Genetic Modification

Source obtained from: http://www.gurupedia.com/g/gm/gmo.htm#Genetic_modification_of_bacteria

Genetic Modification of Bacteria

Three processes are known by which the genetic composition of bacteria can be altered: transformation, conjugation and transduction.

• Transformation is a process by which some bacteria are naturally capable of taking up DNA to acquire new genetic traits. This phenomenon was discovered by Fred Griffith in 1928, although the fact that it was specifically DNA molecules that carried the genetic information was not proven until 1944. Bacteria that are competent to undergo transformation are frequently used in molecular biology.
• In conjugation, DNA is transferred from one bacteria to another via a temporary connecting strand of DNA called a pilus (a process analogous to but biologically distinct from mating). Conjugation is not widely used for the artificial genetic modification of bacteria.
• Transduction refers to the introduction of new DNA into a bacterial cell by a bacteriophage (a virus that infects bacteria).

Genetic Modification of plants

The principle technique for the genetic modification of plants is based on a natural ability of the bacteria Agrobacterium tumefaciens. This bacteria infects plants and causes a tumor-like growth termed a crown gall. Agrobacterium causing crown galls contains a plasmid (a circular piece of DNA) that transfers from the bacteria into the infected plant and integrates into the plant's genome. The transferred genes cause the plant to form the gall, which houses the bacteria and produces nutrients that support the bacteria's growth. A number of scientists contributed to this discovery throughout the late 1960s and the 1970s, with key discoveries by Jeff Schell, Marc Van Montagu, Georges Morel and Jacques Tempé. By 1983 biotechnology had reached the point where it was possible to insert additional genes of interest into Agrobacterium and thus transfer those genes into plants.

Genetic Modification of animals

Like bacteria and plants, animals can be genetically modified by viral infection. However, the genetic modification occurs only in those cells that become infected, and in most cases these cells are eventually eliminated by the immune system. In some cases it is possible to use the gene-transferring ability of viruses for gene therapy, i.e. to correct diseases caused by defective genes by supplying a normal copy of the genes. Permanent genetic modification of whole animals can be accomplished in mice. The process begins by first genetically modifiying a mouse embryonic stem cell. This is normally done by physically introducing into the cell a plasmid that can integrate into the genome by homologous recombination. This altered cell is implanted into a blastocyst (an early embryo), which is then implanted into the uterus of a female mouse. A pup born from this blastocyst will be a chimera containing some cells derived from the unmodified cells of the blastocyst and some derived from the modified stem cell. By selecting mice whose germ cells (sperm or egg producing cells) developed from the modified cell and interbreeding them, pups that contain the genetic modification in all of their cells will be born.

Continuation on set-backs of producing GM Foods

Source obtained from: http://www.idebate.org/event_documents/3c959b698e.doc

• Immune resistance – the more organic materials' genetic makeup are tampered with, the more likely human immunity is weakened
• Intrusion into the delicate balance of ecosystems – which may threaten biodiversity
• Toxin transfer – genetically modified organisms (GMOs) lower immune resistance in animals which may transmit toxins into groundwater that, in turn, passes disease onto humans
• Trade disputes – companies and/or countries who dominate the technology of GM foods risk conflicts and trade wars between nations
• Dependency – GM foods risk the dependence of developing nations on industrialized nations, via the companies from industrialized countries

Genetically Modification of Foods

What is genetic modification of foods

• Plants

Source obtained from: http://carroll1.cc.edu/~fys/ppp/pros.htm

Pesticides and Insecticides Reduction
The use of genetically altered crops can help reduce the pollution due to the use of harmful pesticides and insecticides. Certain crops can be genetically altered so that they have an insecticide or pesticide already built into them. These plants will deter insects and resist fungus with the minimum use of chemicals. This in turn means that less of these chemicals will make it into our drinking water, lakes, rivers and streams. By using these plants we will also lessen the chance of other animals being harmed. The insecticides and pesticides that are used can affect many populations of animals. It can sometimes act as a poison for many birds and small animals. The chemicals also can harm the fish in the surrounding rivers and lakes. The genetically altered plants allow us to use less chemicals and prevent hurting many animals.
Crops can also be genetically altered for herbicide resistance. This allows farmers to use less hazardous and more short-term herbicides. It also reduces the need for tilling the soil. This in turn reduces soil erosion.

