New York Codes, Rules and Regulations
Title 1 - DEPARTMENT OF AGRICULTURE AND MARKETS
Chapter I - Milk Control
Subchapter A - Dairy Products (Article 4, Agriculture and Markets Law)
Part 2 - Requirements For The Production, Processing, Manufacturing And Distribution Of Milk And Milk Products
Sanitation Requirements Applicable to the Processing and Manufacturing of Milk, Lowfat Milk, Skim Milk, Milk Products, Goat Milk, Goat Milk Products, Sheep Milk Products, Melloream and Frozen Desserts
Section 2.46 - High-temperature-short-time, (htst), continuous-flow pasteurization-item 16p(b)
Universal Citation: 1 NY Comp Codes Rules and Regs ยง 2.46
Current through Register Vol. 46, No. 12, March 20, 2024
(a) Indicating thermometers and recorder/controller instruments. All indicating thermometers and recorder/controller instruments and devices used in connection with the high-temperature-short-time, continuous-flow pasteurization of milk or milk products shall comply with the applicable specifications set forth in Appendix 3 of this Title.
(b) Automatic milk controller. Each high-temperature-short-time, continuous-flow pasteurization system shall be equipped with an automatic milk flow control of the diversion type, which complies with the following definition, specifications and performance requirements:
(1) Automatic
milk-flow controls. The term automatic milk-flow controls shall mean those
safety devices which control the flow of milk in relation to the temperature of
the milk, or heating medium and/or pressure, vacuum or other auxiliary
equipment. Milk-flow controls shall not be considered as part of the
temperature control equipment. Milk-flow controls shall be of the
flow-diversion type which automatically cause the diversion of the milk in
response to a sublegal pasteurization temperature. At sublegal temperatures,
flow-diversion devices return the milk to the raw milk side of the heating
system continuously until legal pasteurization temperatures are obtained; at
which time, the device restores forward flow through the pasteurizer.
(2) Flow-diversion devices. All
flow-diversion devices used in continuous pasteurizers shall comply with the
following or equally satisfactory specifications:
(i) Forward flow of subtemperature milk, due
to the omission or looseness of the connecting clip, shall be prevented by
making the valve and its actuating mechanism integral; or, where there is a
connecting device, by making it impossible to assemble the valve and its
actuating mechanism, except in such manner that it will function properly; or,
where there is a connecting device which may be omitted or shaken loose by
providing for pushing, instead of pulling, the valve to the diverted position;
or by providing that the pump will shut down when the milk is below the
pasteurization temperature and the valve is not in the fully diverted position;
or by any other equally satisfactory means.
(ii) When a packing gland is used to prevent
leakage around the actuating stem, it shall be impossible to tighten the stem
packing nut to such an extent as to prevent the valve from assuming the fully
diverted position.
(iii) A leak
escape shall be installed on the forward-flow side of the valve seat. However,
when back pressure is exerted on the forward-flow side of the valve seat, while
the milk-flow is being diverted, the leak escape should lie between two valve
seats, or between two portions of the same seat, one upstream and the other
downstream from the leak escape. The leak escape shall be designed and
installed to discharge all leakage to the outside, or to the constant-level
tank through a line separate from the diversion line, provided that, when
leakage is discharged to the constant-level tank, a sight glass shall be
installed in the leak escape line to provide a visual means of leak
detection.
(iv) The closure of the
forward-flow seat shall be sufficiently tight so that leakage past it will not
exceed the capacity of the leak escape device, as evidenced when the
forward-flow line is disconnected; and in order that proper seating may not be
disturbed, the length of the connecting rod shall not be adjustable by the
user.
(v) The flow-diversion device
shall be so designed and installed that failure of the primary motivating power
shall automatically divert the flow of milk.
(vi) The flow-diversion device shall be
located downstream from the holder. The flow-control sensor shall be located in
the milk line not more than 18 inches upstream from the flow-control
device.
