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GB/T 19495.7-2004 PDF in English


GB/T 19495.7-2004 (GB/T19495.7-2004, GBT 19495.7-2004, GBT19495.7-2004)
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GB/T 19495.7-2004: PDF in English (GBT 19495.7-2004)

GB/T 19495.7-2004
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.050
B 04
Detection of genetically modified organisms
and derived products - Methods for
sampling and sample preparation
ISSUED ON. APRIL 13, 2004
IMPLEMENTED ON. APRIL 13, 2004
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 General ... 7
5 Sampling, sample preparation tools and equipment ... 8
6 Sampling size ... 8
7 Sampling methods ... 11
8 Methods for sample preparation ... 14
9 Packaging, identification, and transport of sample ... 16
10 Sampling report ... 16
11 Restore sample ... 17
12 Health and safety ... 18
Foreword
GB/T 19495 “Detection of genetically modified organisms and derived products”
is a series of standards.
- GB/T 19495.1-2004 Detection of genetically modified organisms and
derived products - General requirements and definitions;
- GB/T 19495.2-2004 Detection of genetically modified organisms and
derived products - General requirements for laboratories;
- GB/T 19495.3-2004 Detection of genetically modified organisms and
derived products - Nucleic acid extraction;
- GB/T 19495.4-2004 Detection of genetically modified organisms and
derived products - Qualitative nucleic acid based methods;
- GB/T 19495.5-2004 Detection of genetically modified organisms and
derived products - Quantitative nucleic acid based methods;
- GB/T 19495.6-2004 Detection of genetically modified organisms and
derived products - Gene-chip detection;
- GB/T 19495.7-2004 Detection of genetically modified organisms and
derived products - Methods for sampling and sample preparation;
- GB/T 19495.8-2004 Detection of genetically modified organisms and
derived products - Protein based methods.
This Part was proposed by and shall be under the jurisdiction of Certification
and Accreditation Administration of the PRC.
This Part is approved and issued by General Administration of Quality
Supervision, Inspection and Quarantine of the PRC.
Main drafting organization of this Part. Liaoning Entry-Exit Inspection and
Quarantine Bureau of the PRC.
Participating drafting organizations of this Part. Laboratory of Animal and Plant
Quarantine of General Administration of Quality Supervision, Inspection and
Quarantine, Heilongjiang Entry-Exit Inspection and Quarantine Bureau of the
PRC, Guangdong Entry-Exit Inspection and Quarantine Bureau of the PRC,
Shenzhen Entry-Exit Inspection and Quarantine Bureau of the PRC, Shanghai
Entry-Exit Inspection and Quarantine Bureau of the PRC, South China
Agricultural University, Institute of Plant Protection of Shandong Academy of
Agricultural Sciences.
Detection of genetically modified organisms
and derived products - Methods for
sampling and sample preparation
1 Scope
This Part of GB/T 19495 specifies methods for sampling and sample
preparation for the detection of genetically modified products in plants and their
products.
This Part applies to the sampling and sample preparation of plants and their
products for the detection of genetically modified products.
2 Normative references
The clauses in the following documents, by reference in this Part of GB/T 19495,
constitute the clauses of this Part. For the dated references, the subsequent
amendments (not including errata content) or revisions do not apply to this Part.
However, parties which have reached an agreement according to this Part are
encouraged to study whether the latest edition of these documents can be used.
For the undated references, the latest edition is applicable to this Part.
GB/T 19495.1-2004 Detection of genetically modified organisms and derived
products - General requirements and definitions
GB/T 19495.2-2004 Detection of genetically modified organisms and derived
products - General requirements for laboratories
GB/T 19495.3-2004 Detection of genetically modified organisms and derived
products - Nucleic acid extraction
3 Terms and definitions
The following terms and definitions apply to this Part of GB/T 19495.
3.1 Consignment
Plants or plant products submitted, shipped, or received at one time, which may
consist of one or more lots.
3.11 Test sample, analytical sample
The sample for analysis or testing obtained by further homogenization of all or
part of the laboratory sample.
3.12 Restore sample
A certain number of samples taken from laboratory samples for future reference.
