Welcome to our Food Safety blog =).

Created: 10 April 2010
Leader: Lynnette Heng
Members: Lorelle Ang
Soh Chin Yi
Goh Ai Ting
Li Yuen Ying

Lynnette: KK Hospital- Dietitian
Chin Yi: Gardenia- R&D
Ai Ting: Singapore Sports Council- Nutritionist
Yuen Ying: KH Roberts- lab assistant
Lorelle: OSIP (China)

credits to:
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During the research, I came to know more about HACCP and GM Food. I did not realise that there are many conflicts between authorities for example the labelling rights and howit will affect trades. Working on the packages made me realise that working in addition to doing research for the subject is not easy as a whole day of work use up mpst of our time that can be use to do researching. However, if the mind is set to do, then it can be done.

Soh Chin Yi
As package 1 was involved with CCP decision and Product Specification, an area that we were familiar with from the experience obtained from FPQA and FPQAP, online discussion was comparatively less challenging compared to Package 2 where it involved a new area explored mainly on the isolation methods as well as toxin detection methods. However, our group still made it a point to meet up in school on Saturdays as we need to come up with a common agreement on matters like CCP Decision. Although it is a tiresome fact that after slogging out during the weekdays at each of our various Internship locations, meeting up to clarify doubts and uncertainty where all of our members are present gave us all a clearer picture of where we are headed in the projects. Initially as we are new to using the online discussion board, we merely used it as a platform for deciding a time and place for our meeting. However, as the workload increased and we generally get more accustomed to online discussion, our usage for the online discussion board increased. Personally I still disliked the fact that we have to check the blackboard frequently for updates, for if we do not, we will lose track of how the group have progressed.

As for self directed learning, it forms a greater portion in Package 2. I find it quite a difficult task not from searching for resources but to sift out the useful information for our project as most of the raw information found included many figures, short forms, scientific annotations and tables which required me to reread the same short paragraph to get an idea of what the writer was trying to bring forth. The more challenging ones are the toxin detection methods where their manner of explaining the principles and science behind how they carry out the tests are not easily comprehensible.

For package one, the knowledge and skills that I have learnt from FPQA and FPQAP such as identifying critical control point, extrinsic and intrinsic factors, product specification and HACCP plan were applied. This time, I have learnt about what product recall is and and better understanding on how to handle food poisoning/ foodborne illness. Initially we were all not used to it and had faced some difficulties in communicating on the discussion board. Hence, we arranged meeting a few times in school to complete some parts of this package.

From package two, I have a better understanding on what genetic modification is about, the advantages and disadvantages and techniques to detect foodborne pathogens. As compared to package one, I find this to be more challenging because we do not have much background knowledge on genetic modified foods.

As I am now more used to online discussion, there were a lot of self-directed learning and sharing done between my group mates and I on the discussion board. As compared to package one, I felt that I have make use of the discussion board more frequently because I realized that it is a efficient way to share our research. This time, there were no meetings face to face at all, other than looking for package two related books.

After package two was launched, I realized that we could learn more from each other from the online discussion board. By posting websites or files that were found by each of us, we can actually have a better understanding for the problem statement rather than just reading through what they have summarized from websites or files. Also, with the use of online discussion board, we do not have to fix a time or day for discussion of the package as we just needed to post what we have found and discussion can be done on the discussion board itself.

Hence, I felt that online communication is a useful skill that I have learnt. It enables my group mates and I to communicate and share our findings efficiently and effectively.

For package 1, I was still in school for the launch. Therefore, I was still able to participate quite a far bit in the FILA template and also the delegation of the tasks. However, as I am having my internship overseas, in China, I left Singapore 2 weeks after the launch. What was worse was that there was no internet connection here until about 1 week later. Therefore, I could not contact my group members or post anything up on black board. I felt really bad because by the time my internet was fixed and I could post things up on ole-bb, a lot of posts and researches have been done by my other team members. Therefore, I still tried to help out as much as I can by doing a larger share of the report and also helping out in research for the other members as well as my own part.

For package 2, it was worse. I was not able to be present at the launch. And therefore, unable to be present for the delegation and the rough FILA template draft. This made me feel really bad and guilty that I was not able to be present at the brainstorming session. However, I looked through the FILA draft template after it was posted on ole-bb and added for things that can be included in the blog/report. This time, my group members gave me a more crucial part to play in the research because I complained to them the other time that for package 1 I did not help much at all.

As this is a online project, teamwork is not much of an issue as we seldom have actual face to face contact with each other and in my case none at all. Therefore, there were little conflicts. However, because it is an online subject, it can cause one to be more lazy and complacent. And it is apparent that there are some who post more things online than others. And the thing with online subject is that because there is very little accountability factor, it is hard to persuade and make that person who is lacking to improve themself.

Also, one thing that I did not like was that my group did not have online discussion e.g on msn. Which leaves me out quite a bit as they usually meet in school on weekends instead. Although I have suggested quite a few times to them to have an online discussion, however, they prefer to have a face to face meeting in school as it is more convenient and efficient.

The difficulty level of the project is not hard as most of the researches can be done quite fast now with the help of internet. However, there are some parts which still needs to be done by researching the books in the library like the toxins and pathogens part. However, the one hard part about the project is the ability to sift through the plenty of information that can be found and make sure that the correct and reliable one is used. Also, with the plenty of information that can be obtained, it makes it hard to compress it to 10 pages of the report.

