-Physicochemical Methods
In this method, the mycotoxin is extracted, purified, concentrated and separated via thin-layer chromatography before the mycotoxin in the food sample can be quantified.
-Immuno Assays
Mycotoxins are made to interact with specific antibodies before they are isolated. Radioimmunoassay (RIA) and enzyme-linked immunoabsorbent assay (ELISA) are two techniques of this method.
-Biological Assays
Biological systems such as cell and tissue cultures, animals and microorganisms are used as bioassays to detect and quantify mycotoxins. Furthermore, it can display the physiological and pathological effects of mycotoxins.
Adapted from: Food and Beverage Mycology, 2nd Edition, Larry R. Beuchat, 1987
Monday, July 14, 2008
Mycotoxins
The harmful chemicals produced by fungi in food are referred to as mycotoxins. Mycotoxins do not get eliminated during digestion or even temperature treatments during food processing. These harmful compounds can be carcinogenic, teratogenic, tremorgenic, hemorrhagic and dermatitic. They may also limit growth in affected consumers as protein synthesis is inhibited.
Adapted from: http://en.wikipedia.org/wiki/Mycotoxin and
Food and Beverage Mycology, 2nd Edition, Larry R. Beuchat, 1987
Adapted from: http://en.wikipedia.org/wiki/Mycotoxin and
Food and Beverage Mycology, 2nd Edition, Larry R. Beuchat, 1987
Isolation and Identification of Foodborne Pathogens
Conventionally, the sample food is mixed with a buffer and homogenized before it is placed into a non-selective media for the resuscitation of the microorganisms. Upon revival of the microorganisms, the food sample is incubated in a selective media for selection of specific microorganisms. Then it is placed in a growth media which promotes propagation of the microorganism. The microorganisms go through another selection phase via the use of differential and selective agars. After a specified incubation period, the colonies present on the agar will be isolated. These isolates then undergo biochemical testing for identification and characterization purposes. Cultural methods are labour intensive and time-consuming. Hence, rapid methods have been established to give accurate results, quicker.
Rapid methods include
-Immunological Methods (Antibody-based Assays)
-DNA/RNA Methodology (Nucleic Acid-based Assays)
-Next Generation Technologies
-rTPCR
-Immunosensors/ Biosensors
-DNA Microarrays
Adapted from: Food Microbiology, M.R. Adams & M.O. Moss, 1995
Rapid methods include
-Immunological Methods (Antibody-based Assays)
-DNA/RNA Methodology (Nucleic Acid-based Assays)
-Next Generation Technologies
-rTPCR
-Immunosensors/ Biosensors
-DNA Microarrays
Adapted from: Food Microbiology, M.R. Adams & M.O. Moss, 1995
Wednesday, June 25, 2008
GM food in Singapore
Singapore’s position on GM food is on par with international practice. The Agri-Food & Veterinary Authority (AVA) ensures that GM food are subjected to extensive assessments and approval in other developed countries before they are made available in the Singapore market. Labelling of GM food is also not requirement as making it mandatory will curtail supplies thereby, increasing the prices of food. Nonetheless, the Genetic Modification Advisory Committee (GMAC) and AVA will continue to ensure that labelling requirements in Singapore are in accordance with the latest international developments. Besides, AVA is developing acceptable guidelines on the labelling of GM food with the help of the international Codex Committee on Food Labelling.
Reference:
http://www.ava.gov.sg/NR/rdonlyres/1693236D-7808-4260-BADE-DB7EA7861BEE/20483/STGMFOOD.pdf
Reference:
http://www.ava.gov.sg/NR/rdonlyres/1693236D-7808-4260-BADE-DB7EA7861BEE/20483/STGMFOOD.pdf
Genetic Engineering Technologies (rDNA technology): Microinjection
In this process, DNA is directly injected into cells. Some of these cells will survive and integrate the injected DNA. This method is labour intensive and inefficient compared to other methods.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Genetic Engineering Technologies (rDNA technology): Electroporation
This method is quite similar to somatic hybridization. Instead of fusing two cells together, like in somatic hybridization, this technique fuses the protoplast with the added DNA in the culture medium. An electrical pulse is also used in this method. The transformed cell will then reconstruct its cell wall and grow to a whole, fertile plant. However, the inability for most plant species to regenerate from protoplasts makes this method ineffective.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Genetic Engineering Technologies (rDNA technology): Genetic Engineering Agent (Agrobacterium tumefaciens)
The genetic engineering agent that is responsible for the majority of GM crops is a soil microbe called Agrobacterium tumefaciens. Upon infecting a host cell, this pathogen transfers a segment of its own DNA into the plant cell. The host cell then expresses the transferred genes and the instructions for the production of substances that induce the development of a crown gall (disease) will begin. These substances will then be distributed throughout the plant, causing the food produced by these plant to also contain these substances. By exchanging the crown gall disease-causing DNA with a DNA of interest, new strains of this bacterium can be obtained to introduce new useful genetic material into the host plant. Eventually, the progeny of this whole fertile plant would also contain the same inserted DNA of interest.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Genetic Engineering Technologies (rDNA technology): Microprojectile Bombardment
This is an effective, physical method of DNA delivery in species such as corn, rice and other cereal grains is. In this process, “naked” DNA is adhered to microscopic pellets and shot into plant cells.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Non-genetic Engineering Method: Mutation Breeding
