3) months thereafter; whenever the recording pen-arm setting requires frequent adjustment; when the sensing element has been replaced; or when a regulatory seal has been broken.
Criteria: Within ± 0.5°C (± 1°F), in specified scale range. Provided, that on batch pasteurizers used solely for thirty (30) minute pasteurization of milk or milk products at temperatures above 71°C (160°F), the recording thermometers shall be accurate to within ± 1°C (± 2° F), between 71°C (160° F) and 77°C (170°F).
Apparatus:
NOTE: When this Test is performed on recorder-controllers used with HHST pasteurization or aseptic processing systems that operate at or above the boiling point of water, an oil or other suitable media bath shall be substituted for the processing (operating) temperature water mentioned in Procedures 1, 4, 5, 6, and 7 as well as the boiling water mentioned in Procedures 2, 3 and 5. The temperature of the oil bath that is used in place of the boiling water shall be above the normal operating range but below the highest temperature division on the chart.
Method: The testing of a recording thermometer for temperature accuracy involves the determination of whether or not the temperature pen-arm will return to within 0.5°C (1°F), or 1°C (2°F) as provided in the Criteria above, of its previous setting, after exposure to high heat and melting ice.
Procedure:
Corrective Action: If the recording thermometer pen does not return to ± 0.5°C (± 1°F), or ± 1°C (± 2°F) as provided above, of indicating thermometer reading at Procedures 4 and 6, the recording thermometer shall be repaired or replaced as necessary.
Reference: Item 16p (A), (B), (C) and (E)
Application: To all recording and recorder-controller thermometers used to record the time of pasteurization or aseptic processing, including those used to record flow rates in magnetic flow meter based timing systems.
Frequency: Upon installation; at least once each three (3) months thereafter; or whenever the seal of a programmable recorder-controller has been broken.
Criteria: The recorded time of pasteurization or aseptic processing shall not exceed the true elapsed time.
Apparatus:
Method: Comparison of the recorded time over a period of not less than thirty (30) minutes with a watch of known accuracy. For recorders utilizing electric clocks, check the cycle on the faceplate of the clock with a known cycle and observe that the clock is in operating condition.
Procedure:
Corrective Action: If recorded time is incorrect, the clock should be adjusted or repaired.
Reference: Item 16p (A), (B), (C) and (E)
Application: To all recording and recorder-controller thermometers used to record milk or milk product temperatures during pasteurization or aseptic processing.
Frequency: Upon installation and at least once each three (3) months by the Regulatory Agency, or HACCP qualified industry person, acceptable to the Regulatory Agency, qualified under Item 16p(E)2; and daily by the milk plant operator.
Criteria: The recording thermometer and recorder-controller thermometer shall not read higher than the indicating thermometer.
Apparatus: No supplementary materials required.
Method: This test requires only that the reading of the recording thermometer or the recorder-controller thermometer be compared with the indicating thermometer at a time when both are exposed to milk or milk product at a stabilized pasteurization or aseptic processing temperature.
Procedure:
NOTE: This test shall be performed while the pasteurization operating temperatures are within the accurate range for the specific thermometers and charts used.
Corrective Action: If the recording thermometer or recorder-controller thermometer reads higher than the indicating thermometer, the pen or temperature adjusting mechanism shall be adjusted by the operator.
Reference: Item 16p (B), (C) and (E)
Application: Test 5 (parts 1 through 9) does not apply to aseptic processing divert systems, valves or other acceptable controls which may be used in place of a FDD. Parts 1 to 4 and 6 to 8 apply to all FDDs used with continuous-flow pasteurizers. Parts 5 and 9 apply only to FDDs used with HTST pasteurizers.
Frequency: Upon installation; at least once each three (3) months thereafter; or when a regulatory seal has been broken.
Criteria: The FDD shall function correctly in operating situations and shall de-energize the timing pump and all other flow-promoting devices capable of causing flow through the FDD, in the event of malfunction or incorrect assembly.
Apparatus: Suitable tools for the disassembly of the FDD and the sanitary piping.
Method: Observe the valve seat(s) of the FDD for leakage.
Procedure:
Corrective Action: If leakage is noted, the FDD must be dismantled and defective gaskets replaced or other suitable repairs made.
Apparatus: Suitable tools for tightening the packing nut on the stem(s)
Method: Observe the FDD valve stem(s) for ease of movement.
Procedure: When a stem-packing nut is used, tighten it as much as possible. Operate the system at maximum normal operating pressure and place the FDD in forward and diverted-flow several times. Note the freedom of action of the valve stem.
Corrective Action: If the valve action is sluggish, suitable adjustment or repair shall be made. The stem shall move freely in all positions, when the stem-packing nut is fully tightened.
Apparatus: Sanitary fitting wrench
Method: When the FDD is improperly assembled and in diverted-flow (below cut-out temperature), observe the function of the timing pump and all other flow-promoting devices capable of causing flow through the FDD.
Procedure:
Corrective Action: If any flow-promoting device fails to respond as indicated, immediate checks of the device assembly and wiring are required to locate and correct the cause.
NOTE: The test procedure presented in this Section is typical of tests accepted by FDA for various specific types of FDDs. Testing details, which may vary, are provided in individual FDD operator's manuals that have been reviewed by FDA and are specified by part number in FDA's Coded Memoranda (M-b's). In each of these FDA accepted test methods, if the words "metering pump" or "timing pump" are used they shall be understood to mean "timing pump and all other flow-promoting devices, which are capable of causing flow through the FDD".
