**hello all, things i post in blog are the summarise form :) for more detailed info please refer to the research file which i had posted in file exchange or the references given :)
Detection of Genetically Modified Food. ( DETECT DNA in GM food )
Two basic methods:
1) test for food product of a transgene which is a protein.
~ ELISA (Enzyme Linked ImmunoSorbent Assay)
~ level of protein measured
~ protein is bind to antibodies which is link to an enzymes.
~ specific protein detected when the protein reacts which the substrate.
~ react between antibodies and protein inserted
~ can be detected by colour change through quantative results.
~ not effctive on processed food such as canned food (high temperature teatment may destroy the protein. )
~ cheaper than DNA
~ save time
~ less specific than ELISA
~ less sensitive
~ gives qualitative and quantitative results.
2) test for presence of DNA from a transgene or gene cassette.
~ polymerase chain reaction (PCR) test to detect foreign DNA in genetically modified food [MORE COMMONLY USE]
[ for DNA isolation, PCR DNA Amplification and gel electrophoresis analysis, please refer to the reference listed below post from Madison Area Technical Collegue , silde 12 to silde 14 ] :))
~ results are obtained through gel electrophoresis
~ more expensive
~ more time needed
~ ineffective in detecting high heat treatment processed GM food, refine oil from GM crops, however can be over come by Real Time PCR that uses fluorescence to monitor the PCR amplification process
~ detectable at low levels
~ more specific than ELISA
~ more sensitive
~ produce qualitative answer, only get quantitive results if real tiem PCR is used
Polymerase Chain Reaction
Quantitative detection (QPCR): test for amount of GMO present
- quantitative real-time PCR (QRT-PCR) is the most effective way for GMO detection.
- To quantify the amount of amplified product, fluorescent dyes such as SYBR Green I or fluorophore containing DNA probes are being used.
- results are analyze by Gel Electrophresis of DNA. QRT-PCR
Qualitative detection: show whether GMO are present but not the amount
- Test by Q-PCR or multiplex PCRResult can be analysed by gel electrophoresis.
Methods of Genetically Modifying Food. ( INTRODUCE DNA in GM food )
~ introducing new genetic material into host
Three main methods to introduce foreign DNA:
1) Physcial Methods (particle gun and electroporation)
2) Chemical Methods (polyethyleneglycol and calcium chloride)
3) Biological Vectors (Ti-plasmid from Agrobacterium) [most commonly used] :
~ transgene ( DNA to be transferred ) introduced with second vector which is
~ the Ti plasmid of Agrobacterium tumefaciens
~ for transgene to work effectively in its new host, it had to be controlled by promoter and terminator sequence which is known as gene cassette when grouped.
~ common terminator: Ti plasmid in Agrobacterium tumefaciens
~ common promoter: CaMV35S promoter
source taken from:
- Madison Area Technical Collegue (2002). Chapter 5. PCR-Based Detection of Genetically Modified Food. Retrieved on 25 June 2008 from: http://ucbiotech.org/edu/edu_aids/5-brandner.pdf
- Asian Food information Centre. (2004). Detecting Genetically Modified Food. Easier said than done. Retrieved on 21 June 2008 from: http://www.afic.org/Detecting%20Genetically%20Modified%20Foods%20-%20Easier%20said%20than%20done.htm
Some points found on GMF in Singapore.
- GMF are not halal due to animals products are also being used to genetically modified.
- research shows that GM crops are halal. however if the gene inserted is from animals DNA., it is not certified as halal.
- In Singapore, products such as corn, canola oil, soy bean are genetically modified.
- Labeling of GM food in Singapore is not compulsory
- So far there is no legalization and guidelines for the labeling of GMF.
- GM rice are not grown commercially in Singapore.
- The price of GM seed is twice of the normal seed.
Source taken from:
- GMAC Singapore. Singapore press holdings. (2008). GM crops a viable option for food crisis? Retrieved on 15 June 2008, from http://www.gmac.gov.sg/News/2008/2008_05_12.html
- GMAC Singapore. (2007). Genetically Modified Food. Retrieved on 15 June 2008, from: http://www.gmac.gov.sg/Index_FAQs_Genetically_Modified_Foods.html#six [ also state which are the countries which approved GMF and what are the crops that are approved plus some other good info abt GM ]
9:35 PM
Hey, this website shows ethical issues and questions linked to GM food, the laws in different countries and etc:
- BIONET Future Food. Rights and Wrongs (2002). Retrieved on 10 June 2008 from: http://www.bionetonline.org/English/Content/ff_eth.htm
Controversial issues:
Examples of controversial issues include
- Safety : allergens that are present, transferring of genes to other unintended crops and some other factors that cause unknown effects which are harmful to consumers.
- Ethics : damaging the natural characteristics of the natural food such as intrinsic factors, damaging nature and disagreement with plants genes that contains animals genes and vice versa.
- Labeling : not all countries required compulsory labeling of GM food.
- Environmental concerns : genes inserted may be transferred to soil which result in the next crop planted serving the intended purpose of the gene which would result in the crop being genetic modified unknowingly.
- Health concerns : unknown effects for consumption of GM food due to genetically modified crop
- Religious concerns : GM crops are not certified as halal as it is not consider wholesome and animals genes maybe inserted into GM for specific purposes that may not be halal. This is a concern for all the muslims which could only consume food that are halal.