What I have learnt from this online subject is that I still prefer conventional projects where there are meetings face to face rather than through the computer/internet. However, it is quite useful as next time in the actual working world, not everything can be done face to face as sometimes clients are overseas or another branch overseas; just like the situation I am in right now where all my fellow team members are in Singapore and I in China.

Throughout our Food Safety Project, we encountered problems such as difficulty contacting group mates that are away from Singapore for OSIP & also difficulty with having meetings online. Not only was it difficult to understand each other using the internet, it was also difficult to have a fix date & time where we can all be online to have the meeting. But through this tough period, we have improved our team skills by depending on one another while taking responsibility in our own task. We would make sure we do our part in the project. And if there’s any problem, we would consult with one another or even ask for help to finish it up, especially Package 2 as this package is mainly about GM Food & Toxins which are very new to us. Moreover, when we search thorugh the internet, much of the research state that GM Food are still undergoing researching. Thus searching for GM Food prove us lots of difficulty. However, with the help from my group mates, we manage to find much informations we needed.

We also tried our best to finish our task as early as possible to avoid dragging down the other group mates. And when there are problems that we all couldn’t understand, we would find a time where some of us would go to the library together to search for information & also consult our teacher. Although some of us is so busy with their stuff, everyone still try their best to make some time so that we can go to the library together to search for informations.

We would also make sure to remind each other of due dates & meeting dates to avoid having any one not passing up anything or anyone missing the group meetings. We also tried our best to keep in contact with our group mate that went for OSIP to keep her inform of the stuff we are doing & what she can to help.

Bacillus cereus is a bacterial that tends to grow in starchy food. Since potato is a starchy food, there may be growth of Bacillus cereus on the potatoes. Bacillus cereus is also commonly found in soil, air & water. Thus, if the potatoes are grown on contaminated soil or uses contaminated water, Bacillus cereus may transfer from these sources to the plant itself. Moreover, Bacillus cereus is a spore-forming microorganism. Therefore, there might be possibility that the pathogen survive even after heating process. (European Bioinfomatics Institute, 2010; MicrobiologyBytes, 2007)

• MicrobiologyBytes. (2007). Bacillus cereus. Retrieved on 6th July 2010, from MicrobiologyBytes. Website: http://www.microbiologybytes.com/video/Bcereus.html

GLYCOALKALOIDS
-naturally occurs in potatoes and are pest resistant.
-found in mainly potato sprouts & the peel of potatoes that taste bitter. but usually found low in levels.
-produced by the plant in response to stress such as microorganisms, UV light, and damage such as bruising.
-Concentration of toxin may vary because of fungal or bacterial infection & usually increase in response to wounding, as a defense mechanism against potential diseases.
-Amount of toxins produce also depends on the type of potato and their growing conditions. -glycoalkaloid poisoning can cause severe stomach ache and even death as it is an inhibitor of choline esterase that can cause hemorrhagic damage to the gastrointestinal tract as well as to the retina. however, this is very unlikely
-glycoalkaloids are not destroyed by cooking temperatures as its decomposition temperature is about 243ºC
-it is very important that the sprout of the potato, any greening due to sunlight exposure or damage parts of the potato and the skin of the potato are remove adequately before cooking to prevent consumption of such toxins by the consumers.
-it is recommended that potatoes are to be stored in dark, cook and dry places, as levels of glycoalkaloids increases when the potatoes are exposed to bright light for long period of time and storage under 10ºC. (New Zealand Food Safety Authority, n.d.; S.S. Deshpande, 2002; FAO Corporate Document Repository, n.d.)

ARSENIC
-occurs in our food in both organic and inorganic forms.
-groundwater that are from areas with geothermal activity and rocks that are rich with arsenic will contain extremely high levels of arsenic.
-Arsenic is also naturally present in all soils, thus the arsenic content of plants is usually determined by the arsenic content of the soil, water, air, fertilizers and other chemicals.
-Arsenic level in the plant can also be affect by the use of pesticides that may contain arsenic.
-If arsenic containing water is being use accidently to water the plants, the potatoes may contain high levels of arsenic that will increase the risk of consumers getting cancers. (Zealand Food Safety Authority, n.d.)

AFLATOXIN
-a mycotoxin that has been found in many foods of animal & plant origin.
-produced by 4 species of Aspergillus: A. flavus, A. parasiticus, A. nomius & A. pseudotamarii that contain metabolites that have been implicated in carcinogenicity, mutagenicity, teratogenicity, hepatoxicity & aflatoxicosis.
-Aflatoxicosis is the major syndrome associated with aflatoxins and the liver is the primary target of the toxin.
-Moderate to high consumption of the toxin will fatty, pale & decolorized livers, derangement of normal blood clotting mechanisms, resulting in hemorrhages, reduction in total serum proteins of the liver, accumulation of blood in the gastrointestinal canal, glomerular nephritis & lung congestion. (Heredia, N., Wesley, I., Garcia, S., 2009)

PROTEINASE INHIBITOR
-protects the potato against insects and microorganisms but are not toxic because they are destroyed by heat.
-Lectins or haemogglutenins are also present in potato. These toxins are capable of agglutinating the erythrocytes of humans, but are of no significant issue as they can be destroy by heat. Thus, it is important that the potatoes are adequately cooked. (FAO Corporate Document Repository, n.d.)