This method involves the exposing of organisms (plants or seeds) to mutagens, be it chemical mutagens or ionizing radiations. These mutagens will induce random changes in the DNA pattern of the organism. The progeny of these mutagenized and matured organisms are then assessed for novel traits. This method produces random effects and is prone to forming mutations that are injurious to human health.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Non-genetic Engineering Method: Somaclonal Variation
When plant cells are grown in vitro (eggs from female ovary are removed and fertilized with male sperm in a laboratory procedure, and then the fertilized egg (embryo) is re-planted in the female), spontaneous mutations will occur, producing progenies with new traits. This method is capable of producing potentially valuable variants in a range of different crops has been largely substituted with more predictable methods.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Non-genetic Engineering Method: Somatic Hybridization
In somatic hybridization, cells are grown in culture mediums where their cell walls are degraded by enzymes such as pectinase, cellulase and hemicellulase, forming protoplasts. These protoplasts are gathered from different sources and fused via electrical shock. This cell fusion technique is easily accomplished but few organisms are capable of growing into a whole, sexually-capable organism.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Non-genetic Engineering Method: Embryo Rescue
At times, human intervention is needed for interspecies gene transfer because the hybrid embryo is unable to mature and sprout. Thus, the hybrid embryo is removed quickly and placed in a tissue-culture where it can reach maturity. This embryo rescue technique allows genes to be transferred from distant, incompatible relatives through intermediate, mildly compatible relatives of both donor and recipient species.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Non-genetic Engineering Method: Interspecies crossing
In interspecies crossing, portions of chromosomes from distant species are recombined via chromosomal translocation. This chromosome engineering referred to as nonrecombinant deoxyribonucleic acid (rDNA) cytogenetic manipulations, is a limiting technique. This is because large portions of chromosomes are transferred in this process including the “bad “genes. Therefore, this method is becoming more competitive with rDNA technology whereby smaller portions of chromosomes, containing the genes of interests, are transferred.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Non-genetic Engineering Method: Simple Selection
Traditionally, “superior” individuals of organisms with the most ideal characteristics are identified and propagated for several years till the population is dominated by the “superior” genotype. This simple selection process can be hastened by the modern marker-assisted selection method, which analyses organisms molecularly to detect individuals with genes that express desired traits. Upon selection and propagation, a “superior” organism is crossed with another “superior” organism to produce a hybrid progeny which displays the combined desired traits of its parents.
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Adapted from: Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
How are foods genetically modified?
Genetic modification includes non-genetic engineering methods and genetic engineering technologies. Both types of methods can be used to alter the genetic makeup of an organism.
However, genetic engineering technologies, which utilizes rDNA technology, is more specific and precise than non-genetic engineering methods. This technology targets an intended change in a gene to cause a specific result.
1. Non-genetic Engineering Methods
- Simple selection
- Interspecies crossing
- Embryo rescue
- Somatic hybridization
- Somaclonal variation
- Mutation breeding
2. Genetic Engineering Technologies (rDNA technology)
- Micro projectile bombardment
- Genetic engineering agent, Agrobacterium tumefaciens
- Electroporation
- Microinjection
Reference
Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
However, genetic engineering technologies, which utilizes rDNA technology, is more specific and precise than non-genetic engineering methods. This technology targets an intended change in a gene to cause a specific result.
1. Non-genetic Engineering Methods
- Simple selection
- Interspecies crossing
- Embryo rescue
- Somatic hybridization
- Somaclonal variation
- Mutation breeding
2. Genetic Engineering Technologies (rDNA technology)
- Micro projectile bombardment
- Genetic engineering agent, Agrobacterium tumefaciens
- Electroporation
- Microinjection
Reference
Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press
Friday, May 16, 2008
Nitrogen and carbon dioxide flushing
Nitrogen flushing in packaged foods improves the shelf life. The presence of nitrogen lowers the amount of oxygen, slowing down the growth of aerobic lifeforms and the speed of oxidation reactions.
Another inert gas that can be used to replace the oxygen is carbon dioxide. This gas can lower the pH or inhibit the growth of bacteria in the food.
Adapted from http://en.wikipedia.org/wiki/Modified_atmosphere
Another inert gas that can be used to replace the oxygen is carbon dioxide. This gas can lower the pH or inhibit the growth of bacteria in the food.
Adapted from http://en.wikipedia.org/wiki/Modified_atmosphere
Wednesday, May 14, 2008
Product Recall
A food recall is the removal of products from sale, distribution and consumption. A recall is a precautionary measure that needs to be implemented when the product poses a possible public health and safety risk to consumers. Products that do not pose a potential risk to public health and safety may also be withdrawn from sale when it has a quality defect or has labelling irregularities.