(vii) In the case of
higher-heat-shorter-time (HHST) pasteurizing systems utilizing the temperatures
of 191° F (89° C) and above and holding times of one second and less,
the flow-diversion device may be located downstream from the regenerator and/or
cooler sections; provided that, when the flow-diversion device is located
downstream from the regenerator and/or cooler section, the flow-diversion
device shall be automatically prevented from assuming the forward-flow position
until all product-contact surfaces between the holding tube and flow-diversion
device have been held at or above the required pasteurization temperature
continuously and simultaneously for at least the required pasteurization time
as set forth in section
2.44 of
this Part.
(viii) The pipeline from
the diversion port of the flow-diversion device shall be self-draining, and
shall be free of restrictions or valves, unless such restrictions or valves are
so designed that stoppage of the diversion line cannot occur.
(ix) When it is used, the pipeline from the
leak detector port of the flow-diversion device shall be self-draining, and
shall be free of restrictions or valves, unless such restrictions or valves are
so designed that stoppage of the leak detector line cannot occur.
(3) Milk-flow controller
instrumentation. The following requirements shall be met with respect to the
instrumentation of the milk-flow controller:
(i) The thermal limit controller shall be set
and sealed so that forward flow of product cannot start unless the temperature
at the controller sensor is above the required pasteurization temperature as
defined in section
2.2(a)
of this Part for the milk or milk product and the process used, nor continue
during descending temperatures when the temperature is below the required
pasteurization temperature. The seal shall be applied by the commissioner after
testing, and shall not be removed without immediately notifying the
commissioner. The system shall be so designed that no milk can be bypassed
around the controller sensor which shall not be removed from its proper
position during the pasteurization process. The cut-in and cut-out milk
temperatures, as shown by the indicating thermometer, shall be determined at
the beginning of each day's operation and entered upon the recorder chart daily
by the plant operator.
(ii) In the
case of HHST pasteurization systems, utilizing the temperatures of 191° F
(89° C) and above, the holding times of one second or less, with the
flow-diversion device located downstream from the regenerator and/or cooler
section, additional temperature controllers and timers shall be interwired with
the thermal limit controller, and the control system shall be set and sealed so
that forward flow of product cannot start until all product-contact surfaces
between the holding tube and flow-diversion device have been held at or above
the required pasteurization temperature, continuously and simultaneously for at
least the required pasteurization time as set forth in section
2.44 of
this Part. The control system shall also be set and sealed so that forward flow
cannot continue when the temperature of the product in the holding tube is
below the required pasteurization temperature. The seal shall be applied by the
commissioner after test, and shall not be removed without immediately notifying
the commissioner. The system shall be so designed that no product can be
bypassed around the control sensors, which shall not be removed from their
proper position during the pasteurization process. For these HHST systems,
daily measurement by the operator of the cut-in and cut-out temperatures is not
required.
(iii) Manual switches for
the control of pumps, homogenizers or other devices which produce flow through
the holder, shall be wired so that the circuit is completed only when the milk
is above the required pasteurization temperature as set forth in section
2.44 of
this Part for the milk or milk product and the process used, or when the
diversion device is in the fully diverted position.
(4) Holding tube.
(i) Holders shall be designed to provide for
the holding of every particle of milk or milk product for at least the time
required in section
2.2(a)
of this Part for the milk or milk product and the process used.
(ii) The holder shall be so designed that the
simultaneous temperature difference between the hottest and coldest milk in any
cross-section of flow at any time during the holding period will not be greater
than one degree Fahrenheit (one-half degree Celsius). This requirement may be
assumed to have been satisfied without test in tubular holders of seven inches
or smaller diameter which are free of any fittings through which the milk may
not be thoroughly swept.
(iii) No
device shall be permitted for short-circuiting a portion of the holder to
compensate for changes in rate of milk flow. Holding tubes shall be installed
so that sections of pipe cannot be left out, resulting in a shortened holding
time.
(iv) The holding tube shall
be arranged to have a continuously upward slope in the direction of flow of not
less than 0.25 inch per foot.
(v)
Supports for tubes shall be provided to maintain all parts of holding tubes in
a fixed position, free from any lateral or vertical movement.
(vi) The holder shall be so designed that no
portion between the inlet and the flow-control temperature sensor is
heated.