• New Zealand Food Safety Authority. (n.d.). Arsenic and the food we eat. Retrieved on 1st June 2010, from NZFSA. Website: http://www.nzfsa.govt.nz/consumers/chemicals-nutrients-additives-and-toxins/arsenic/
• Heredia, N., Wesley, I., Garcia, S. (2009). Microbiological Safe Foods. U.S.A., New jersey: John Wiley Sons, Inc.
• FAO Corporate Document Repository. (n.d.).Toxic substances and antinutritional factors. Retrieved on 1st July 2010, from FAO. Website: http://www.fao.org/docrep/T0207E/T0207E08.htm#Potato

modification proces

- Based bacterial transformation system was used to modify the potatoes, where cells from the potato parental line were infused with a specifically constructed plasmid vector carried into each plant cell by the bacterial system.
-The vector carries the genetic code for resistance to the pests Colorado Potato Beetle (cry3A) and Potato Virus Y (PVYcp), and a marker gene for plant selection (nptII ). The Agrobacterium used in the transformation process is no longer considered a plant pest threat.
-The Agrobacterium containing the vector was added to potato stem sections into culture dishes and then transferred into the genome of individual potato cells thereby allowing selection on neomycin-containing media. Subsequently, the potato tissues were treated to regenerate the transgenic cells into shoots and tested for CPB and PVY resistance.


CRY3A gene and its encoded CRY3A protein
-Cry3A gene was isolated from the DNA of a strain of Bacillus thuriengensis subsp. tenebrionis (Btt).
-Upon ingestion it will disrupt cause the gut epithelium of the Colorado beetle to rupture causing the pest to die without harming the potato plant.


PVYcp gene
-PVY capsid protein gene (PVYcp) was obtained from a PVY strain isolated from potato.
-The gene sequence engineered into NewLeaf Y potato is identical to that of the native viral gene, except for a synthesized start codon.
-Studies conducted show that mRNA encoding for PVY proteins is produced in NewLeaf Y potato plants at levels well below that occurring in potato plants naturally infected with PVY.

marker gene NPTII
-To facilitate this process, a selectable marker gene, NPTII, and selective agent, kanamycin are incorporated into the growing media.
-cells that are selected for plant generation contains the NPTII and CRY3A genes.
-NPTII gene functions as a dominant selectable marker in the initial laboratory stages of plant cell selection after transformation.
-NPTII enzyme uses ATP to phosphorylate kanamycin to inactivate aminoglycoside antibiotics in the growth media to prevent them from killing the cells that produces NPTII.

(Safety Assessment of NewLeaf Y Potatoes Protected Against Colorado Potato Beetle and Infection by Potato Virus Y Causing Rugose Mosaic, 2002)
(http://www.agbios.com/docroot/decdocs/02-269-004.pdf)

the GM potato that we are going to use as an example is The NewLeaf Y potatoes that have been approved and released in the market already since 1998 by Monsanto Company. NewLeaf Y potatoes were developed for resistance to the pests Colorado Potato Beetle (cry3A, the gene that produces a protein toxic only to target insects, isolated from the bacteria Bacillus thuringensis tenebrionis, Btt)
(Kaniewski, W.K. & Thomas, P.E. 2004)


(naturemark,2002)

http://www.agbioforum.org/v7n12/v7n12a08-kaniewski.htm
http://www.naturemark.com/pages/TOP_SUS_Links.html

DNA Hybridization

The identification of bacteria by DNA probe hybridization methods is based on the presence or absence of particular genes. The physical basis for gene probe tests arises from the structure of DNA molecules themselves.

DNA composes of two strands of nucleotide polymers that form a double helix held together by hydrogen bonds. The hydrogen bonds holding the strands together can usually be broken by raising the pH above 12 or the temperature above 95°C. As a result, a single-stranded molecule is achieved and the DNA is considered denatured. At a lowered pH or temperature, the hydrogen bonds are reestablished, reforming double-stranded DNA. The source of the DNA strands is inconsequential as long as the strands are complementary. If the strands of the double helix are from different sources, the molecules are called hybrids and the process is termed hybridization.

A gene probe composes of double-stranded DNA. It has either an entire gene or a fragment of a gene with a known function. The short pieces of single-stranded DNA can be synthesized based on the nucleotide sequence of the known gene, commonly known as oligonucleotides. Both natural and synthetic oligonucleotides are used to detect complementary DNA or RNA targets in samples.

Double-stranded DNA probes are required to be denatured before the hybridization reaction beginsThe target nucleic acids are denatured by high temperature or high pH, after which labeled gene probe is added. If the target nucleic acid in the sample contains the same nucleotide sequence as that of the gene probe, the probe will form hydrogen bonds with the target. The bound label signals the presence of probe-target complexes.

The oligonucleotide of known sequence, derived from gene of known function, is end-labeled with radioactivity. DNA probe is allowed to incubate with DNA extracted from a sample. If target DNA contains sequences complementary to those of the probe, the probe and its radioactive label will bind with the sample DNA.

Colony Hybridization

DNA hybridization tests may be performed in many ways. One way is by the colony hybridization assay.

Firstly, a portion of a homogenized food is spread-plated on an appropriate agar. After incubation, the colonial pattern is transferred to a solid support (a membrane or paper filter) by pressing the support onto the agar surface. The cells are then lysed by high pH and temperature, which denatures and attaches the DNA to the support. The solid support with the attached target DNA is incubated with a labeled probe.