3.13 Acceptable GMO quality level
The acceptable amount of genetically modified products contained in the
specified consignment at the time of sampling acceptance, which is generally
expressed in mass percentage content.
4 General
4.1 General provisions
4.1.1 Samples taken and prepared shall be representative.
4.1.2 It shall ensure that sampling instruments are clean, dry, and have no odor.
The materials used in the sample preparation instruments and sample
containers shall not contaminate the sample to be taken.
4.1.3 To avoid cross contamination, it shall as far as possible use different
sampling and sample preparation instruments or equipment to extract and
prepare samples of different consignments; containers or packaging containing
samples shall be used as single as possible. If this is not possible (for example,
when using mechanical sampling equipment), after extracting and preparing
the sample of a consignment, all instruments and equipment shall be cleaned
using appropriate methods.
During all sampling processes, samples shall not be scattered, to prevent active
organisms from polluting the ecological environment.
Samples shall be prepared in physically isolated areas, to prevent
contamination of other areas or laboratories. The sample preparation area shall
be cleaned in time.
When necessary, USE DNA destruction agent to process sampling and sample
preparation instruments and equipment, sample containers, and sample
preparation areas.
When applicable, it shall refer to the provisions in GB/T 19495.1-2004 to
prevent pollution.
4.1.4 When sampling, samples shall be protected. Sampling instruments and
sample containers shall be stored in a clean environment, to avoid
contamination from foreign objects such as rain and dust.
4.1.5 All sampling operations shall be completed in the shortest possible time,
to avoid changes in the composition of sample. If a sampling step takes a long
time, the sample shall be stored in a closed container.
4.2 Lot grouping
First, according to the same contract, the same production lot number, the same
variety, and grade in the consignment, it shall be lotted. When the consignment
size is less than 10000 t, the maximum lot size is 500 t. When the consignment
size is greater than 10000 t, 10000 t divided into 20 lots is the base. For every
extra 1000 t, add 1 lot; if less than 1000 t, counted as 1 lot.
The consignment size divided by the number of lots is the lot size. For example,
a consignment of 600 t is divided into 2 lots, the lot size is 300 t. A consignment
of 13200 t is divided into 24 lots, the lot size is 550 t.
5 Sampling, sample preparation tools and equipment
According to the characteristics of the sample to be taken, sampling, sample
preparation instruments and equipment complying with the requirements of 4.1
shall be used. When extracting a solid sample, the size of the feed port of
sampling instruments or equipment shall be greater than 3 times the 95%
through size of the sample to be taken.
6 Sampling size
The sampling size specified in this Part is limited to the detection of genetically
modified products. The samples obtained are generally not used in other test
items. When the samples shall be divided, the sampling size shall be increased
as appropriate.
6.1 gives the minimum number of bulk samples under normal conditions. The
minimum number of bulk samples of processed products is converted
according to the provisions of 6.2. When there is no acceptable GMO quality
level, in general, at an acceptable GMO quality level of 1%, the minimum
number of bulk samples is determined. When the unit is large, such as potato,
pumpkin, coconut, beet, etc., or the number of grains cannot reach the minimum
number given in 6.1, in accordance with the provisions of 6.3, the minimum
number of bulk samples shall be determined.
the increments are taken.
When extracting solid samples, the mechanical sampling equipment used shall
be able to adjust the increment size and sampling frequency over a wide range
and facilitate inspection and cleaning. All materials shall have the same
opportunity to enter the sampling device of the mechanical sampler. When
manually sampling, according to a predetermined sampling interval, increments
shall be taken from a new section exposed or a stopped conveyor belt during
loading and unloading of materials. When sampling from a stopped conveyor
belt, a full bandwidth sample shall be taken. When extracting samples from a
new section of the materials, the upper, middle, and lower parts of the materials
shall be alternately extracted.
When sampling from a liquid delivery pipeline, according to a predetermined
sampling interval, the increment shall be taken. Before sampling, the sample
container shall be cleaned using the materials to be sampled.
7.1.2 Sampling from trucks, cabins, silos, containers, and other cargo
containers
Samples shall be taken from each cargo container. According to the materials
quantity and lot size carried in the cargo container, the number of increments
which shall be taken from each cargo container is calculated.
