UDC 573.6
S.E. Dromashko, M.O. Kholmetskaya, L.S. Sidor, S.O. Vdovenko,
N.N. Belko
DETECTION OF GENETICALLY MODIFIED COMPONENTS IN FOODSTUFFS: RESEARCH EXPERIENCE OF THE LABORATORY FOR GMO DETECTION AT THE NATIONAL BIOSAFETY COORDINATION CENTRE
National Co-ordination Biosafety Centre at the Institute of Genetic and Cytology of NAS of Belarus, Minsk, Belarus
В Республике Беларусь все пищевые продукты должны быть маркированы на содержание генетически модифицированных ингредиентов (ГМИ). Контроль ГМИ в Беларуси основан на детекции 35S промотора вируса мозаики цветной капусты с использованием двух методов: ПЦР + электрофореза и ПЦР в реальном времени. Мы используем метод ПЦР + электрофорез, который позволяет определять ГМИ в продуктах питания с чувствительностью 0,1 %, что достаточно для проведения качественного анализа. За пять лет проведено свыше 11 000 анализов на наличие ГМИ образцов пищевых продуктов, содержащих сою и кукурузу. Количество продукции, содержащей ГМИ, относительно невелико и в настоящее время сохраняется на уровне 1 %.
Introduction. At present a distinct rise is noted in applying new technologies associated with developing transgenic plants and production of foodstuffs on their basis. As a result of this fact, there is some probability of genetically modified ingredients (GMI) penetration into human organism. The foodstuffs, produced by using genetically modified raw materials, subject, as a rule, to more serious assessment for safety than the conventional foodstuffs. International and national legislations in the field of biosafety require talking into account of the consumer’s right to get information on application of gene engineering technologies in producing the given foodstuffs.
Main Part. Different standard requirements are used for marking products containing GMI in various countries. In particular in Russia and EU countries, no marking of genetically modified products is allowed, given the GMI content does not exceed 0.9 %. In the Republic of Belarus in conformity with the national legislation, threshold – free marking is applied and the products listed in Table 1 are subject to the control. When GMI safety is established, the principles of estimating foodstuffs, containing GMI of plant origin recommended by WHO in 2000, are used.
The aim of analyses for detecting GMI consists in qualitative and quantitative assessment of genetic elements or proteins in the given matrix peculiar to genetically modified crops and products produced from them.
Two basic methods are used in practice for GMI detection. The first method is based on revealing proteins-transgene products and the second one – on polymerase chain reaction (PCR) (PCR+electrophoresis, PCR in real time, PCR+DNA detection on biochip).
Table 1
List of food raw materials and foodstuffs subject to checking the presence of genetically modified components in the Republic of Belarus
)window.location=%27http://edu.grsu.by/cei2011/wp-content/uploads/2011/05/3.gif%27 "3")
The methods of GMI detection using protein as an analysed parameter include analysis procedures based on antibodies.
The methods, where nucleic acids are used as an analysed parameter, are based on DNA extraction from foodstuffs and on determination of the fact of its genetic modification by PCR. The methods are based on identification of recombinant DNA and are aimed at revealing regulator sequence of promoter 35S of cauliflower mosaic virus. This is due to the fact that almost all the genetically modified plants, presented now at the world foodstuffs market, contain the same DNA sequences regulating the function of the gene encoding an introduced trait, namely the promoter 35S from cauliflower mosaic virus and terminator NOS from A. tumefaciens. Two basic methods are used in the Republic of Belarus in controlling samples for the GMI content: PCR+electrophoresis in agarose gel and PCR in real time (STB GOST R 52173-2005, STB R ISO 21569:2005).
Both methods are widely practised in the Republic of Belarus. The PCR method in real time is more expensive and provides threshold sensitivity of less than 0.1%. In some cases this can become a cause of getting the so-called «pseudopositive» results, since standard samples (reference materials) are calibrated for the GMI presence with an error of no less than 0.1 %.