The radioactive probe DNA that is bound to the target on the support is often detected by autoradiography. Radioactive decays expose the X-ray film, which is placed over the support. When developed, black spots appear where cells are harboring the same gene as the probe.

If an enzyme-labeled probe is used, a chromogenic substrate is added. A colored spot will develop if the probe-associated enzyme is present. Each spot represents a bacterial colony that has arisen from a single cell.

The number of cells harboring the target gene in the original sample can be calculated by multiplying the number of spots by the dilution factor.

Source:

U.S. Food and Drug Administration. (2001, January). Identification of Foodborne Bacterial Pathogens By Gene Probes. website:
http://www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManualBAM/ucm072659.htm

THIN LAYER CHROMATOGRAPHY


How does thin layer chromatography work?
Chromatography all have a stationary phase (a solid, or a liquid supported on a solid) and a mobile phase (a liquid or a gas). The mobile phase flows through the stationary phase and carries the components of the mixture with it. Different components travel at different rates.

Thin layer chromatography is done exactly as it says - using a thin, uniform layer of silica gel or alumina coated onto a piece of glass, metal or rigid plastic.
The silica gel (or the alumina) is the stationary phase. The stationary phase for thin layer chromatography also often contains a substance which fluoresces in UV light. The mobile phase is a suitable liquid solvent or mixture of solvents.
The stationary phase - silica gel
Silica gel is a form of silicon dioxide (silica). The silicon atoms are joined via oxygen atoms in a giant covalent structure. However, at the surface of the silica gel, the silicon atoms are attached to -OH groups.
So, at the surface of the silica gel you have Si-O-H bonds instead of Si-O-Si bonds. The diagram shows a small part of the silica surface.




The surface of the silica gel is very polar and, because of the -OH groups, can form hydrogen bonds with suitable compounds around it as well as van der Waals dispersion forces and dipole-dipole attractions.
The other commonly used stationary phase is alumina - aluminium oxide. The aluminium atoms on the surface of this also have -OH groups attached.
What separates the compounds as a chromatogram develops?
As the solvent begins to soak up the plate, it first dissolves the compounds in the spot that you have put on the base line. The compounds present will then tend to get carried up the chromatography plate as the solvent continues to move upwards.
How fast the compounds get carried up the plate depends on two things:
• How soluble the compound is in the solvent. This will depend on how much attraction there is between the molecules of the compound and those of the solvent.
• How much the compound sticks (known as adsorption) to the stationary phase - the silica gel, for example. This will depend on how much attraction there is between the molecules of the compound and the silica gel.

References:
http://www.chemguide.co.uk/analysis/chromatography/thinlayer.html

Johns H.(2008). Current Protocols in Nucleic Acid Chemistry. Thin‐Layer Chromatography. Retrieved from: http://www.currentprotocols.com/protocol/nca03d

2. DNA-Based

• Southern blot
Southern blotting is designed to locate a particular sequence of DNA within a large, complex sample of DNA. For example, Southern Blotting can locate a single specific gene within an entire genome
http://www.biochem.arizona.edu/classes/bioc471/pages/Lecture2/Lecture2.html

• Quantitative end-point PCR
It is a crucial aspect of analysis of GMOs in food is quantitation, because maximum limits of GMOs in foods are the basis for labeling in the EU .Therefore, more quantitative PCR approaches were needed. PCR was shown to be quantitative if an internal DNA standard was coamplified with target DNA. In systems such as the quantitative-competitive (QC)-PCR method (Fig. 3), the presence of PCR inhibitors will be noticed immediately because the amplification of both internal standard and target DNA will be simultaneously affected. QC-PCR consists of four steps: (1) coamplification of standard- and target-DNA in the same reaction tube; (2) separation of the products by anappropriate method, such as agarose gel electrophoresis and staining the gel by ethidium bromide; (3) analysis of the gel densitometrically; and (4) estimation of the relative amounts of target and standard DNA by regression analysis.

[Farid E.Ahmed.Detection of genetically modified organisms in foods. (2002)]

1. Protein-Based

Immunoassay is the current method for detection and quantification of ‘new proteins introduced through genetic modulation of plants. The crucial component of an immunoassay is an antibody with high specificity and affinity for the target molecule. Immunoassays can be rendered highly specific and samples often need only a simple preparation before being analyzed. However, Protein-Based methods can only be applied if a new protein is expressed in GMO. Using the antisense or sense technology to suppress or overexpress the transcription/translation of a gene originated from plants does not result in a new protein. Even so, newly expressed proteins are usually varied in expression levels in different plant tissues. Thus the new protein may be express in very low levels, which may be below the detection limit.

Western Blot

It is a highly specific test method that provides qualitative results suitable for determining whether a sample contains the target protein below or above a predetermined threshold level. It is particularly useful for the analysis of insoluble protein. The detection limits of western blots vary between 0.1 and 1%. Sensitivity is dependent on the affinity level and level of expression of the protein in the plant.