(vii) The holding time for
the HHST processes must be determined from the pumping rate rather than by the
salt conductivity test, because of the short holding tube. The holding tube
length must be such that the fastest flowing particle of any product will not
traverse the holding tube in less than the required holding time. Since laminar
flow (the fastest flowing particle travels twice as fast as the average flowing
particle) can occur in the holding tube during pasteurization of high-viscosity
products, holding tube lengths are calculated as twice the length required to
hold the average flow for the time standard.
(viii) With the steam injection processes,
the holding time is reduced because the product volume increases as the steam
condenses to water during heating in the injector. This surplus water is
evaporated as the pasteurized product is cooled in the vacuum chamber. For
example, with a 120° F (66° C) increase by steam injection, which is
probably the maximum temperature rise that will be used, a volume increase of
12 percent will occur in the holding tube. The measurement of the average flow
rate at the discharge of the pasteurizer does no reflect this volume increase
in the holding tube. However, this volume increase, i.e., holding time
decrease, must be considered in the calculations.
(ix) With the steam injection process a
pressure limit indicator is needed in the holding tube to keep the heated
product in the liquid phase. The instrument must have a pressure switch so that
the flow-diversion device will move to the divert position if the product
pressure falls below a prescribed value. For operating temperatures between
191° F (89° C) and 212° F (100° C), the pressure switch must be
set at 10 pounds per square inch (psi). For units which have operating
temperatures above 212° F (100° C), the pressure switch must be set at
a pressure 10 psi above the boiling pressure of the product at its maximum
temperature in the holding tube.
(x) With the steam injection process, a
differential pressure limit indicator across the injector is needed to ensure
adequate isolation of the injection chamber. The instrument must have a
differential pressure switch so that the flow-diversion device will move to the
divert position if the pressure drop across the injector falls below 10
psi.
(5) Indicating and
recording thermometers.
(i) An indicating
thermometer shall be located as near a practicable to the temperature sensor of
the recorder/controller, but may be located a short distance upstream from the
latter where milk between the two thermometers does not differ significantly in
temperature.
(ii) The temperature
shown by the recorder/controller shall be checked daily by the plant operator
against the temperature shown by the indicating thermometer. Readings shall be
recorded on the chart. The recorder/controller shall be adjusted to read no
higher than the indicating thermometer.
(iii) The recorder/controller charts shall
comply with the applicable provisions of section
2.48
of this Part (Item 16p[D]).
(6) Flow-promoting devices.
(i) The pump, or pumps, and other equipment
which may produce flow through the holder shall be located upstream from the
holder, provided that pumps and other flow-promoting devices may be located
downstream from the holder if means are provided to eliminate negative pressure
between the holder and the inlet to such equipment. When vacuum equipment is
located downstream from the holder, an effective vacuum breaker, plus an
automatic means of preventing a negative pressure in the line between the
flow-diversion device and the vacuum chamber, shall be acceptable.
(ii) The speed of pumps or other
flow-promoting devices governing the rate of flow through the holder shall be
so controlled as to insure the holding of every particle of milk for at least
the time required, as set forth in section
2.44 of
this Part, for the milk or milk product and the process used. In all cases, the
motor shall be connected to the metering pump by means of a common drive shaft,
or by means of gears, pulleys or a variable-speed drive, with the gear box, the
pulley box, or the setting of the variable speed protected in such a manner
that the holding time cannot be shortened without detection by the
commissioner. This shall be accomplished by the application of a suitable
seal(s) after tests by the commissioner, and such seal shall not be broken
without immediately notifying the commissioner. The provision shall apply to
all homogenizers used as timing pumps. Variable speed drives used in connection
with the metering pump shall be so constructed that wearing or stretching of
the belt results in a slowdown, rather than a speedup, of the pump. The
metering or timing pump shall be of the positive displacement type.
(iii) The holding time shall be taken to mean
the flow time of the fastest particle of milk, at or above the required
pasteurization temperature, as set forth in section
2.44 of
this Part, for the milk or milk product and the process used, throughout the
holder section; i.e., that portion of the system that is outside of the
influence of the heating medium, and slopes continuously upward in the
downstream direction, and is located upstream from the flow-diversion device.
