Sunday, July 22, 2007

How are GMOs developed?

GMO stands for Genetically Modified Organism

The steps involved in developing genetically modified organism are shown below:

  1. Identify a particlar characteristic from any organism (e.g. a plant, animal or microorganism) and work out which gene or genes in the organism are responsible for producing that characterisitc. E.g. the desired characterisitc and the gene that produces this characteristics has been identified in a microorganism (a bacterium). This is the gene of interest.
  2. Use the techiniques of moleculare biology to isolate and copy the required gene. If the gene of interest was found in a bacterium it will have an 'on switch' (and other switches) that function only in bacterial cells. For a gene to function in a different type of cell (for example, in a plant cell), the bacterial switches need to be removed and different switches added to the gene to allow it to function in a plant cell. These switches in all plant cells or in spcific plant tissues (e.g. in root tissue only), so that the new trait will only be switched on in the roots.
  3. When developing a GMO, add appropriate gene switches to the gene of interest, to allow it to function in the cells of the recipient organism.
  4. The gene of interst, together with its gene switches, is inserted into the cells of the host organism, again using molecular biology techniques. Cell with the new gene inserted into their genome are referd to as 'transformed' cells. They contain all the usual genes of the recipient organism as well as the new gene or genes with which they have been transformed.
  5. Grow transformed cells into whole plants in the laboratory; this is done using selective nutrient-rich media. The plants are examined to ensure that they have the desired physical characteristic conferred by the new gene.
  6. Genetically modified plants are bred with conventional plants of the same variety to roduce seed for further tesing and possibly for further commercial use. The entire process from the initial gene selection to commercial producion can take up to 10 years or more.

Basis for approval of GM foods

Basis for approval of GM foods (The safety assessment process)

FSANZ prepares a detailed report on the safety assessment of each new GM food, covering all the points outlined below. Ingeneral, a GM food is considered safe for human consumption if FSANZ is satisfied of the following:

All new genetic material has been examined in detail.
  • Where did the new genetic material come from, what is its function, how was it put into the GM food and how is it arranged within the genetic material of the plant or animal?

The new genetic material stays the same and is passed on in a predictable way from generation to generation.

  • Is the new genetic material stably intergrated within the DNA of the GM organism?
  • Is the novel trait expressed consistently over a number of generation?

All new proteins have been examined in detail.

  • Where and when re the new proteins found in the plant or animal?
  • Do they have the expected size, structure and biological activity?

The new proteins are unlikely to be toxic or allergenic.

  • Do the new proteins come from living organisms that contain no major toxins or allergens ?
  • Are the new proteins dissimilar to known toxins and allergens?
  • Do the new proteins lack other physical and biochemical characteristics typical of toxins and allergens?

The new proteins do not cause any detectable toxicity in animal studies.

  • When the purified new proteins are given in large doses to rats or mice, are there any adverse effects?

The potential transfer of new genetic material to bacterial cells in the human digestive tract will not have a significant impact on human health.

  • Are antbiotic resistance genes present? Is the corresponding anitbiotic used in human or veterinary medicine?
  • What would be the health impact if the new genes were to be transferred to bacteria in the human gut?

The composition of the food, including naturally occuring toxins, allergens and antinutrients, is not significant altered compared to the non GM food.

  • Is the composition of the food (for example, the proteins, fat, fibre, carbohydrate, amino acids, vitamins, minerals, moisture content, and other biologically acitve molecules) substainlly different from that of the conventional food?
  • If so, does the difference found in the GM food affect the safety of the food, and will it make the food less nutritious or healthy?

Regulation and labelling of GM foods

According to Australia New Zealand Food Standards Code
  • Prohibits the use of additives, processing aids and nutritive substances in food unless there is a specific permission for these substances following a safety asssessment.
  • Prohibits the use of novel foods, irradiated foods and foods produced using gene technology unless there is a specific permission for these foods following a safety assessment.
  • Specifies maximum limits for contaminants and natural toxicants in food
  • Establishes microbiological and processing requirements for food
  • Specifies the composition and labelling requirements for many commodities.