Safety Assessment of GM Food (before GM food are being sold out in the market) :
GM food are being accessed for safety before it can be sold in the market. Accessing GM plants required a few important factors such as
- toxicity,
- allergenicity
- nutritional value
Some other factors of safety assessment would include
- source,
- identity,
- effects of processing,
- recombinant DNA,
- whether there is any effects of the gene inserted.
Toxins :
- should not be present in GM food or it should be present within the acceptable range of safety.
Allergens :
- important to be accessed
- as the presence of allergens in some food may cause serious effect in some consumers.
- For example, if the gene of peanuts is inserted into corn, people who are allergic to peanut would be allergic to the genetically modified corn. In this case product must be labeled that it contains traces of nuts meeting the safety of consumers.
Nutrient composition :
- likely to change
- possibility that consumer may lack of certain important nutrients
- may lead to unbalance nutrition or malnutrition.
Product Labelling and Consumer Rights:
consumers had the right to know the nature of the products that they had consume, thus labelling is an important factor.
( GMF labelling had to maintain consumers right ) GM labelling should conform to the 3 principles stated:
1) provide sufficient information,
2)consumer protection from misunderstanding
3)potential risk.
~ Labelling provide a list of ingredients.
~ Ensures that food are safe for consumers.
~ There is no standard of how GM food is to be labelled currently however multilateral guidelines are now being developed by Codex Alimentarius.
~ labelling gives a information to consumer that is non misleading, easy to understand and facts about GMF. This can ensure fair practices in food trade and thus safety.
( making sure that what had been added in the product even it is not genetically modified is also being labelled )
Source taken from:
- Institute of Food Technologists and International Union of Food Science and Technology. The World of Food Science. (2007). Labelling of Food Containing GMOs: a Thailand Perspective. Retrieved on 17 June 2008. from: http://69.36.46.53/cms/?pid=1001115
- Consumers Protection Comission, Executive Yuan. Introduction to Genetically Modified Food. (GMF). Retrieved on 26 June 2008 from: http://www.cpc.gov.tw/en/index.asp?pagenumber=20
- Human Genome Project Information. Genetically Modified Food and Organisms.
Retrieved on 17 June 2008 from: http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml
some info taken from this website ( RECOMMENDED ) shows clear infomation of safety assessment, how GMO are being developed and the processes. toxins in GM food, labelling, regulations and a lot more. (:
- Food Standards. Austraila New Zealand. (2005). GM Foods. Safety Assessment of Genetically Modified Foods. Retrieved on 9 June 2008 from: http://www.foodstandards.gov.au/_srcfiles/GM%20Foods_text_pp_final.pdf
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GENETICALLY MODIFIED FOOD.
Some examples of GM foods are Soy beans, corns, rape plants, sweet corn, golden rice, tomatoes, sugar cane, potatoes, strawberries, flax, and apples.
Examples of the purpose of modifying some of the foods are:
Soya beans - resistant to crop spray
Sweet corn - resistant to crop spray and produce insecticide
Rape plants - resistant to crop spray and does not produce pollen(thus it is not able to pollinate other plants)
There a both advantages and disadvantages of using GM food.
Here are some of the advantages and disadvantages of GM food.
Advantages:
- Increased and better yield can solve malnutrition and solve many world hunger/ feed the world.
- Less pesticide and herbicides will be used
- Pest resistance and herbicides tolerance
- Disease resistance
- Increase tolerance of crops such as bad weather eg: drought, cold tolerance
- More Nutritional value
- Pharmaceuticals
- Phytoremedication
- More efficient use of land
- Better texture and flavour
Disadvantages:
- GM food may not be accepted by all people compared to natural crops.
-Human health risks: allergic and unknown effects. May cause cancer or other illness.
- Environmental hazards: GM crops that are planted beside natural crops may cause genes to cross over to natural crops.
- Economic concerns: costly and lengthy process
- May cause toxic to soil.
- Alter nutrients compositions
- May increase allergens and toxins in food
Genetic engineered food can be used to improve yield. Genetic engineering is the transfer of DNA from organisms of one species into organisms of a different species.
source taken from:
- Church of Scotlands. (2001).Genetically Modified Foods: Pro and Cons.Retrieved on 8 June 2008 from: http://www.srtp.org.uk/gmfood1.htm
- Proquest. (2008). Genetically Modified Foods: Harmful or Helpful? Retrieved on 3 June 2008 from: http://www.csa.com/discoveryguides/gmfood/overview.php
Bacillus Thuringiensis
- We had chosen corn as the raw materials to produce flour and starch.
- DNA gene of the bacteria Bacillus thuringiensis(Bt) is used to transfer into corn.
- Bt can make the crops produce a toxin in all its tissues
- crystal proteins are produced by it are toxin to some insects
- able to kill the insects that feed on corn.
- bacterium that could be found commonly in soil.
- gives a greater yield of 6 to 8 percent compared to the natural crops.
- Some disadvantage :
the present of the pollen produce form the genetic engineered corn will also harm other insects such as butterflies which is not the intended purposes and soil microorganism may also be damaged. - GM plants with Bt have been genetically modified to contain one or more of the genes from Bt that produce these crystal proteins
- The modified plants produce one or more types of Bt crystal protein (in their leaves, stems, roots and other plant tissue), and susceptible insects that eat the plant are poisoned.
- Most of the crystal proteins produced by Bt are toxic to particular groups of insects (either butterflies and moths, beetles or flies). The proteins are not toxic to any other insects or living organisms, and are harmless to humans.
source taken from:
Nina E.Redman. Food Safety. (2007) ABC-CLIO Inc. Second edition.
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