Apparatus: None
Method: Observe the function of the timing pump and all other flow-promoting devices, which are capable of causing flow through the FDD when the FDD is improperly assembled.
Procedure:
Corrective Action: If any of the flow-promoting devices fail to respond as indicated, an immediate check of the FDD assembly and wiring is required to locate and correct the cause.
Apparatus: None
Method: Observe the response of the system to manual diversion.
Procedure:
Corrective Action: If the above described actions do not occur, or the necessary pressure differential between raw and pasteurized milk or milk product is not maintained, the assembly and wiring of the HTST system must be immediately reviewed and the indicated deficiencies corrected or proper adjustments made.
Apparatus:
Method: Determine the elapsed time between the instant of the activation of the control mechanism at cut-out temperature on declining temperature and the instant the FDD takes the fully diverted-flow position.
Procedure:
Corrective Action: If the response time exceeds one (1) second, immediate corrective action must be taken.
Application: To all dual stem FDDs with a manual forward-flow switch.
Apparatus: None
Method: Determine that the device does not assume a manually induced forward-flow position, while the timing pump or any other flow-promoting device, which is capable of causing flow through the FDD is operating.
Procedure: With the system operating in forward-flow, move the control switch to the "Inspect" position and observe that the following events automatically occur in sequence:
Corrective Action: If the above sequence of events do not occur, either a timer adjustment or wiring change is required.
Application: To all continuous-flow pasteurizer systems in which it is desired to run the timing pump and/or other flow-promoting devices during the CIP cycle without the controls required during product processing.
Criteria: When the mode switch on the FDD is moved from "Process" to "CIP", the FDD shall move immediately to the diverted position. It shall remain in the diverted position for at least ten (10) minutes, with all public health controls required in "Process" mode functioning, before starting its normal cycling in the "CIP" mode. In HTST systems, the booster pump shall be de-energized during the ten (10) minute time delay.
Apparatus: Stopwatch
Method: Determine that the set point on the time delay relay is equal to or greater than ten (10) minutes.
Procedure:
NOTE: The appropriate temperature elements may be placed in a water or oil bath to simulate the normal pasteurization temperature of the holding tube as an alternative to heating the water in the system above the pasteurization temperature.
Corrective Action: If the FDD does not remain in the diverted position for at least ten (10) minutes after the mode switch is moved from "Process" to "CIP", increase the set point on the time delay relay and repeat this test procedure. All public health controls required when the system is in "Process" mode and in diverted-flow must be functional during these ten (10) minutes. If any of the public health controls are not functional during these ten (10) minutes, adjustments or repairs are needed. In HTST systems, if the booster pump runs at any time during the ten (10) minute delay, the booster pump wiring is in need of repair.
Application: The minimum one (1) second delay applies to HTST continuous-flow pasteurizers in which space between the divert and leak-detect valve is not self-draining in the diverted-flow position.
The maximum of five (5) seconds for this delay is not applicable if:
Criteria: The leak-detect valve will be flushed for at least one (1) second and not more that five (5) seconds after the divert valve moves to the forward-flow position and before the leak-detect valve moves to the forward position.
Apparatus: Stop watch
Method: Observe the movement of the divert and leak-detect valves to the forward-flow position and measure the time interval between the movement of the two (2) valves.
Procedure:
Corrective Action: If the elapsed time is less than one (1) second or greater than five (5) seconds, appropriate changes to the system or system controls must be made.
Reference: Item 16p (A) and (E)
Application: To all batch (vat) pasteurizer outlet valves and to all batch (vat) pasteurizer inlet valves, which are not disconnected and removed during holding, cooling and emptying periods.
Frequency: Upon installation; and at least once each three (3) months thereafter.
Criteria: No leakage of milk or milk product past the valve seat in any closed position.
Apparatus: No supplementary materials required.
Method: By observing when the piping is disconnected from the valve outlet whether or not leakage past the valve seat occurs when pressure is exerted against the upstream face of the valve.
Procedure:
NOTE: Care must be taken to avoid contamination of the valves or the piping.
Corrective Action: If leakage past the valve seat should occur in any closed position, the valve plug should be re-ground, gaskets replaced, or any other necessary steps shall be taken to prevent leakage.
Reference: Item 16p (B) and (E)
Application: To all HTST indicating thermometers located on pipelines and used for the determination of milk or milk product temperatures during pasteurization.
Frequency: Upon installation; once each three (3) months thereafter; and whenever the seal on a digital thermometer has been broken.
Criteria: Four (4) seconds under specified conditions.
Apparatus:
Method: By measuring the time required for the reading of the thermometer being tested to increase 7°C (12°F) through a specified temperature range. This range must include the pasteurization temperature. The temperature used in the water bath will depend upon the scale range of the thermometer to be tested.
Procedure:
NOTE: Continuous agitation of the water baths during the performance of Procedures 3, 4 and 5 is required. The elapsed time between the end of Procedure 1 and the beginning of Procedure 3 should not exceed fifteen (15) seconds, unless a constant temperature bath is used to prevent the hot water bath from cooling significantly.