Enzyme-Linked Immunosorbent Assay (ELISA)

it is a method to detect the presence of the specific protein that the genetically modified DNA produces in the plant.
Antibodies are used to react with specific proteins produced by the GMO. These are coupled to an enzyme, which catalyzes a color-reaction with a substrate. Positive, negative, and quantitative results are determined by detecting the color change in the reaction.
there are different types of the ELISA method used for GMO detection.
One type is known as “strip test” which uses lateral flow strips. And the results can be delivered in two to five minutes. Strip tests used when a rapid assessment to determine the presence or absence of GMOs is needed.
Another type of the ELISA test, the "plate test," provides indication of the quantity of the tested sample that is the GMO. The higher the amount of protein present, the more intense the color will be. The plate test can take two to four hours and is more laborious, and costly than the strip test.
this method is good because it a cheap and fast technique. however, ELISA tests have limitation in detecting GMOs in processed foods as heat processes denature the proteins, making detection of proteins difficult.

Figure 1. ELISA strip or "dipstick" tests can detect GMOs in grain and seed in three to five minutes.
Figure 2. ELISA "plate tests" can provide some quantitative assessment of the GMO present.

[Karthik Raman. (n.d.). Retrieved on 7th July 2010. Website: http://proline.physics.iisc.ernet.in/home/images/e/ee/Karthik-DNA-GMO.pdf]

[P. Markoulatos, N. Siafakas, A. Ppathoma, E. Nerantzis, B. Betzious, V. Dourtoglou & M. Moncany. (2004). Qualitative & Quantitive Detection of Protein & Genetically Modified Food. Retrieved on 7th July 2010, PP. 275-296, 2004]

[Eurofins Gene Scan. (2009, May 28). Genetically Modified Organisms (GMO) Technical Sheet. Retrieved from www.gmotesting.com/docs/GMO_Technical_Sheet.pdf]

[Thomison, P. R., & Loux, M. M. (2001). Commonly Used Methods for Detecting GMOs in Grain Crops. Retrieved July 10, 2010, from Ohio State University Extension fact Sheet, website: http://ohioline.osu.edu/agf-fact/0149.html]

• Karthik Raman. (n.d.). Retrieved on 7th July 2010. Website: http://proline.physics.iisc.ernet.in/home/images/e/ee/Karthik-DNA-GMO.pdf

Negative effects on human health:
- The gene (snowdrop flower lecitin) used for the GM potatoes is toxic to mammals
-GM potatoes are 20% lower in protein than the unmodified potatoes
-Allergens could be transferred from other foods/ sources into GM foods.
-E.g. from animal sources to GM foods
-Consumption of GM foods that are antibiotic-resistant can reduce effectiveness of antibiotics and increase chances of human infectious diseases.
- Some research also found that GM foods could post negative health effects to human
E.g. potential acute or chronic health risks

Cross-breeding (environmental)
-Crossbreeding between GM crops and surrounding vegetation could result in weeds developing resistance to herbicides
- Usage of herbicides will increase → soil and water contamination

Pesticide resistant insects (environmental)
-Production of natural toxin by GM crops could encourage the evolution of pesticides-resistant insects
→ Minimize the effectiveness of pesticides

Biodiversity (environmental)
- Cultivation of GM crops on a large scale
→ Affect the biodiversity, the balance of wildlife and the environment.

• Santaniello, V., Evenson, R.E., & Zilberman, D. (2002). Market Development For Genetically Modified Foods.
  United Kingdom, Wallingford: CABI publishing pg 196. Website: http://books.google.com.sg/books?id=7YtgexvS8RQC&pg=PA196&dq=genetically+modified+foods-+potatoes&hl=en&ei=-cEHTLqsAY_CrAf9m-WAAQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCwQ6AEwAA#v=onepage&q=genetically%20modified%20foods-%20potatoes&f=false
• Thomson, J.A. (2006). GM Crops: The Impact and The Potential.
  Austrialia, VIC : Collingwood pg 83. Website: http://books.google.com.sg/books?id=Qa9H61VhyykC&pg=PA83&dq=genetically+modified+potatoes&hl=en&ei=yXYGTNWsJJC-rAfv7di-DA&sa=X&oi=book_result&ct=result&resnum=6&ved=0CD8Q6AEwBQ#v=onepage&q=genetically%20modified%20potatoes&f=false

Environmental activists, religious organizations, public interest groups, professional associations and other scientists and government officials have all raised concerns about GM foods, and criticized agribusiness for pursuing profit without concern for potential hazards, and the government for failing to exercise adequate regulatory oversight. It seems that everyone has a strong opinion about GM foods. Even the Vatican19 and the Prince of Wales have expressed their opinions. Most concerns about GM foods fall into three categories: environmental hazards, human health risks, and economic concerns.

Environmental hazards
Unintended harm to other organisms Last year a laboratory study was published in Nature21 showing that pollen from B.t. corn caused high mortality rates in monarch butterfly caterpillars. Monarch caterpillars consume milkweed plants, not corn, but the fear is that if pollen from B.t. corn is blown by the wind onto milkweed plants in neighboring fields, the caterpillars could eat the pollen and perish. Although the Nature study was not conducted under natural field conditions, the results seemed to support this viewpoint. Unfortunately, B.t. toxins kill many species of insect larvae indiscriminately; it is not possible to design a B.t. toxin that would only kill crop-damaging pests and remain harmless to all other insects. This study is being reexamined by the USDA, the U.S. Environmental Protection Agency (EPA) and other non-government research groups, and preliminary data from new studies suggests that the original study may have been flawed. This topic is the subject of acrimonious debate, and both sides of the argument are defending their data vigorously. Currently, there is no agreement about the results of these studies, and the potential risk of harm to non-target organisms will need to be evaluated further.

