GB/T 39948-2021 PDF in English
GB/T 39948-2021 (GB/T39948-2021, GBT 39948-2021, GBT39948-2021)
Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Name of Chinese Standard | Status |
GB/T 39948-2021 | English | 290 |
Add to Cart
|
0-9 seconds. Auto-delivery.
|
Method of heat distribution test for food thermal sterilization equipments
| Valid |
Standards related to (historical): GB/T 39948-2021
PDF Preview
GB/T 39948-2021: PDF in English (GBT 39948-2021) GB/T 39948-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.050
X 70
Method of heat distribution test for food thermal
sterilization equipment
ISSUED ON: MARCH 09, 2021
IMPLEMENTED ON: APRIL 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Principle of heat distribution test ... 6
5 Heat distribution test instruments ... 6
6 Preparation before heat distribution test ... 7
7 Heat distribution test records ... 19
8 Heat distribution data analysis ... 19
9 Test report ... 21
10 Anomaly analysis ... 22
11 Recommendations on the number of heat distribution tests and validity
period for food thermal sterilization equipment ... 23
Appendix A (Informative) Questionnaire of sterilization equipment and ancillary
facilities ... 24
Appendix B (Informative) Heat distribution test data analysis table of thermal
sterilization equipment (example) ... 26
Appendix C (Informative) Number of heat distribution tests for food thermal
sterilization equipment ... 29
Appendix D (Informative) Validity period of heat distribution test results ... 30
Method of heat distribution test for food thermal
sterilization equipment
1 Scope
This Standard specifies the terms and definitions, principle of heat distribution
test, heat distribution test instruments, preparation before heat distribution test,
heat distribution test records, heat distribution data analysis, test report, and
anomaly analysis requirements of heat distribution test for food thermal
sterilization equipment; and gives recommendations on the number of food heat
penetration tests and validity period.
This Standard applies to the heat distribution test for thermal sterilization
equipment, such as high-pressure static type (vertical, horizontal, including
spray type, full water type), rotary type, high-pressure basketless type,
hydrostatic pressure type, atmospheric-pressure water-bath continuous type,
atmospheric-pressure tunnel continuous type, atmospheric-pressure steam
box, and water-bath sterilization tank (pool), which use steam, hot water, steam-
air-water, or steam-air mixture as heat-transfer medium.
This Standard does not apply to the heat distribution test of microwave heating
and flame heating sterilization equipment.
2 Normative references
The following documents are indispensable for the application of this document.
For the dated references, only the editions with the dates indicated are
applicable to this document. For the undated references, the latest edition
(including all the amendments) are applicable to this document.
GB 8950 Hygienic specifications of cannery
GB/T 20938 Good manufacturing practice for canned food enterprises
JJF 1366 Calibration Specification of Temperature Data Acquisition
Instruments
QB/T 5218 Terms of canned food industries
5.2 Temperature display device of sterilization equipment
It shall meet the requirements of GB 8950.
5.3 Automatic temperature recorder of sterilization equipment
It shall meet the requirements of GB 8950.
5.4 Pressure gauge of sterilization equipment
It shall meet the requirements of GB 8950.
5.5 Pressure recorder of sterilization equipment
It shall meet the requirements of GB/T 20938.
6 Preparation before heat distribution test
6.1 Requirements for thermal sterilization equipment and ancillary
facilities
6.1.1 The thermal sterilization equipment and sterilization ancillary facilities to
be tested shall meet the requirements of GB/T 20938; including the
requirements of devices such as exhaust pipe diameter, exhaust valve type,
steam pipe diameter, electronic thermometer, air release valve, circulating
pump. Before the test, it shall check and ensure that the supply of water,
electricity, steam, compressed air, etc. is in a normal state. In the heat
distribution test, the ratio OF the opening area of the loading bottom plate and
packaging container separation plate used TO the entire plate area shall meet
the following requirements: No less than 20% for steam sterilization; no less
than 30% for hot water sterilization.