For Example: For a thermometer used at pasteurization temperature set points of 71.7°C (161°F) and 74.4°C (166°F), a water bath at a temperature of 78.3°C (173°F) could be used. 10.6°C (19°F) lower than a 78.3°C (173°F) water bath would be 67.8°C (154°F); 3.9°C (7°F) lower than a 78.3°C (173°F) water bath would be 74.4°C (166°F). Hence, after immersing the thermometer that has been previously cooled, in the 78.3°C (173°F) bath, the stopwatch is started when the thermometer reads 67.8°C (154°F) and stopped when it reads 74.3°C (166°F).
NOTE: The test included the pasteurization temperature set points of 71.7°C (161°F) and 74.4°C (166°F). If the pasteurization temperature set points had been 71.7°C (161°F) and 79.4°C (175°F), it would not have been possible to include both set points within a 6.7°C (12°F) span. With these set points the test would have to be done separately for each set point.
Corrective Action: If the response time exceeds four (4) seconds, the thermometer should be replaced or returned for repair.
Reference: Item 16p.(B and E)
Application: To all continuous-flow pasteurizers, except those in which the FDD is located at the end of the cooler section.
Frequency: Upon installation and at least once each three (3) months thereafter.
Criteria: Five (5) seconds, under specified conditions.
Apparatus:
Method: Measure the time interval between the instant when the recording thermometer reads 7°C (12°F) below the cut-in temperature and the moment of cut-in by the recorder/controller. This measurement is made when the sensing element is immersed in a rapidly agitated water bath maintained at 4°C (7°F) above the cut-in temperature.
Procedure:
Corrective Action: If the response time exceeds five (5) seconds, the recorder/controller should be repaired.
Reference: Item 16p (D) and (E)
Used to control the operation of the booster pump.
Application: To all pressure switches controlling the operation of a booster pump on HTST pasteurizer systems employing regenerators.
Frequency: Upon installation; each three (3) months thereafter; after any change in the booster pump or the switch circuit; and/or whenever the pressure switch seal is broken.
Criteria: The booster pump shall not operate unless there is at least a 6.9 kPa (1 pound) pressure differential on the pasteurized milk or milk product side of the regenerator.
Apparatus: Sanitary pressure gauge and pneumatic testing device, for checking and adjusting pressure switch settings.
A simple pneumatic testing device may be made from a discarded 50 millimeters (2 inches)-7BX sanitary tee, with two (2) additional 13H nuts, one (1) of which is provided with a 16A cap, drilled and tapped for a 13 millimeters (½ inch) galvanized iron nipple for the air connection. A hose connection is made to a compressed air source in the milk plant by means of a snap-on fitting. The air pressure can be controlled by pressure-reducing valve (range 0-60 psi) followed by a 13 millimeters (½ inch) globe-type bleeder valve connected into the side outlet of a 13 millimeters (½ inch) tee installed between the pressure-reducing valve and the testing device. The pressure switch to be tested is disconnected from the pasteurizer and connected to another of the outlets of the sanitary tee, and the pressure gauge is connected to the third outlet of the sanitary tee. By careful manipulation of the air pressure reducing valve and the air bleeder valve, the air pressure in the testing device may be regulated slowly and precisely. In operating the device, care should be taken to avoid exposing the pressure switch and the sanitary pressure gauge to excessive pressure that may cause damage. This may be done by first closing off the air pressure regulating valve and opening fully the bleeder valve; these may then be manipulated slowly to bring the air pressure in the testing device within the desired range. A test light of proper voltage should be placed in-series with the pressure switch contact and in parallel with the electrical load, booster pump starter, so the actuation point may be readily determined.
Method: Check and make the adjustment of pressure switch to prevent the operation of the booster pump, unless the pressure of the pasteurized milk or milk product side of the regenerator is greater by at least 6.9 kPa (1 psi) than any pressure that may be generated on the raw side.
Procedure:
Application: Test 9.2.1 applies to all differential pressure controllers used to control the operation of booster pumps on HTST systems, or used to control the operation of FDDs on HHST systems and aseptic processing systems when a vacuum breaker is not located downstream from the holding tube.
Test 9.2.2 applies only to HTST systems.
Test 9.2.3 applies to the testing of HHST systems in which the differential pressure controller is used to control the operation of the FDD. Test 9.2.3 also applies to aseptic processing systems in which the differential pressure controller is used to control the FDD, milk or milk product divert system, milk or milk product divert valve or other acceptable control system.
Frequency: Upon installation; each three (3) months thereafter; and whenever the differential pressure controller is adjusted or repaired.
Criteria: The booster pump shall not operate, or the pasteurizer shall not operate in forward- flow, unless the milk or milk product pressure in the pasteurized side of the regenerator is at least 6.9 kPa (1 psi) greater than the milk or milk product pressure in the raw side of the regenerator. When the differential pressure controller is used to control the FDD on HHST or aseptic processing systems, and improper pressure occurs in the regenerator, the FDD shall move to the diverted-flow position and remain in diverted-flow until the proper pressures are re-established in the regenerator and all milk or milk product-contact surfaces between the holding tube and FDD have been held at or above the required pasteurization or aseptic processing temperature, continuously and simultaneously for at least the required time.