According to Standard 1.5.2-Food Produced Using Gene Technology, of the Australia New Zealand Food Standards Code regulates food derived from GM plants, animals or microorganisms. - It does not apply to GM food additives or processing aids, which already overed by other food standards.

Any GM foods (or ingredients derived from them) that are listed in Standard 1.5.2 have passed the safety assessment and approval process, and can therefore be sold in Australia and New Zealand, and used to make other foods.

Safety assessments of GM foods

Under Standard 1.5.2, GM foods must be assessed for safety, and only those found to be safe are approved for sale. FSANZ is responsible for carrying our safety assessments of GM foods on behalf of the Australian Government, the state and territory governments of Australia, and the Government of New Zealand. In doing so, FSANZ takes a cautious approach because, even though most GM foods are derived from foods with a long-established history of safe human consumption (such as corn and soybean), the GM versions are new to the diet.

Labelling of GM foods

Standard 1.5.2 also contains provisions for the labelling of GM foods-these provisions have been in effect since December 2001. The safety of a GM food is assessed before it can be sold as food: therefore, the purpose of labelling is simply to provide information to consumers, allowing them to purchase or avoid GM foods depending on their own views and beliefs. The GM food labelling regulations, which are among the most stringent in the world, represent a balance between the needs of consumers and what governments can realistically enforce.

Under Standard 1.5.2, if a food, food ingredient, additive or processing aid contains novel DNA or protein that has come from an approved GM food, it must be labelled with the words 'genetically modified'. Labelling regulation also cover GM foods that differ in composition to the conventional counterpart; in this case, he labelling must make claer to consmers the altered characteristics of the food.

There are some exemptions to the labelling requirements for GM foods. Foods that do not need to be labelled as 'genetically modified' include highly refined foods that contain no DNA or protein (for example, oil made from GM soy beans), and foods in which GM ingredients are present accidentally and make up lessthan 1% of the final food.

Role of other agencies

In Australia and New Zealand, FSANZ is not the only government agency involved with the regulation of GM microorganisms, plants, and animals and their products. As shown in Table 2.1, the responsibilities of other agencies cover broader issue than food safety, such as the environment, quarantine and the registraion of agricultural chemicals. Where products require the approval of several agencies, the agencies coordinate with one another.

Concerns of GM foods

Concerns of people with regards to GM foods

Other frequently asked questions would be ‘what if I eat DNA in GM food?’, ‘How about allergens and toxins in GM foods?’, ‘Concerns of antibiotic resistance genes in GM foods’ and ‘What about herbicides and pesticides residues in GM foods?’. Firstly, we eat DNA from our everyday food which will be broken down in the digestive system into building blocks and can be metabolized by body cells. Eating DNA from GM or conventional foods will not change our own DNA or that of our children. Secondly, certain proteins in food can cause unusual immune reaction are known as allergens. If conventional foods contain allergens, GM foods similarly contain the same allergens. But food monitoring bodies will check to ensure the level of these naturally occurring allergens in GM foods does not increased significantly and new proteins found in GM foods are not allergenic. Same for toxin, toxic substances that are naturally present in many conventional foods can also is found in GM foods. Thus, government bodies would compare the usual amount of these naturally-occurring toxins that are found in the conventional with the GM foods to ensure that the toxins level consumed are not harmful to health. New protein in GM food is also check if it is toxic, if it is toxic and may cause adverse health effects at levels of expected dietary intake, it would not be approved for sale. Thirdly, the worries of people about consuming antibiotic resistance genes in GM foods is it could transfer to disease-causing bacteria in human digestive tract and could results in infections that are resistant to treatment with antibiotics. But antibiotic resistance genes that are currently present in GM foods are not widely used in human medicine because resistance to them is already widespread. Lastly, all foods sold must comply with relevant maximum residue limits, whether the foods have been genetically modified or not. Thus, even if herbicide or pesticide used changes because crops have been modified to tolerate these chemicals, they will not contain unsafe levels of residues. In some cases, level of these chemicals used on GM crops might be reduced.