Reduced effectiveness of pesticides Just as some populations of mosquitoes developed resistance to the now-banned pesticide DDT, many people are concerned that insects will become resistant to B.t. or other crops that have been genetically-modified to produce their own pesticides.

Gene transfer to non-target species Another concern is that crop plants engineered for herbicide tolerance and weeds will cross-breed, resulting in the transfer of the herbicide resistance genes from the crops into the weeds. These "superweeds" would then be herbicide tolerant as well. Other introduced genes may cross over into non-modified crops planted next to GM crops. The possibility of interbreeding is shown by the defense of farmers against lawsuits filed by Monsanto. The company has filed patent infringement lawsuits against farmers who may have harvested GM crops. Monsanto claims that the farmers obtained Monsanto-licensed GM seeds from an unknown source and did not pay royalties to Monsanto. The farmers claim that their unmodified crops were cross-pollinated from someone else's GM crops planted a field or two away. More investigation is needed to resolve this issue.
There are several possible solutions to the three problems mentioned above. Genes are exchanged between plants via pollen. Two ways to ensure that non-target species will not receive introduced genes from GM plants are to create GM plants that are male sterile (do not produce pollen) or to modify the GM plant so that the pollen does not contain the introduced gene. Cross-pollination would not occur, and if harmless insects such as monarch caterpillars were to eat pollen from GM plants, the caterpillars would survive.

Another possible solution is to create buffer zones around fields of GM crops. For example, non-GM corn would be planted to surround a field of B.t. GM corn, and the non-GM corn would not be harvested. Beneficial or harmless insects would have a refuge in the non-GM corn, and insect pests could be allowed to destroy the non-GM corn and would not develop resistance to B.t. pesticides. Gene transfer to weeds and other crops would not occur because the wind-blown pollen would not travel beyond the buffer zone. Estimates of the necessary width of buffer zones range from 6 meters to 30 meters or more. This planting method may not be feasible if too much acreage is required for the buffer zones.

Human health risks
Allergenicity Many children in the US and Europe have developed life-threatening allergies to peanuts and other foods. There is a possibility that introducing a gene into a plant may create a new allergen or cause an allergic reaction in susceptible individuals. A proposal to incorporate a gene from Brazil nuts into soybeans was abandoned because of the fear of causing unexpected allergic reactions. Extensive testing of GM foods may be required to avoid the possibility of harm to consumers with food allergies. Labeling of GM foods and food products will acquire new importance, which I shall discuss later.

Unknown effects on human health There is a growing concern that introducing foreign genes into food plants may have an unexpected and negative impact on human health. A recent article published in Lancet examined the effects of GM potatoes on the digestive tract in rats. This study claimed that there were appreciable differences in the intestines of rats fed GM potatoes and rats fed unmodified potatoes. Yet critics say that this paper, like the monarch butterfly data, is flawed and does not hold up to scientific scrutiny. Moreover, the gene introduced into the potatoes was a snowdrop flower lectin, a substance known to be toxic to mammals. The scientists who created this variety of potato chose to use the lectin gene simply to test the methodology, and these potatoes were never intended for human or animal consumption.
On the whole, with the exception of possible allergenicity, scientists believe that GM foods do not present a risk to human health.

Economic concerns
Bringing a GM food to market is a lengthy and costly process, and of course agri-biotech companies wish to ensure a profitable return on their investment. Many new plant genetic engineering technologies and GM plants have been patented, and patent infringement is a big concern of agribusiness. Yet consumer advocates are worried that patenting these new plant varieties will raise the price of seeds so high that small farmers and third world countries will not be able to afford seeds for GM crops, thus widening the gap between the wealthy and the poor. It is hoped that in a humanitarian gesture, more companies and non-profits will follow the lead of the Rockefeller Foundation and offer their products at reduced cost to impoverished nations.

Patent enforcement may also be difficult, as the contention of the farmers that they involuntarily grew Monsanto-engineered strains when their crops were cross-pollinated shows. One way to combat possible patent infringement is to introduce a "suicide gene" into GM plants. These plants would be viable for only one growing season and would produce sterile seeds that do not germinate. Farmers would need to buy a fresh supply of seeds each year. However, this would be financially disastrous for farmers in third world countries who cannot afford to buy seed each year and traditionally set aside a portion of their harvest to plant in the next growing season. In an open letter to the public, Monsanto has pledged to abandon all research using this suicide gene technology.

• Deborah B. Whiteman. (2000). Genetically Modified Foods: Harmful or Helpful? Retrieved on 5th July 2010, from CSA. Website: http://www.csa.com/discoveryguides/gmfood/overview.php

New allergens could be inadvertently created
- known allergens could be transferred from traditional foods into GM foods. For instance, during laboratory testing, a gene from the Brazil nut was introduced into soybeans. It was found that people with allergies to Brazil nuts could also be allergic to soybeans that had been genetically modified in this way and so the project was ceased. No allergic effects have been found with currently approved GM foods.

Antibiotic resistance may develop
- bioengineers sometimes insert a selectable ‘marker’ gene to help them identify whether a new gene has been successfully introduced to the host DNA. One such marker gene is for resistance to particular antibiotics. If genes coded for such resistance enter the food chain and are taken up by human gut microflora, the effectiveness of antibiotics could be reduced and human infectious disease risk increased. Research has shown that the risk is very low; however, there is general agreement that use of these markers should be phased out.