Apparatus: A sanitary pressure gauge and a pneumatic testing device, described in PRESSURE SWITCHES can be used for checking and adjusting the differential pressure switch setting. (Refer to Test 9.1)
Method: The differential pressure switch is checked and adjusted to prevent the operation of the booster pump, or prevent forward-flow, unless the milk or milk product pressure in the pasteurized, or aseptic, side of the regenerator is at least 6.9 kPa (1 psi) greater than the pressure in the raw side of the regenerator.
Procedure:
Method: Determine if the booster pump stops when the pressure differential is not properly maintained in the regenerator.
Procedure:
NOTE: If there is water in the HTST system, ensure that the recorder/controller probe and the pasteurized sensor ports are capped before the timing pump is turned on.
Corrective Action: If the booster pump fails to stop when the pressure differential is not maintained, have the milk plant maintenance personnel determine and correct the cause.
Application:
Apparatus: A sanitary pressure gauge and a pneumatic testing device, described in PRESSURE SWITCHES can be used for checking and adjusting the differential pressure switch setting. (Refer to Test 9.1)
Method: The differential pressure switch is checked and adjusted to prevent forward-flow, unless the milk or milk product pressure in the pasteurized side of the regenerator is at least 6.9 kPa (1 psi) greater than the pressure in the raw milk or milk product side of the regenerator. In the case of milk or milk product-to-water-to-milk or milk product regenerators, protected on the pasteurized or aseptic side, the "water side" of the regenerator shall be considered to be the "raw product side" for purposes of this Test.
Procedure:
NOTE: This test may be completed using a pneumatic testing device capable of producing differential pressures on the probes. This device should be capable of being operated, and be operated, in a manner so as to duplicate the conditions described above.
Application: To all booster pumps used for HTST systems
Criteria: The booster pump shall be wired so it cannot operate if the FDD is in the diverted position or if the timing pump is not in operation.
Apparatus:
Method: Determine if the booster pump stops by dropping the temperature and causing the FDD to divert.
Procedure:
NOTE: If there is water in the HTST system, ensure that the recorder/controller probe and the pasteurized sensor ports are capped before the timing pump is turned on.
Corrective Action: If the booster pump fails to stop when the FDD is in the diverted-flow position, have the milk plant maintenance personnel check the wiring and correct the cause.
Method: Determine if the booster pump stops when the timing pump is off.
Procedure:
NOTE: If there is water in the HTST system, ensure that the recorder/controller probe and the pasteurized sensor ports are capped before the timing pump is turned on.
Corrective Action: If the booster pump fails to stop when the timing pump has been turned off, have the milk plant maintenance personnel determine and correct the cause.
References: Item 16p (B), (C) and E)
Milk or milk product-flow controls shall be tested for milk or milk product temperature at cut-in and cut-out by one (1) of the following applicable tests at the frequency prescribed:
Application: All recorder/controllers used in connection with HTST pasteurizers, except those in which the FDD is located at the end of the cooler section.
Frequency: Upon installation; at least once each three (3) months thereafter by the Regulatory Agency, or HACCP qualified industry person, acceptable to the Regulatory Agency, qualified under Item 16p(E)2; daily by the milk plant operator; or when a regulatory seal has been broken.
Criteria: No forward-flow until the pasteurization temperature has been reached. Flow diverted before the temperature drops below the minimum pasteurization temperature.
Apparatus: No supplemental materials needed.
Method: By observing the actual temperature of the indicating thermometer at the instant forward-flow starts (cut-in) and stops (cut-out).
Procedure:
Corrective Action: Should the reading be below the minimum pasteurization temperature, the cut-in and cut-out mechanism and/or the differential temperature mechanism should be adjusted to obtain proper cut-in and cut-out temperatures by repeated tests. When compliance is achieved, seal the recorder/controller mechanism.
Application: All HHST pasteurizers and aseptic processing systems using indirect heating. When testing aseptic processing systems, the "milk or milk product divert system" or "milk or milk product divert valve" or "acceptable control system" may be substituted for the "FDD" when it is referenced in this Test.
Frequency: Upon installation; every three (3) months thereafter; and whenever the thermal controller seal is broken.
Criteria: The pasteurizer or aseptic processor shall not operate in forward-flow unless the pasteurization or aseptic processing temperature has been achieved. The milk or milk product flow shall be diverted at a temperature lower than the chosen pasteurization or aseptic processing standard.
Apparatus: No supplemental materials needed.
Method: The cut-in and cut-out temperatures are determined by observing the actual temperature in the constant temperature bath at which the two (2) sensing elements signal forward-flow (cut-in) and diverted-flow (cut-out).
Procedure:
Application: All HHST pasteurizers and aseptic processing systems using direct heating. When testing aseptic processing systems, the "milk or milk product divert system" or "milk or milk product divert valve" or "acceptable control system" may be substituted for the "FDD" when it is referenced in this Test.
Frequency: Upon installation; every three (3) months thereafter; and whenever the thermal-limit-controller seal is broken.
Criteria: The pasteurizer or aseptic processor shall not operate in forward-flow unless the pasteurization or aseptic processing temperature has been achieved. The milk or milk product flow shall be diverted at a temperature lower than the chosen pasteurization or aseptic processing standard.
Apparatus: No supplemental materials needed.
Method: The cut-in and cut-out temperatures are determined by observing the actual temperature in the constant temperature bath at which each of the three (3) sensing elements signals forward-flow (cut-in) and diverted-flow (cut-out).