6.1.2 Before use, the temperature data acquisition instrument shall be
calibrated. The calibration method shall meet the requirements of JJF 1366:
That is, in a standard constant-temperature oil bath or other constant-
temperature facilities, it is checked against a mercury thermometer or electronic
thermometer of known accuracy (division value needs to be 0.1 °C or better).
Generally, a fixed-point temperature calibration method is used. For example,
fixed-point calibration is carried out on the commonly-used sterilization
temperatures 100 °C, 116 °C, 121 °C or other specific sterilization temperature
points. The deviation value BETWEEN the recorded value of the temperature
measurement data recorder AND the mercury thermometer or electronic
thermometer of known accuracy shall be recorded and archived; and corrected
during data processing.
thermometer of the sterilization equipment;
2) Place 1 temperature measurement probe close to the sensor of the
automatic temperature recorder of the sterilization equipment. If the
mercury thermometer and the automatic temperature recorder sensor
are located at the same place, there is no need to repeatedly place the
temperature measurement probe;
3) Place 1 temperature measurement probe at the axial center of the
sterilization basket (usually this location is at a lower temperature);
4) Between the bottom and the upper container layers of the sterilization
basket, according to the principle of uniform distribution, select the
location for placing 1 temperature measurement probe respectively;
5) For the sterilization basket close to both ends of the sterilization
equipment, it is possible to respectively place 1 temperature
measurement probe between the bottom or the upper container layers
near the sterilization equipment door and pot tail;
6) If temperature measurement probe is to be added, in addition to the
above locations, it can be randomly placed in other locations of the
sterilization basket;
7) 1 temperature measurement probe shall be placed at the vacuum
suction cup where the partition is automatically loaded.
For the locations of the temperature measurement probe, it is possible to
refer to Figure 1 and Figure 2.
b) The location of the temperature measurement probe of the basketless
sterilization equipment is determined according to the following principles:
1) The structure of the basketless sterilization equipment is special. Most
of its mercury thermometer and recorder temperature measurement
probes are installed at the bottom of the sterilization equipment; so
when the heat distribution points are placed, the temperature sensing
heads next to these two positions can be placed first. When placing, it
is best to use special tools to complete positioning;
2) For the rest, fix the temperature measurement probes on the marked
food packaging containers. According to the set time interval, in the
direction of human intervention, let them successively drop from the top
of the sterilization equipment into the buffer water in the sterilization
equipment. And randomly stack in the sterilization equipment in
disorder;
carrier (plate/tank/basket/drawer type) on the same horizontal line at one time.
6.3.3.3 Atmospheric-pressure continuous sterilization equipment
According to the width of the conveyor chain, every 200 mm~250 mm,
simultaneously put all the temperature measurement probes into the entrance
end of the input chain; or put them in groups and staggered at the same time.
6.4 Specification of packaging container for heat distribution test
6.4.1 The packaging container used for testing shall be the smallest-
specification packaging container used by the production of the enterprise
under the test.
6.4.2 If the enterprise is producing a product with the smallest-specification
packaging container, use that product for testing. If the packaging container of
the production line is not the smallest specification, the smallest-specification
packaging container is filled with water, to simulate the product (commonly
known as water can) or other simulants test.
6.4.3 The heat distribution test of the rolling atmospheric-pressure continuous
sterilization equipment is not limited by the container specification. However,
the heat distribution test of the bucket or tank type atmospheric-pressure
continuous sterilization equipment still needs to be carried out using the product
packaged in the smallest specification.
6.5 Initial temperature of canned food
When testing the heat distribution, the initial temperature of canned food shall
be slightly lower than or refer to the initial temperature in the sterilization
specification.
6.6 Temperature data sampling interval
The temperature sampling time can be self-defined. The temperature data is
usually collected every 0.5 min. If the sterilization time is short, the interval time
for collecting the temperature can be shortened. Based on the sterilization
constant-temperature stage, each temperature measurement probe shall
collect no less than 25 temperature data.
Use filled can for heat distribution test. No matter what type of temperature data
acquisition instrument, only after the entire sterilization process is completed,
can the temperature data acquisition be terminated.