Cross-breeding
- other risks include the potential for cross-breeding between GM crops and surrounding vegetation, including weeds. This could result in weeds that are resistant to herbicides and would thus require a greater use of herbicides, which could lead to soil and water contamination. The environmental safety aspects of GM crops vary considerably according to local conditions.

Herbicide tolerant (HR) crops
- the introduction of the glyphosate resistant soybean in 1996 was the start of crops that gave farmers an opportunity to reduce the cost of their herbicide use. However, the increasing acreage of HR crops (such as soybean and canola) has resulted in an increase in the types of weeds that are now glyphosate resistant (GR). These GR weeds may have a major environmental influence on crop production in years to come.

Pesticide resistant insects
- the genetic modification of some crops to permanently produce the natural biopesticide Bacillus thuringiensis (Bt) toxin could encourage the evolution of Bt-resistant insects, rendering the spray ineffective. Wherever pesticides are used, insect resistance can occur and good agricultural practice includes strategies to minimise this.

Biodiversity
- growing GM crops on a large scale may also have implications for biodiversity, the balance of wildlife and the environment. This is why environmental agencies closely monitor their use. Since bees are used to pollinate crops, there is also some suggestion that GM crops may affect organic farming.

Cross-contamination
- plants bioengineered to produce pharmaceuticals (such as medicines) may contaminate food crops. Provisions have been introduced in the USA requiring substantial buffer zones, use of separate equipment and a rule that land used for such crops lie fallow for the next year.

Pesticide use
- the use of pesticide resistant (Bt) crops would suggest a reduction in the application of pesticides; however, recent surveys in the USA suggest that Bt-corn that targets corn borer has not lowered pesticide use, since most pesticides are directed against other corn pests.

Health effects
- minimal research has been conducted into the potential acute or chronic health risks of using GM foods and of their performance in relation to a range of health effects. Research also needs to involve independent (not company-based) assessment of the long-term effects of GM crops in the field and on human health.

Social and ethical concerns
Concerns about the social and ethical issues surrounding genetic modification include:

• The possible monopolisation of the world food market by large multinational companies that control the distribution of GM seeds.
• Using genes from animals in plant foods may pose ethical, philosophical or religious problems. For example, eating traces of genetic material from pork could be a problem for certain religious or cultural groups.
• Animal welfare could be adversely affected. For example, cows given more potent GM growth hormones could suffer from health problems related to growth or metabolism.
• New GM organisms could be patented so that 'life' itself could become commercial property through patenting.

Regulation of GM foods
Current food regulations in Australia state that a GM food will only be approved for sale if it is safe and is as nutritious as its conventional counterparts. Food regulatory authorities require that GM foods receive individual pre-market safety assessments prior to use in foods for human consumption. The principle of ‘substantial equivalence’ is also used. This means that an existing food is compared with its genetically modified counterpart to find any differences between the existing food and the new product. The assessment investigates:

• Nutritional content
• Toxicity (using similar methods to those used for conventional foods)
• Tendency to provoke any allergic reaction
• Stability of the inserted gene
• Whether there is any nutritional deficit or change in the GM food
• Any other unintended effects of the gene insertion.
  
• Better Health Channel. (2010, February). Genetically Modified Foods. Retrieved from
  http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Genetically_modified_foods
  
  

The world population has topped 6 billion people and is predicted to double in the next 50 years. Ensuring an adequate food supply for this booming population is going to be a major challenge in the years to come. GM foods promise to meet this need in a number of ways:- Pest resistance Crop losses from insect pests can be staggering, resulting in devastating financial loss for farmers and starvation in developing countries. Farmers typically use many tons of chemical pesticides annually. Consumers do not wish to eat food that has been treated with pesticides because of potential health hazards, and run-off of agricultural wastes from excessive use of pesticides and fertilizers can poison the water supply and cause harm to the environment. Growing GM foods such as B.t. corn can help eliminate the application of chemical pesticides and reduce the cost of bringing a crop to market.

- Herbicide tolerance For some crops, it is not cost-effective to remove weeds by physical means such as tilling, so farmers will often spray large quantities of different herbicides (weed-killer) to destroy weeds, a time-consuming and expensive process, that requires care so that the herbicide doesn't harm the crop plant or the environment. Crop plants genetically-engineered to be resistant to one very powerful herbicide could help prevent environmental damage by reducing the amount of herbicides needed. For example, Monsanto has created a strain of soybeans genetically modified to be not affected by their herbicide product Roundup ®. A farmer grows these soybeans which then only require one application of weed-killer instead of multiple applications, reducing production cost and limiting the dangers of agricultural waste run-off.

- Disease resistance There are many viruses, fungi and bacteria that cause plant diseases. Plant biologists are working to create plants with genetically-engineered resistance to these diseases.

- Cold tolerance Unexpected frost can destroy sensitive seedlings. An antifreeze gene from cold water fish has been introduced into plants such as tobacco and potato. With this antifreeze gene, these plants are able to tolerate cold temperatures that normally would kill unmodified seedlings. (Note: I have not been able to find any journal articles or patents that involve fish antifreeze proteins in strawberries, although I have seen such reports in newspapers. I can only conclude that nothing on this application has yet been published or patented.)