Procedure:
Reference: Item 16p (B), (C) and (E)
Continuous-flow holding tubes shall be tested for holding times by one (1) of the following applicable tests:
Application: To all HTST pasteurizers employing a holding time of fifteen (15) seconds or longer.
Frequency: Upon installation; semi-annually thereafter; whenever the seal on the speed setting is broken; any alteration is made affecting the holding time, the velocity of the flow, such as the replacement of the pump, motor, belt, drive or driven pulleys, or a decrease in the number of HTST plates or the capacity of holding tube; or whenever a check of the capacity of the holding tube indicates a speedup.
Criteria: Every particle of milk or milk product shall be held for at least fifteen (15) seconds in both the forward and diverted-flow positions.
Apparatus:
Method: The holding time is determined by timing the interval for an added trace substance to pass through the holding tube. Although the time interval of the fastest particle of milk is desired, the conductivity test is made with water. The results found with water are converted to the milk flow time, by formulation, since a pump may not deliver the same amount of milk as it does water.
Procedure:
For all gear driven timing pumps; or for those homogenizers used as timing pumps, when the measured holding time for water is less than 120% of the legal holding time, complete Procedures 11, 12 and 13. For those homogenizers used as timing pumps, when the measured holding time for water is 120% or more of the legal holding time, Procedure 11 is optional and 12 and 13 are not required.
BY VOLUME:
The holding time for milk is equal to the holding time for water; times the quotient of the time it takes to deliver a volume of milk; divided by the time it takes to deliver the same volume of water.
Tm = Tw(Vm/Vw)
Where:
Tm = Adjusted product holding time for milk.
Tw = Holding time for water, the salt test results.
Vw = Time, usually in seconds, that it takes to pump a volume of water.
Vm = Time, usually in seconds, that it takes to pump the same volume of milk.
BY WEIGHT (Using specific gravity):
The holding time for milk is equal to the specific gravity of milk; times the holding time for water; times the quotient of the time it takes to deliver a measured weight of milk; divided by the time it takes to deliver the same weight of water.
Tm = 1.032xTw(Wm/Ww)
Where:
1.032 = The specific gravity of milk.
Tm = Adjusted product holding time for milk.
Tw = Holding time for water, the salt test results.
Wm = Time, usually in seconds, that it takes to pump a measured weight of milk.
Ww = Time, usually in seconds, that it takes to pump the same measured weight of water.
Corrective Action: When the computed holding time for milk is less than that required, either in forward-flow or diverted-flow, the speed of the timing pump shall be reduced or an adjustment made in the holding tube and the timing test repeated until a satisfactory holding time is achieved. Should an orifice be used to correct the holding time in diverted-flow, there should be no excessive pressure exerted on the underside of the valve seat of the FDD. Governors shall be sealed on motors that do not provide a constant speed as provided in Item 16p(B)5.b.
Application: To all HTST pasteurizers with a magnetic flow meter based timing system, used in lieu of a timing pump.
Frequency: Upon installation; semiannually thereafter; whenever a seal on the flow alarm is broken; any alteration is made affecting the holding time, the velocity of the flow or the capacity of holding tube; or whenever a check of the capacity indicates a speed up.
Criteria: Every particle of milk or milk product shall be held for at least a minimum holding time in both the forward and diverted-flow positions.
Apparatus:
Method: The holding time is determined by timing the interval for an added trace substance to pass through the holding tube.
Procedure:
Corrective Action: When the computed holding time for milk is less than that required, the set point on the flow recorder/controller shall be decreased, or an adjustment made in the holding tube, and the timing test repeated until a satisfactory holding time is achieved.
Application: To all continuous-flow pasteurization and aseptic processing systems using a magnetic flow meter based timing system to replace a timing pump. When testing aseptic processing systems, the "milk or milk product divert system" or "milk or milk product divert valve" or "acceptable control system" may be substituted for the "FDD" when it is referenced in this Test.
Frequency: Upon installation; semiannually thereafter; whenever the seal on the flow alarm is broken; any alteration is made affecting the holding time, the velocity of the flow or the capacity of holding tube; or whenever a check of the capacity indicates a speedup.
Criteria: When flow rate equals or exceeds the value at which the holding time was measured, the flow alarm shall cause the FDD to assume the diverted position, even though the temperature of the milk or milk product in the holding tube is above the pasteurization or aseptic processing temperature.
Apparatus: None
Method: Adjust the set point of the flow alarm so that flow is diverted when the flow rate equals or exceeds the value at which the holding time was measured or calculated. (Refer to Procedure 3 or 4 of this Test)
Procedure:
NOTE: The appropriate temperature elements may be placed in a water or oil bath to simulate the normal pasteurization or aseptic processing temperature of the holding tube as an alternative to heating the water in the system above the pasteurization or aseptic processing temperature. Observation and recording of this temperature should be done as described in Procedures 3 and 4 below.
NOTE: When performing this Test on systems that operate above the boiling point of water, be sure that the system is cooling to avoid the possibility of serious burns.
Corrective Action: If the FDD does not move to the diverted position, when the frequency pen of the recorder/controller indicates a diversion, a modification or repair of the control wiring is required.
Application: To all continuous-flow pasteurization and aseptic processing systems using a magnetic flow meter based timing system to replace a timing pump. When testing aseptic processing systems, the when it is referenced in this Test.