If the heat distribution test is performed with a water can as a load, after 15 min
of constant temperature, the data acquisition can be ended; and enter the
to be sterilized. After the whole process of heating, constant temperature,
sterilization and cooling, the heat distribution in the sterilization equipment can
be obtained.
6.7.5 High-pressure hot water sterilization
For high-pressure and high-temperature hot water sterilization operations using
hot water as the heat-transfer medium (including full water type and spray type),
after the water is injected to the specified water level, start to heat up. When
the water temperature reaches 80 °C, write down the time; and continue to heat
to the sterilization constant temperature. The time period from 80 °C to the
sterilization constant temperature is defined as the come-up time (CUT for
short).
After reaching the sterilization temperature, the sterilization constant
temperature timing can be started.
At the end of the constant temperature, enter the cooling stage and complete
the whole process of hot water sterilization.
Note 1: In view of the fact that the enthalpy of hot water is not as high as that of steam, the
heat transfer rate during sterilization is not as fast as steam; and the temperature
in the sterilization equipment is not easy to reach uniformity; so a reasonable come-
up time needs to be specified. The U.S. FDA "Minimum CUT" is quoted here, which
means: After the minimum come-up time of the sterilization equipment, the
temperature in the whole pot has become uniform. If the specified minimum come-
up time is 15 min, but the actual come-up takes 14 min to reach the sterilization
constant temperature, at this time, the sterilization timing shall not be started. It is
necessary to wait for another 1 min and reach the specified 15 min (that is, the two
conditions of temperature and time are met at the same time) before the
sterilization timing can be started. The purpose is to ensure that the temperature
in the sterilization equipment is uniform.
Note 2: Due to the different inlet water temperature, products, and seasons of the
sterilization operation, the actual initial water temperature in the sterilization
equipment is bound to be inconsistent. In order to have a unified starting point for
the set minimum come-up time, this Standard stipulates that the minimum come-
up time starts at 80 °C.
Note 3: After obtaining the minimum (shortest) come-up time from the heat distribution test
data, combined with the heating capacity of the sterilization equipment, the time
can be specified after adding a 10% to 15% time safety factor.
6.7.6 Basketless high-pressure sterilization
After the temperature measurement probes are placed from the top of the
a) After 3 min of constant temperature, the temperature discrete value of all
temperature measurement probes shall be reduced. Compared with the
reference temperature, the standard deviation (σi) of the temperature at
different locations in the sterilization equipment during the entire constant-
temperature process shall be less than 0.5 °C.
b) After the come-up stage of thermal sterilization is over, and within 1 min
of the constant temperature, the lowest temperature of the temperature
measurement probe is 1.67 °C (3.0 °F) lower than the reference
temperature (refers to the temperature measurement value of the
temperature measurement probe placed next to the mercury thermometer,
the same below), which is regarded as acceptable.
c) If the come-up stage is over, and within 3 min of constant temperature, the
lowest temperature of the temperature measurement probe is 0.56 °C
(1.0 °F) lower than the reference temperature, which is considered
acceptable.
8.3.2 Hot water sterilization equipment
If the following two conditions are met at the same time, the heat distribution
can be considered acceptable:
a) If the come-up stage is over, and within 6 min of constant temperature, the
lowest temperature of the temperature measurement probe is 1.1 °C
(2.0 °F) lower than the reference temperature, which is considered
acceptable.
b) The average temperature value 𝑋ത i of each temperature measurement
probe in the constant-temperature stage is compared with the re-average
temperature value 𝑋ധ of the average values 𝑋ത1, 𝑋ത2, 𝑋ത3, ..., 𝑋തn of all other
temperature measurement probes. The deviation value is within the range
of 0.56 °C.
8.3.3 Atmospheric-pressure sterilization equipment
When using atmospheric-pressure continuous tunnel sterilization equipment to
sterilize acidic foods, in the constant-temperature stage, in the heat distribution
test, the lowest temperature of the temperature measurement probe shall not
be lower than the sterilization reference temperature specified in the process.
9 Test report
It is recommended that the heat distribution test report includes the following:
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
|