- Drought tolerance/salinity tolerance As the world population grows and more land is utilized for housing instead of food production, farmers will need to grow crops in locations previously unsuited for plant cultivation. Creating plants that can withstand long periods of drought or high salt content in soil and groundwater will help people to grow crops in formerly inhospitable places.

- Nutrition Malnutrition is common in third world countries where impoverished peoples rely on a single crop such as rice for the main staple of their diet. However, rice does not contain adequate amounts of all necessary nutrients to prevent malnutrition. If rice could be genetically engineered to contain additional vitamins and minerals, nutrient deficiencies could be alleviated. For example, blindness due to vitamin A deficiency is a common problem in third world countries. Researchers at the Swiss Federal Institute of Technology Institute for Plant Sciences have created a strain of "golden" rice containing an unusually high content of beta-carotene (vitamin A). Since this rice was funded by the Rockefeller Foundation, a non-profit organization, the Institute hopes to offer the golden rice seed free to any third world country that requests it. Plans were underway to develop a golden rice that also has increased iron content. However, the grant that funded the creation of these two rice strains was not renewed, perhaps because of the vigorous anti-GM food protesting in Europe, and so this nutritionally-enhanced rice may not come to market at all.

- Pharmaceuticals Medicines and vaccines often are costly to produce and sometimes require special storage conditions not readily available in third world countries. Researchers are working to develop edible vaccines in tomatoes and potatoes. These vaccines will be much easier to ship, store and administer than traditional injectable vaccines.

- Phytoremediation Not all GM plants are grown as crops. Soil and groundwater pollution continues to be a problem in all parts of the world. Plants such as poplar trees have been genetically engineered to clean up heavy metal pollution from contaminated soil.

• Deborah B. Whiteman. (2000). Genetically Modified Foods: Harmful or Helpful? Retrieved on 6th July 2010, from ProQuest. Website: http://www.csa.com/discoveryguides/gmfood/overview.php

• Food & Environment Hygiene Department. (2010). International Development in Labeling of GM Food. Retrieved on 6th July 2010, from FEHD. Website: http://www.fehd.gov.hk/english/safefood/gmf/gen_info4.html

- Labeling of GM food is not for safety reasons, but to let the consumers to aware about their choices.
- Labeling of GM foods in Singapore is aligned with international trends and practices.
- Compulsory labelling of GM food is not practiced internationally, by making it mandatory, it could cause reduce in supply and rise in food costs.

- AVA and GMAC monitor international developments closely to ensure labelling requirements are up to date.
- Singapore is working closely with the Codex Committee on Food Labelling to come up with acceptable guidelines on labelling of GM food.
- GMAC also assures consumers that food available in Singapore, including GM food, is safe for consumption.
- Current food regulations do not require GM food to be specially labelled.
- However, it has to meet existing food labelling requirements (ingredient listing and information) to assist in tracing and recall.

• Goh, S.Y. (2008). All food here, including GM food, safe to eat: AVA. Retrieved on 11th June 2010, from AVA. Website: http://www.gmac.gov.sg/News/2008/2008_03_25.html

GM food is considered to be safe for consumption internationally after many reviews done by various international scientific organizations for many years. All GM food must pass rigorous risk assessments to ensure it is safe for human consumption before it can be sold in the international market. GM food is governed by guidelines at both international and country levels. The international guidelines for assessing the safety of food derived from GM organisms are issued by the Codex Alimentarius Commission, which is the international reference body for food standards.

In Singapore, the Genetic Modification Advisory Committee (GMAC) sets guidelines for the import, dispensation and use of GM products. GMAC was established in 1999 to oversee and advise on research and development, production, use, handling and release of GM organisms in Singapore. The Agri-Food & Veterinary Authority (AVA) in Singapore also follows the guidelines of both Codex and GMAC for assess and approval of GM foods for consumption in Singapore.

• Goh, S.Y. (2008). All food here, including GM food, safe to eat: AVA. Retrieved on 11th June 2010, from AVA. Website: http://www.gmac.gov.sg/News/2008/2008_03_25.html

• Arpad Pusztai. (2001). Genetically Modified Foods: Are They a Risk to Human/Animal Health?. Retrieved on 1st June 2010, from American Institute of Biological Sciences. Website: http://www.actionbioscience.org/biotech/pusztai.html


• Whitman, D.B. (2000). Genetically Modified Foods: Harmful or Helpful? CSA Discovery Guides Retrieved on 4th July, from CSA. Website: http://www.csa.com/discoveryguides/gmfood/overview.php


• Genetic Modification Advisory Committee, Singapore. (2007) Genetic Modified Organisms. Retrieved on 2nd July 2010, from GMAC. Website: http://www.gmac.gov.sg/Index_FAQs_Genetically_Modified_Organisms.html


• Union of Concerned Scientist. (2010) Genetic Engineering Techniques. Retrived on 18 June 2010, from UCSUSA. Website: http://www.ucsusa.org/food_and_agriculture/science_and_impacts/science/genetic-engineering-techniques.html


• Human Genome Project Information. (2008) Genetic Modified Foods and organisms. Retrieved on 2nd July 2010, from ORNL. Website: http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml


• Union of Concerned Scientist. (n.d.) Genetic Engineering Techniques. Retrieved on 18th June 2010, website: http://croptechnology.unl.edu/download.cgi


• Brandner, D. L. (2002). PCR-Based Detection of Genetically Modified Foods. Retrieved on 4th July, from http://ucbiotech.org/resources/manuals/GMO_detection.pdf