Benefits of Genetically Modifying Plants

• Pesticide/Insecticide Reduction
• Medical Applications
• GM Plants will be Tastier and Healthier
• Disease Resistant Plants
• Help World Hunger
• Nutritional Value

Benefits and the set-backs of Producing GM foods

Benefits in GM Foods
Source pbtained from:http://www.foothilltech.org/9th-grade-action-based-project/health-care/genetically_modified_foods-1984.htm

The first and foremost issue is, what are the benefits of the use of genetically modified organisms (GMO) in food products. Humans are not the only beneficiaries of GM foods; there are benefits for crops, animals and society as a whole. Genetic engineering may enhance the taste and quality of food products. It reduces that maturation time and increases nutrients found in the food. Genetic engineering improves resistance to disease, pests and herbicides and increases yields and stress tolerance. Biotechnology companies have rushed to produce characteristics such as resistance to drought, disease and insects in food crops that previously did not have them. Many new crops require less processing in the factories and fewer additives. Because they have genes that make them last longer, there is less wastage. Another possible benefit is the reduced use of pesticides, fertilizers and energy compared to conventional farming methods. Farmers do not need to till the soil, lessening soil erosion and reducing labor and machinery. Animals reap the benefits of GM foods – they have an increased resistance, productivity, and hardiness. They give better yields of meat, eggs and milk. Their health is also improved through the consumption of this food. Moreover, genetic engineering not only produces advanced crop products, it benefits the environment as a whole. Genetic engineering produces friendly bioherbicides and bioinsecticides. It provides for better natural waste management and helps conserve soil, water and energy. Additionally, one of the most important benefits of GM foods is the increased food security for growing populations. Gm foods offer greater yields and more resistance to pests and viruses which in turn assure the growing population that there will be enough food to eat.

Set-backs of producing GM foods
Consumers are often not aware that they are consuming GMOs, as the Federal Drug Administration (FDA) has not yet made labeling of GMOs in food a requirement. There is continued research and more products are found to contain GMOs. GM foods are unlabelled and are everywhere. The possibilities of human allergies to these organisms or chemicals is a risk that some members of society do not wish to take yet they have no choice as they are not aware which foods contain the GMO. GM food could be a serious risk to human health. Proteins made from the foreign genes might be directly toxic to humans. The genes could alter the functioning of a plant in ways that make its food component less nutritious or more prone to carrying elevated levels of the natural poisons that many plants contain in small amounts that could be toxic to humans.

The following is another of my research for the benefits and the set-backs of producing GM Foods in point form.

Source obtained from: http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml

Benefits

Crops

• Enhanced taste and quality
• Reduced maturation time
• Increased nutrients, yields, and stress tolerance
• Improved resistance to disease, pests, and herbicides
• New products and growing techniques

Animals

• Increased resistance, productivity, hardiness, and feed efficiency
• Better yields of meat, eggs, and milk
• Improved animal health and diagnostic methods
  

Environment

• "Friendly" bioherbicides and bioinsecticides
• Conservation of soil, water, and energy
• Bioprocessing for forestry products
• Better natural waste management
• More efficient processing
  

Society

• Increased food security for growing populations

Controversies

Safety

• Potential human health impact: allergens, transfer of antibiotic resistance markers, unknown effects Potential environmental impact: unintended transfer of transgenes through cross-pollination, unknown effects on other organisms (e.g., soil microbes), and loss of flora and fauna biodiversity

Access and Intellectual Property

• Domination of world food production by a few companies
• Increasing dependence on Industralized nations by developing countries
• Biopiracy—foreign exploitation of natural resources

Ethics

• Violation of natural organisms' intrinsic values
• Tampering with nature by mixing genes among species
• Objections to consuming animal genes in plants and vice versa
• Stress for animal

Labeling

• Not mandatory in some countries (e.g., United States)
• Mixing GM crops with non-GM confounds labeling attempts

Society

• New advances may be skewed to interests of rich countries

Genetically Modified Foods

What is Genetically Modified Foods (GM Foods)?
Source Obtained from: http://www.gm.org/
A genetically modified food is a food product derived in whole or part from a genetically modified organism (GMO) such as a crop plant, animal or microbe such as yeast.

Source Obtained from:http://en.wikipedia.org/wiki/GM_food
Genetically Modified (GM) foods are produced from genetically modified organisms (GMO) which have had their genome altered through genetic engineering techniques. The general principle of producing a GMO is to insert DNA that has been taken from another organism and modified in the laboratory into an organism's genome to produce both new and useful traits or phenotypes. Typically this is done using DNA from certain types of bacteria. GM Foods have been available since the 1990s, with the principal ones being derived from plants; soybean, corn, canola and cotton seed oil.

Modified Atmosphere Packaging

Source obtained from:

http://en.wikipedia.org/wiki/Modified_atmosphere

Modified atmosphere is a common technical definition that describes the practice of modifying the composition of the internal atmosphere of a package (commonly food packages, but this technique is also used for drugs) in order to improve the shelf life.
The modification process often tries to lower the amount of oxygen (O2), moving it from 20% to 0%, in order to slow down the growth of aerobic lifeforms and the speed of oxidation reactions. The removed oxygen can be replaced with nitrogen (N2), commonly acknowledged as an inert gas, or carbon dioxide (CO2), which can lower the pH or inhibit the growth of bacteria.

Gases used in MAP
•CO2 – bacteriostatic and fungistatic properties; inhibits growth of spoilage bacteria
•O2 – normally excluded or set at low concentration because it promotes for eg, fat oxidation
•N2 – counteract package collapse caused by CO2 dissolving in food
- retards growth of aerobic spoilage by microbes
MAP is associated with chilled temperature. Eg, mooncake pastry is chilled to
prevent water loss
• MAP maintains high relative humidity and reduction in water loss

Foodborne Illnesses

What are foodborne illnesses?