Frequency: Upon installation; semiannually thereafter; whenever the seal on the flow alarm is broken; or any alteration is made affecting the holding time.
Criteria: Forward-flow occurs only when flow rates are above the loss-of-signal alarm set point.
Apparatus: None
Method: By observing the actions of the frequency pens on the recorder/controller and the position of the FDD.
Procedure:
Corrective Action: If the valve does not divert or the pens do not move, adjustment of the low flow/loss-of-signal alarm or a modification or repair of the control wiring is required.
Application: To all HTST pasteurizers using a magnetic flow meter based timing system to replace a timing pump.
Frequency: Upon installation; semiannually thereafter; whenever the seal on the flow alarm is broken; any alteration is made affecting the holding time, the velocity of the flow or the capacity of holding tube; or whenever a check of the capacity indicates a speedup.
Criteria: Forward-flow occurs only when flow rates are below the flow alarm set point and above the low flow/loss-of-signal alarm set point.
Apparatus: None
Method: By observing the recorder/controller readings along with the action of the frequency pen on the recorder/controller.
Procedure:
Corrective Action: If the cut-in or cut-out point occurs at a flow rate equal to or greater than the value at which holding time was measured, adjust the flow alarm to a lower set point and repeat the Test.
Application: To all HTST pasteurizers using a magnetic flow meter based timing system to replace a timing pump.
Frequency: Upon installation; semiannually thereafter; whenever the seal on the flow alarm is broken; any alteration is made affecting the holding time, the velocity of the flow or the capacity of the holding tube; or whenever a check of the capacity indicates a speedup.
Criteria: Following the flow cut-in, as described in Test 11.2D, forward-flow shall not occur until all milk or milk product in the holding tube has been held at or above pasteurization temperature for at least the minimum holding time.
Apparatus: Stopwatch
Method: Set the time delay equal to or greater than the minimum holding time.
Procedure:
Corrective Action: If the time delay is less than the minimum holding time, increase the time setting on the time delay and repeat Test 11.2E.
Application: To all HHST pasteurizers using indirect heating.
Frequency: When installed; semiannually thereafter; whenever the seal on the speed setting is broken; whenever any alteration is made affecting the holding time, the velocity of the flow, i.e., replacement of the pump, motor, belt, driver or driven pulley, decrease in number of heat-exchange plates or the capacity of holding tube; and whenever a check of the capacity indicates a speedup.
Criteria: Every particle of milk or milk product shall be held for the minimum holding time in both the forward and diverted-flow positions.
Apparatus: No supplemental materials needed.
Method: Fully developed laminar flow is assumed and holding tube length is calculated. An experimental determination of the pumping rate is required; this is accomplished by determining the time required for the pasteurizer to fill a vessel of known volume; converting these data by division to obtain flow rate in gallons per second; and multiplying this value by the proper value in Table 14 to determine the required holding tube length. Holding tube lengths for HHST pasteurizers with indirect heating for a pumping rate of 1 gallon/second are:
| Holding Time (sec.) |
Tubing Size (inches) | ||||
|---|---|---|---|---|---|
| 1 | 1 ½ | 2 | 2 ½ | 3 | |
| Holding Tube Length (inches) | |||||
| 1.0 sec. | 723.0 | 300.0 | 168.0 | 105.0 | 71.4 |
| 0.5 sec. | 362.0 | 150.0 | 84.0 | 52.4 | 35.7 |
| 0.1 sec. | 72.3 | 30.0 | 16.8 | 10.5 | 7.14 |
| 0.05 sec. | 36.2 | 15.0 | 8.4 | 5.24 | 3.57 |
| 0.01 sec. | 7.23 | 3.0 | 1.68 | 1.05 | .714 |
Procedure:
Alternate Procedure for Measuring Flow Rate: For pasteurizers of large capacity, the method of measuring flow rate at the discharge of the pasteurizer is inconvenient. The following alternate Test procedure may be used. Remove the divert line from the constant-level tank and turn off the milk or milk product pump feeding the constant-level tank. Suspend a sanitary dipstick in the constant-level tank and operate the pasteurizer at maximum capacity. Record the time required for the water level to move between two (2) graduations on the dipstick. The volume of water is calculated from the dimensions of the constant-level tank and the drop in water level. Flow rate is determined as follows: Divide the volume of water removed from the constant-level tank by the time, in seconds, required to remove it. Then use Table 14 to calculate the required holding tube length.
Alternate Procedures for Determination of Holding Tube Length for Non-Standard Pipe Size: Alternatively, if the holding tube is of non-standard pipe sizes, the holding tube length may be accurately calculated from the following equation:
L = 588 Qt/D2
Where:
L = Holding tube length (inches)
Q = Pumping rate (gallons per second)
t = Holding time standard (seconds)
D = Inside diameter of holding tube (inches)
After the minimum required holding tube length is obtained from the calculation above, the length of the holding tube is measured to determine that it is at least as long as the calculated length. The holding tube may include fittings or, for the shorter holding times, may be a fitting. The centerline length of the fitting is treated as an equivalent length of straight pipe. The centerline distance may be measured by forming a flexible steel tape along the centerline of the fitting.
Corrective Action: If the length of the holding tube is shorter than the calculated length, reseal the timing pump at a slower maximum speed, or lengthen the holding tube, or both, and repeat this Procedure.
Application: To all HHST pasteurizers using direct contact heating.