Tuesday, July 17, 2007

Controversial issues about GM foods (part 2)

Support of Genetic Engineering

1. Ethical and moral isues:
Scientists throughout history have been persecuted and even put to death by fearful people who accuse them of playing God. Yet, today many of the world's citizens enjoy a long and healthy life of comfort and convenience due to once0feared scientific advances put to practical use.

2. Advanced technology:
Recombinant DNA technology is precise and reliable. Many of the most exciting recent advances in medicine, agriculture, and technology were made possible by the application of this technology.

3. Environmental protection:
Genetic engineering may be the only hope of saving rain forest and other habitats from destruction. Through genetic engineering, farmers can make use of previously unproductive lands such as salt-rich soils and arid areas.

4. Genetic improvements:
Genetic side effects are more likely to benefit the environment than to harm it.

5. Improved crop resistance:
Pests and diseases can be specifically fought on a case-by-case basis. Biotechnology is the key to defense.

6. Gene pool reserved:
Thanks to advances in genetics, laboratories around the world are able to stockpile the genetic material of millions of species that, without such advances, would have been lost forever.

7. Everyone profits:
Industries benefit from genetic engineering, and a thiving food industry benefits the nation and it people, as witnessed by countries lacking such industries. Genetic engineering promises to provide adequate nutritious food for millions who lack such food today. Developed nations gain cheaper, more attractive, more delicious fods with greater variety and availability year round.

8. Safe for people:
Human safety testing of genetically altered foodstuff are known, and foods likely to contain them are clearly labeled to warn consumers.

9. Control of allergens:
A few allergens can be transferred into foods, but these are known, and foods likely to contain them are clearly labeled to warn consumers.

10. Increased nutrients:
Genetic modifications can easily enhance the nutrients in foods.

11. Excellent product tracking:
The identity and location of genetically altered fodstuffs are known, and they can be tracked should problems arise.

12. Conservative use of herbicides:
Farmers will not waste expensive berbicides in second or third applications when the precribled amount gets the job done the first time.

13. Reduced pesicides on foods:
Pesticides produced by produce in tiny amounts known to be safe for consumption are more predictable than applications by agricultural workers who make mistakes. Becasue other genetic manipulations will eliminate the need for postharvest spraying, fewer pesticides will reach the dinner table.

14. Sufficient regulation and rapid response:
Government agencies are efficient in identifying and correcting problems as they occur in the industry.

Controversial issues of GM Foods (part 1)

Opposition to Genetic Engineering

1. Ethical and moral issues:
It is immoral to 'play God' by mixing genes from organisms unable to do so naturally. Religious and vegetarian groups object to genes from prohibited species occurring in their allowable foods.

2. Imperfect Technology:
The technlogy is young and imperfect- genes rarely function in just one way, their placement is imprecise ('shotgun'), and all of their potential effects are impossible to predict. Toxins are likely to be produced as the desired triat. Over 95% of DNA is called "junk"because scientists have not yet determined its function.

3. Evironmental concerns:
Environmental side effects are unknown. The power of a genetically modified organism to change the world's environments is unknown until such changes actually occur - then the 'genie is out of the bottle'. Once out, the genie cannot be put back in the bottle becasue insects, birds, and the wind distribute genetically altered seed and pollen to points unknown.

4. Genetic pollution:
Other kinds of pollution can often be cleaned up with money time, and effort. Once genes are spliced into living things, those genes forever bear the imprint of human tampering.

5. Crop Vulnerability:
Pests and disease can quickly adapt to overtake genetically idntical plants or animalsaround the world. Diversity is key to defense.