Foodborne illnesses are caused by the consumption of contaminated foods or beverages. Such contamination usually arises from improper handling, preparation, or food storage. Therefore, good hygiene practices should be practiced before, during, and after food preparation can reduce the chances of contracting an illness.
There are many kinds of foodborne illnesses which are usually caused by different bacteria or other pathogens on food. They can affect a person by displaying many flu-like symptoms such as nausea, vomiting, diarrhoea or fever. Pathogens refers to bacteria that cause disease or an illness. When certain pathogens enter food, they can cause serious foodborne illnesses, which may be fatal.

What are some common foodborne illnesses found in Meat and Poultry
Source obtained from: http://www.fsis.usda.gov/OA/haccp/higuide.PDF

Campylobacter

Disease and symptoms:

• Causes diarrhea 2-7 days after eating contaminated food
• May cause nerve damage 1-6 weeks after infection.

Source:

• Fecal contamination of raw poultry and meat.

Transmission:

• Cross contamination from raw meat
• Poultry drippings
• Consumption of undercooked food.

Characteristics of Campylobacter:

• Sensitive to heat and drying.
• Grows in reduced oxygen environments.
• Grows at human body temperature.
• Does not grow in acid food.
• Survives but does not grow during refrigeration and freezing.

Clostridium botulinum

Disease and symptoms:

• Blurred or double vision,
• Dry mouth, difficulty swallowing,
• Paralysis of respiratory muscles.
• Vomiting and diarrhea may be present.

Source:

• Soil and the intestinal tract of animals.

Transmission:

• Consumption of toxin that has been formed in food by Clostridium botulinum.

Characteristics of Clostridium botulinum:

• Toxin is destroyed by high heat
• Bacteria can grow in most low-acid foods under low oxygen conditions.
• Bacteria grow best without oxygen.
• High acid (pH 4.6) prevents the occurrence of toxin production.

Clostridium perfringens

Disease and symptoms:

• Diarrhoea 6-24 hours after eating contaminated food.
• Abdominal pain 6-24 hours after eating contaminated food.

Source:

• Intestinal tract of healthy persons and animals.

Transmission:

• Usually exists in inadequately heated or reheated meats.

Characteristics of Clostridium perfringens:

• Has a heat resistant form known as a spore.
• Spores survive normal cooking procedures, including boiling.
• Grows well without oxygen.
• Bacteria grow best at 110-120°F.
• Slow cooling and non-refrigerated storage of cooked meat and poultry permit growth of bacteria to high numbers.

Escherichia coli

Disease and symptoms:

• Causes diarrhoea, which may be bloody
• Occasional fever.
• May result in kidney failure and death, especially in children.

Source:

• Fecal contamination of beef.

Transmission:

• Consumption of raw or undercooked hamburger, contaminated produce, such as sprouts, unpasteurized milk, and juices.

Characteristics:

• Killed by mild heat.
• Grows with or without air. Optimum temperature for growth is human body temperature.
• Grows in moist, low-acid foods.

Salmonella

Disease and symptoms:

• Causes acute diarrhoea
• Vomiting and abdominal pain
• Fever.
• Occasionally, may cause blood stream infections
• Death.

Source:

• Fecal contamination of meat and poultry.

Transmission:

• Primarily from consumption of raw or undercooked eggs, milk, meat and poultry.

Characteristics:

• Killed by mild heat.
• Grows with or without air. Grows best at human body temperature, which is around 37oC.
• Grows very poorly at refrigeration temperatures and does not grow above 130°F.
• Does not grow well or at all in acidic foods.
• Survives well in frozen or dry foods. Bacteria in dry foods are more resistant to heat.

Staphylococcus aureus

Disease and symptoms:

• Vomiting and nausea
• Abdominal cramps
• Diarrhoea

Source:

• May be present on raw meat and poultry but contamination of food is primarily from humans.

Transmission:

• Bacteria multiply in food products to high levels and produce a heat stable toxin.

Characteristics:

• Bacteria killed by mild heat, however
• Toxins are very heat stable, and will withstand thermal processing for prolonged periods.
• Bacteria grow with or without air at body temperatures.
• Toxin not usually produced in acid food.
• Bacteria resistant to high salt (up to 15%).

Listeria monocytogenes

Disease and symptoms:

• Meningitis, which is sudden fever, intense headache, nausea, vomiting and coma).
• Flu-like illness
• Diarrhoea.

Source:

• Post-heat-processing contamination from the plant environment including plant personnel, equipment, floors, walls, drains, condensation from coolers, etc.

Transmission:

• Consumption of contaminated processed ready-to-eat meats.
• Vegetables
• Unpasteurized dairy products.

Characteristics:

• Killed by pasteurization temperatures.
• Grows with or without air (prefers reduced oxygen conditions)
• Able to grow at refrigeration temperatures and high salt concentration.
• Withstands repeated freezing and thawing.
• Survives for prolonged periods in dry conditions.