When taking solid samples, points shall be evenly distributed in the cargo
container for sampling. If possible, at each sampling point, extract samples of
the entire depth. When samples of the entire depth cannot be extracted, the
stratified sampling method shall be used; or during the loading-unloading
process, the method in 7.1.1 shall be used for sampling. When using stratified
sampling method for sampling, the cargo container is divided into at least 3
layers. When the quantity of materials contained in the cargo container is more
than 3 times the lot size, it shall be layered according to the lot size. First, points
are evenly distributed on the initial surface of the materials for extraction of
increments. When the materials are loaded-unloaded into the middle and lower
layers, points are evenly distributed on the exposed surfaces respectively for
extraction of increments.
When taking liquid sample, according to the ratio shown in Table 6, the sample
is taken in the upper, middle, and lower layers of cargo container.
method, the number of samples can be selected. If possible, before sampling,
it shall shake the liquid materials well; and pour the required amount into the
sample container as an increment. Otherwise, it shall, according to the shape
of package, with reference to the sampling locations and ratios in Table 6,
extract the increment or extract the sample of the entire depth.
8 Methods for sample preparation
8.1 General provisions
Unless otherwise agreed, the sample preparation process involved in this Part
generally includes mixing a sufficient number of increments to form the bulk
sample; reducing the bulk sample to obtain a laboratory sample; using
appropriate methods to prepare the restore sample; and appropriately
homogenizing the laboratory sample and reducing its particle size to obtain a
test sample.
Laboratory samples, test samples, and restore samples shall be prepared
separately in lots.
Measures to prevent pollution in sample preparation are carried out in
accordance with the provisions of GB/T 19495.2-2004.
8.2 Forming of bulk sample
The extracted increments can be mixed together to form the bulk sample.
If the bulk sample size formed at one time is large, the increments can be
divided into groups of consistent mass. When grouping increments, it shall try
to avoid dividing the consecutively extracted increments into one group. The
methods in 8.4 are used respectively to reduce for the same number of times;
and then the reduced samples obtained are mixed into a bulk sample. The
number of reductions shall be such that the bulk sample obtained is not less
than 4 times the laboratory sample size.
8.3 Preliminary treatment of sample
Before preparing the sample, if necessary preliminary treatment of the
extracted sample to be taken, such as peeling (shelling), dewatering, oil
removal, etc., the change in sample mass before and after preliminary
treatment shall be recorded. It can be implemented in accordance with the
provisions of GB/T 19495.3-2004.
8.4 Crushing, grinding, and reducing
specification, to obtain a laboratory sample.
8.6 Preparation of restore sample
Unless otherwise agreed, the laboratory sample is reduced at one time to obtain
the restore sample. The other half of the sample obtained by the reduction is
used for the preparation of test sample.
8.7 Preparation of test sample
The laboratory sample, after necessary crushing and grinding, is reduced into
a test sample. The minimum retention of test sample is 50 g.
9 Packaging, identification, and transport of sample
9.1 Packaging of sample
Containers or packaging bags with appropriate capacity and specifications shall
be used to hold the extracted samples. They shall be sealed; and according to
the characteristics of sample, stored under appropriate conditions. It shall
prevent any foreign impurities from contaminating the sample. It shall prevent
the sun and rain.
9.2 Identification of sample
9.2.1 The extracted sample shall be timely affixed with a unique label. The label
content shall include the sample number, name of the materials, variety or lot
number, sampling time, sampler, and any other necessary information.
9.2.2 Labels which come into direct contact with the sample must be protected
from moisture (especially for samples with high water content or samples which
need to be refrigerated or cryopreserved). The written content shall be non-
erasable, to avoid loss of relevant information.
9.3 Transport
Laboratory samples shall be delivered and transported in the shortest possible
time. The environmental conditions of transport shall be determined based on
the nature of sample. For samples with special requirements (such as samples
which need to be refrigerated), the appropriate environmental conditions must
be controlled, to avoid physical and chemical changes in the sample. Samples
without special requirements shall also be stored and transported in the dark
and dry conditions.
10 Sampling report
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.