Frequency: When installed; semiannually thereafter; whenever the seal on the speed setting is broken; whenever any alteration is made affecting the holding time, the velocity of the flow, i.e., replacement of pump, motor, belt, driver or driven pulley, or a decrease in the number of heat exchange plates; or the capacity of the holding tube; and whenever a check of the capacity indicates a speedup.
Criteria: Every particle of milk or milk product shall be held for the minimum holding time in both forward and diverted-flow positions.
Apparatus: No supplemental materials needed.
Method: Fully developed laminar flow and a temperature increase by steam injection of 67°C (120°F) are assumed, the processor chooses the temperature-time standard and the required holding tube length is calculated from an experimental determination of the pumping rate.
Procedure:
| Holding time (sec.) |
Tubing Size (inches) | ||||
|---|---|---|---|---|---|
| 1 | 1 ½ | 2 | 2 ½ | 3 | |
| Holding tube length (inches) | |||||
| 1 sec. | 810.0 | 336.0 | 188.0 | 118.0 | 80.0 |
| 0.5 sec. | 405.0 | 168.0 | 94.0 | 59.0 | 40.0 |
| 0.1 sec. | 81.0 | 33.6 | 18.8 | 11.8 | 8.0 |
| 0.05 sec. | 40.5 | 16.8 | 9.40 | 5.90 | 4.0 |
| 0.01 sec. | 8.10 | 3.36 | 1.88 | 1.18 | 0.8 |
Alternate Procedure for Measuring Flow Rate: For pasteurizers of large capacity, the method of measuring flow rate at the discharge of the pasteurizer is inconvenient. The following alternate Test procedure may be used. Remove the divert line from the constant-level tank and turn off the milk or milk product pump feeding the constant-level tank. Suspend a sanitary dipstick in the constant-level tank and operate the pasteurizer at maximum capacity. Record the time required for the water level to move between two graduations on the dipstick. The volume of water is calculated from the dimensions of the constant-level tank and the drop in water level. Flow rate is determined as follows: Divide the volume of water, in gallons, removed from the constant- level tank by the time, in seconds, required to remove it. Then use Table 15 to calculate the required holding tube length.
Alternate Procedures for Determination of Holding Tube Length for Non-Standard Pipe Size: Alternatively, if the holding tube is of non-standard pipe sizes, the holding-tube length may be accurately calculated from the following equation:
L = (588 Qt x 1.12)/D2
Where:
L = Holding-tube length (inches)
Q = Pumping rate (gallons per second)
t = Holding time standard (seconds)
D = Inside diameter of holding tube (inches).
1.12 = 12% expansion for steam
After the minimum required holding tube length is obtained from the calculation above, the length of the holding tube is measured to determine that it is at least as long as the calculated length. The holding tube may include fittings or, for the shorter holding times, may be a fitting. The centerline length of the fitting is treated as an equivalent length of straight pipe. The centerline distance may be measured by forming a flexible steel tape along the centerline of the fitting.
Corrective Action: If the length of the holding tube is shorter than the calculated length, reseal the timing pump at a slower maximum speed, or lengthen the holding tube, or both, and repeat the Procedure.
Application: To all HHST pasteurizers using direct steam infusion heating and using a steam pop-off valve and a vacuum chamber orifice in place of a timing pump.
Frequency: Upon installation; every three (3) months thereafter; or when a regulatory seal has been broken.
Criteria: Every particle of milk or milk product shall be held for the minimum holding time in both forward and diverted-flow positions.
Apparatus: No supplemental materials needed.
Method:
Procedure:
Corrective Action: If the length of the holding tube is shorter than the calculated length, reseal the timing pump at a slower maximum speed, or lengthen the holding tube, or both, and repeat the Test.
References: Items 16p (B) and (E)
Thermal-limit-controllers used with HHST and aseptic processing systems that have the FDD located downstream from the regenerator and/or cooler shall be tested by one (1) of the following applicable Tests at the frequency prescribed:
Application: To all HHST pasteurizers and aseptic processing systems using indirect heating. When testing aseptic processing systems, the "milk or milk product divert system" or "milk or milk product divert valve" or "acceptable control system" may be substituted for the "FDD" when it is referenced in this Test.
Frequency: Upon installation; every three (3) months thereafter; or when a regulatory seal has been broken.
Criteria: The pasteurizer, or aseptic processing equipment, shall not operate in forward-flow until the milk or milk product surfaces downstream from the holding tube have been sanitized, or in the case of aseptic processing equipment, sterilized. Upon start-up, surfaces shall be exposed to fluid at pasteurization temperature, or in the case of aseptic processing equipment, sterilizing temperature, for at least the required pasteurization or sterilization time. If the milk or milk product temperature falls below the pasteurization or sterilization standard in the holding tube, forward-flow shall not be re-achieved until the milk or milk product-contact surfaces downstream from the holding tube have been re-sanitized, or in the case of aseptic processing equipment, re-sterilized.
Apparatus: A constant temperature bath of water, or oil, and the test lamp from the pneumatic testing device described in Test 9.1 may be used to check the control-sequence logic of the thermal-limit-controller.
Method: The control-sequence logic of the thermal-limit-controller is determined by monitoring the electric signal from the thermal-limit-controller during a series of immersions and removals of the two (2) sensing elements from a bath heated above the cut-in temperature.