6. Loss of gene pool:
Loss of geneticdiversity threatens to deplete valuable gene banks from which scientists can develop new agricultural crops.

7. Profit motive:
Genetic engineering will profit industry more than the world's poor and hungry.

8. Unproven safety for people:
Human safety testing of genetically altered products is generally lacking. The pollulation is an unwitting experimental group in a nationwide laboratory study for the benefit of industry.

9. Increased allergens:
Allergens can unwittly be transfered into foods.

10. Decreased nutrients:
A fresh-loking tomato or other produce held for several weeks may have lost substanial nutrients.

11. No product tracking:
Without labelling, the food industry cannot track problems to the source.

12. Overuse of herbicides:
Farmers, knowing that their crops resists herbicide effects, will use them liberally.

13. Increased consumption of pesticides:
When a pesticide is produced by the flesh of produce, consumers cannot wash it off the skin of the produce with running water as they can with ordinary sprays.

14. Lack of oversight:
Government oversight is run by industry people for the benefit of industry- no one is watching out for the consumer.

Sunday, May 27, 2007

Info on some common bacteria

Campylobacter jejuni
Incubation period: 2-5 days
Signs and Symptoms: Diarrhea, cramps, fever, muscle pain, nausea and vomiting
Associated Foods: Undercooked or raw poultry and beef, unpasteurized milk and dairy products, and contminated water.
Duration of Illness: 2-10 days

Clostridium botlinum (toxin-producing)
Incubation period: 3-30 days
Signs and Symptoms: Lethargy, weakness, poor feeding, constipation, poor head control, poor gag and suck, poor muscle tone
Associated Foods: Honey, home-canned fruits and vegetables.
Duration of Illness: Variable

Clostridinum perferingens
Incubation period: 8-16 hours
Signs and Symptoms: Watery diarrhea, nausea, abdominal cramps
Associated Foods: Meats, poultry, gravy, dried or precooked foods and beans.
Duration of Illness: 1-2 days

E.coli (toxin-producing)
Incubation period: 1-8 days
Signs and Symptoms: Severe diarrhea(often bloody), abdominal pain and vomiting
Associated Foods:Undercooked beef, unpasteurized milk and juice, raw fruits and vegetables, salami, salad dresing, imported cheese, and conaminated water.
Duration of Illness: 5-10 days

Listeria monocytogenes
Incubation period: 9-48 hours for gastrointestinal symptoms
Signs and Symptoms: Fever, muscle aches, and nausea or diarrhea
Associated Foods: Fresh soft cheeses, unpasteurized milk and cheese, ice cream, raw vegetables, raw and cooked poultry, raw meat and fish, ready-to-eat deli meat and hotdogs.
Duration of Illness: Variable

Salmonella
Incubation period: 1-3 days
Signs and Symptoms: Diarrhea, fever, abdominal, cramps, vomiting, headache, constipation, chills and muscle pain
Associated Foods: Contaminated eggs, poultry, unpasteurized milk and juice, cheese, raw meat and fish, and shrimp, yeast, coconut, salad dressing, cake mixes, cream-filled desserts, peanuts butter, cocoa, chocolate, and raw fruits and vegetables.
Duration of Illness: 4-7 days

Shigella
Incubation period: 1-2 days
Signs and Symptoms: Abdominal cramps, fever, nausea, vomiting,chills, fatigue, and diarrhea
Associated Foods: Food or water contaminated with fecal material, raw vegetables, egg salad
Duration of Illness: 4-7 days

Staphylococcus aureus (toxin-producing)
Incubation period:
Signs and Symptoms: Sudden onset od severe nausea and vomiting, exhaustion, and abdominal cramps. Diarrhea and fever may be present.
Associated Foods: Improperly refrigerated meats, poultry, eggs, potato salad, egg salad and cream pastries
Duration of Illness: 1-2 days