Fifteen experimental laboratories (6 – in the system of the Ministry of Public Health, 6 – at the State Standard, 2 – at the National Academy of Sciences and 1 – at the Ministry of Agriculture and Food) were set up in the Republic for organizing GMO control, namely:
1. Republican Scientific and Practical Centre for Hygiene.
2. Republican Centre for Hygiene, Epidemiology and Public Health.
3. Minsk Centre for Hygiene and Epidemiology.
4. Brest Regional Centre for Hygiene, Epidemiology and Public Health.
5. Gomel Regional Centre for Hygiene, Epidemiology and Public Health.
6. Mogilev Regional Centre for Hygiene, Epidemiology and Public Health.
7. Belarusian State Institute for Metrology.
8. Brest Centre for Standardization, Metrology and Certification.
9. Vitebsk Centre for Standardization, Metrology and Certification.
10. Gomel Centre for Standardization, Metrology and Certification.
11. Grodno Centre for Standardization, Metrology and Certification.
12. Mogilev Centre for Standardization, Metrology and Certification.
13. Belarusian State Veterinary Centre.
14. Scientific and Practical Centre for Food at the National Academy of Sciences of Belarus.
15. Institute of Genetics and Cytology at the National Academy of Sciences of Belarus.
The PCR+electrophoresis method is used in the Laboratory for GMO Detection (LDGMO) at the National Biosafety Co-ordination Centre. It allows GMI detection in foodstuffs with sensitivity of 0.1 % that was verified in analyzing reference materials. Appearance of «pseudopositive» results with such sensitivity is practically ruled out (in using standard reference materials). At the same time sensitivity of 0.1 % is sufficient for carrying out a qualitative analysis of samples for the GMI content.
Above 11 thousand analyses of foodstuffs containing soya and maize were made for GMI presence over the time of our laboratory existence. The results of GMI detection in foodstuffs (on order of organization and individual business owners) obtained during 2006–2010 are given in table 2.
As a result of the performed analyses, it was established that, on the average, slightly more than 1 % of products contain GMI, in an overwhelming number of cases genetically modified soya. Genetically modified maize was detected in isolated cases. Soya oil meal, semi-finished products from chicken meat, semi-finished fish products and some other products are among the products containing GMI. The highest quantity of genetically modified products was supplied in 2008 – about 2 %. In 2009 and 2010 a decrease in the quantity of such products was observed. However it is too early to draw definite conclusions of the tendency to a decrease in the quantity of GMI products: a further set of statistically significant data is required. The results obtained by LDGMO will be taken into consideration in improving and harmonizing legislation in the field of biosafety and protection of consumer’s rights.
Table 2
Data on testing foodstuffs for GMI content in LDGMO during 2006–2010
.
)window.location=%27http://edu.grsu.by/cei2011/wp-content/uploads/2011/05/31.gif%27 "3")
Besides, in 2009 LDGMO conducted monitoring for the content of genetically modified components in foodstuffs on order of Belarusian State Institute for Metrology. The goal of such monitoring was to obtain results of tests in some groups of products for possible extension of the list of products controlled for the GMI content and to establish a threshold value of the GMI content with excess of which products are subject to obligatory marking. The results of monitoring have shown the absence of recombinant DNA in all the samples studied and it was concluded that it was not necessary to analyse the given products for the GMI content.
Conclusion. On the whole, by the results of our investigations one can conclude that the quantity of products containing GMI is relatively small and at present remains at the level of 1 %.
In the Republic of Belarus all food products must be marked for the content of genetically modified ingredients (GMI). GMI-control in Belarus is based on the detection of 35S promoter of cauliflower mosaic virus with application of two methods: PCR plus electrophoresis and PCR in real time. We tested more than 11 000 analyses of food samples, containing soy-bean and maize during past five years. The quantity of products containing GMI is relatively small and at present remains at the level of 1 %.