Tests for holding time shall be made when all equipment and devices are
operated and adjusted to provide for maximum flow. When a homogenizer is
located upstream from the holder, the holding time shall be determined with the
homogenizer in operation with no pressure on the homogenizer valves. Where
bypass lines are provided, either upstream or downstream from the metering
pump, the holding time shall be tested with both the regular and bypass line
open, unless the bypass valve is so designed that both lines cannot be open at
the same time. The holding time shall be tested during both forward and
diverted flow. If necessary to lengthen the holding time during diverted flow,
an identifiable restriction may be placed in the vertical portion of the
diversion pipeline. When vacuum equipment is located downstream from the
holder, the holding time shall be tested with the metering pump operating at
maximum flow, and the vacuum equipment adjusted to provide for the maximum
vacuum. The holding time shall be tested in both forward and diverted flow by
the regulatory agency initially, quarterly thereafter, after any alteration or
replacement that may effect the holding time, and whenever the seal of the
speed setting has been broken.
(7) Heating by direct addition of steam.
Steam injection is an inherently unstable process; accordingly, when steam is
injected into a fluid, condensation of the steam may not be completed inside
the injector unless the proper design criteria are used. Lack of complete
condensation inside the injector would cause temperature variations in the
holding tube that could lead to some product particles being processed below
pasteurization temperature. When culinary steam is introduced directly into
milk or milk products, as the means of terminal heating to achieve
pasteurization temperature, the steam injector shall be designed, installed and
operated to comply with the following or equally satisfactory specifications:
(i) The product and steam flows must be
isolated from pressure fluctuations inside the injection chamber. One method of
isolation is to insert supplementary orifices on the product inlet and the
heated product outlet of each injector. The two supplementary orifices must be
sized for at least a 10 psi product pressure drop across the injector during a
simulation of normal operations. Excessive vibrations, pressure fluctuations or
erratic noise levels indicate an unstable steam injection system and a need to
check the isolation of the injection chamber.
(ii) The product pressure in the holding tube
must be of sufficient magnitude to condense the steam and keep the heated
product in the liquid phase. If this pressure is too low, the resultant
vaporization in the holding tube will substantially reduce residence times. A
minimum product pressure in the holding tube of 10 psi for operating
temperatures from 191° F (89° C) through 212° F (100° C) is
satisfactory. For units which have operating temperatures above 212° F
(100° C), the pressure of the product in the holding tube must be at least
10 psi above the boiling pressure of the product at its maximum temperature in
the holding tube.
(iii) The process
should be as free as possible of noncondensable gases that may evolve from the
product or be carried in the steam supply. Any two-phase flow caused by the
noncondensable gases would displace the product in the holding tube, resulting
in reduced residence times. In addition, these gases in the steam supply may
also markedly alter the condensation mechanism at the point of injection.
Accordingly, the steam boiler shall be supplied with a deaerator. The deaerator
will aid in keeping the product in the holding tube as free as possible of
noncondensable gases.
(8) Prevention of product adulteration with
added water.
(i) When culinary steam is
introduced directly into the milk or milk product downstream from the
flow-diversion device, means shall be provided to preclude the addition of
steam to the product, unless the flow-diversion device is in the forward-flow
position. This provision may be satisfied by the use of an automatic steam
control valve with temperature sensor located downstream from the steam inlet,
or by the use of an automatic solenoid valve installed in the steam line and so
wired through the flow-diversion device controls that steam cannot flow unless
the flow-diversion device is in the forward-flow position.
(ii) When culinary steam is introduced
directly into the milk or milk product, automatic means shall be provided to
maintain a proper temperature differential between incoming and outgoing milk
to preclude dilution with water.
(iii) Where a water feed line is connected to
a vacuum condenser and the vacuum condenser is not separated from the vacuum
chamber by a physical barrier, means shall be provided to preclude the backup
and overflow of water from the vacuum condenser to the vacuum chamber. This
provision may be satisfied by the use of a safety shutoff valve, located on the
water feed line to the vacuum condenser, automatically actuated by a control
which will shut off the inflowing water, if for example, the condensate pump
stops and the water level rises above a predetermined point in the vacuum
condenser. This valve may be actuated by water, air or electricity, and shall
be so designed that failure of the primary motivating power will automatically
stop the flow of water into the vacuum condenser.
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