Procedure:
Corrective Action: If the control-sequence logic of the thermal-limit-controller does not follow these Procedures, the instrument shall be reconfigured to conform to this logic.
Application: To all HHST pasteurizers and aseptic processing systems using direct contact heating. When testing aseptic processing systems, the "milk or milk product divert system" or "milk or milk product divert valve" or "acceptable control system" may be substituted for the "FDD" when it is referenced in this Test.
Frequency: Upon installation; every three (3) months thereafter; or when a regulatory seal has been broken.
Criteria: The pasteurizer, or aseptic processing equipment, shall not operate in forward-flow until the milk or milk product surfaces downstream from the holding tube have been sanitized, or in the case of aseptic processing equipment, sterilized. Upon start-up, surfaces shall be exposed to fluid at pasteurization temperature, or in the case of aseptic processing equipment, sterilizing temperature for at least the required pasteurization or sterilization time. If the milk or milk product temperature falls below the pasteurization or sterilization standard in the holding tube, forward-flow shall not be re-achieved until the milk or milk product-contact surfaces downstream from the holding tube have been re-sanitized, or in the case of aseptic processing equipment, re-sterilized.
Apparatus: A constant temperature bath of water, or oil, and the test lamp from the pneumatic testing device described in Test 9.1 can be used to check the control-sequence logic of the thermal-limit-controller.
Method: The control-sequence logic of the thermal-limit-controller is determined by monitoring the electric signal from the thermal-limit-controller during a series of immersions and removals of the three (3) sensing elements from a bath heated above the cut-in temperature.
Procedure:
Corrective Action: If the control-sequence logic of the thermal-limit-controller does not follow these Procedures, the instrument shall be reconfigured to conform to this logic.
Reference: Item 16p (B) and (E)
Application: To all HHST pasteurizers and aseptic processing systems, which are capable of operating with product in forward-flow mode, with less than 518 kPa (75 psig) pressure in the holding tube. When testing aseptic processing systems, the "milk or milk product divert system" or "milk or milk product divert valve" or "acceptable control system" may be substituted for the "FDD" when it is referenced in this Test.
Frequency: Upon installation; every three (3) months thereafter; whenever the pressure switch seal is broken; and whenever the operating temperature is changed.
Criteria: The pasteurizer or aseptic processor shall not operate in forward-flow unless the product pressure in the holding tube is at least 69 kPa (10 psi) above the boiling pressure of the product.
Apparatus: A sanitary pressure gauge and a pneumatic testing device described in Test 9.1 can be used for checking and adjusting the pressure switch setting.
Method: The pressure switch is checked and adjusted so as to prevent forward-flow unless the milk or milk product pressure in the holding tube is at least 69 kPa (10 psi) above the boiling pressure of the milk or milk product.
Procedure:
For each HHST pasteurizer or aseptic processing system temperature, the milk or milk product pressure switch setting is as follows:
Figure 44. Pressure Switch Setting
This pressure setting shall be adjusted upward by the difference between the local normal atmospheric pressure and the atmospheric pressure at sea level.
Reference: Item 16p (B) and (E)
Application: To all HHST pasteurizers and aseptic processing systems using direct contact heating. When testing aseptic processing systems, the "milk or milk product divert system" or "milk or milk product divert valve" or "acceptable control system" may be substituted for the "FDD" when it is referenced in this Test.
Frequency: Upon installation; every three (3) months thereafter; and whenever the differential pressure controller seal is broken.
Criteria: The pasteurizer or aseptic processor shall not operate in forward-flow unless the milk or milk product pressure drop across the injector is at least 69 kPa (10 psi).
Apparatus: A sanitary pressure gauge and a pneumatic testing device described in Test 9.1 can be used for checking and adjusting the differential pressure controller.
Method: Adjust the differential pressure switch to prevent forward-flow, unless the differential pressure across the injector is at least 69 kPa (10 psi).
Procedure:
Application: To all electronic controls used to assure compliance with public health safeguards on pasteurization and aseptic processing equipment that are installed in milk plants where hand-held communication devices are used.
Frequency: Upon installation; alteration of the electronic controls; every three (3) months thereafter; and whenever the type or wattage of the hand-held communication device(s) used in that facility is changed. Once a hand-held communication device has been shown to cause a given electronic control device to react adversely, the Test does not have to be repeated every three (3) months using that specific hand-held communication device on the adversely affected electronic control device. If the electronic control device is altered or there is a change in the hand-held communication device used, the electronic control device would be required to be tested.
Criteria: The use of hand-held devices shall have no adverse effect on the public health safeguards.
Apparatus: One (1) hand-held device representing each make and model used in the facility. The device must be operating at maximum output, fully charged.
Method: By observing the actual effect of the hand-held communication device, it can be determined if that device can be used near that equipment without compromising a public health safeguard.
Procedure:
For Example: For temperature set point, operate the pasteurizer or aseptic processor on water in diverted-flow in the "Product" mode, at a steady temperature within 3°C (5°F) of the lowest cut-in temperature. In this example, an adverse effect is defined as forward-flow movement of the FDD or any artificial increase in temperature.
Corrective Action: Have the facility check for shielding, grounding and other
installation concerns and retest. Until a solution, acceptable to the Regulatory
Agency, can be found that does not adversely affect the public health safeguards,
the hand-held device may not be used in the area of the public health safeguards.