Types of food recalls
The type of recall depends on the type of product, where it is sold and reason for the recall.
1. Trade Level - involves recovery of the product from distribution centres and wholesalers and may also involve hospitals, restaurants and other major catering establishments, and outlets that sell food manufactured for immediate consumption or food that is prepared on the premises.
2.Consumer Level - involves recovery of the product from all points in the production and distribution networks including any affected product in the possession of consumers.
3.Voluntary Recall - where the manufacturer or importer initiates a food recall
4.Mandatory Recall - where the Director General of NSW Food Authority directs the manufacturer/importer to recall a food product.
Adapted from
http://www.foodauthority.nsw.gov.au/industry/fb-recalls.asp
Types of food recalls
The type of recall depends on the type of product, where it is sold and reason for the recall.
1. Trade Level - involves recovery of the product from distribution centres and wholesalers and may also involve hospitals, restaurants and other major catering establishments, and outlets that sell food manufactured for immediate consumption or food that is prepared on the premises.
2.Consumer Level - involves recovery of the product from all points in the production and distribution networks including any affected product in the possession of consumers.
3.Voluntary Recall - where the manufacturer or importer initiates a food recall
4.Mandatory Recall - where the Director General of NSW Food Authority directs the manufacturer/importer to recall a food product.
Adapted from
http://www.foodauthority.nsw.gov.au/industry/fb-recalls.asp
Friday, April 18, 2008
Consequences of having food poisoning issue
-Monetary compensation for victims (medical and other costs)
-Legal fees
-Higher insurance costs
-Lost market share and profits
-Negative publicity
-Closure of food premises by local authorities
-Incurred costs from internal investigation
-Incurred costs from cleaning, decontamination and replacement of equipment
References:
-http://books.google.com/books?hl=en&lr=&id=kexwWKbS6b4C&oi=fnd&pg=PA121&dq=consequences+of+food+poisoning+on+company&ots=LqpZWpc9pp&sig=4l90c3YJHOHWsknZPcyjpfmFpSA#PPP1,M1
Interdisciplinary Food Safety Research By Neal H. Hooker, Elsa A. Murano
-Journal of Business Communication, Vol. 41, No. 2, 192-211 (2004)DOI: 10.1177/0021943603261748© 2004 Association for Business Communication
Consumer Reaction to Negative Publicity
Effects of Corporate Reputation, Response, and Responsibility for a Crisis Event by Dwane Hal Dean
-Hygiene for Management Richard A. Sprenger Highfield Publications 1993.
-Legal fees
-Higher insurance costs
-Lost market share and profits
-Negative publicity
-Closure of food premises by local authorities
-Incurred costs from internal investigation
-Incurred costs from cleaning, decontamination and replacement of equipment
References:
-http://books.google.com/books?hl=en&lr=&id=kexwWKbS6b4C&oi=fnd&pg=PA121&dq=consequences+of+food+poisoning+on+company&ots=LqpZWpc9pp&sig=4l90c3YJHOHWsknZPcyjpfmFpSA#PPP1,M1
Interdisciplinary Food Safety Research By Neal H. Hooker, Elsa A. Murano
-Journal of Business Communication, Vol. 41, No. 2, 192-211 (2004)DOI: 10.1177/0021943603261748© 2004 Association for Business Communication
Consumer Reaction to Negative Publicity
Effects of Corporate Reputation, Response, and Responsibility for a Crisis Event by Dwane Hal Dean
-Hygiene for Management Richard A. Sprenger Highfield Publications 1993.
Importance of QA and QC
Quality control includes the inspection, testing and monitoring of raw materials, process control and finished products control. Quality assurance is more elaborate. It describes control, evaluation and audit of a food processing system. Other than monitoring QA programs, it includes other actions that prevent food safety hazards and quality defects. It includes documents that describe operations and activities that pertain to food quality and safety. This documents include product-specific manufacturing (PSM) documents, general manufacturing operation (GMO documents, quality control analytical (QCA) documents, good manufacturing practices (GMP) documents etc.
Benefits of proper QA/QC includes: reduction in consumer complaints, consistency of product both within and across manufacturing locations, and cost savings with decreases in rejected product.
References:
-http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T6T-45YG5P7-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b4e9cf8f5e41536072004be1f7644ee7
-Quality Assurance for the Food Industry: A Practical Approach By J. Andres Vasconcellos CRC Press 2004
-Quality Control In The Food Industry Vol. 1 S.M. Herschdoerfer Academic Press 1989
-Total Quality Assurance For The Food Industries Second Edition Wilbur A. Gould and Ronald W. Gould CTI Publications, Inc 1993
-Food Quality Assurance Principles and Practices Inteaz Alli CRC Press 2004
Benefits of proper QA/QC includes: reduction in consumer complaints, consistency of product both within and across manufacturing locations, and cost savings with decreases in rejected product.
References:
-http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T6T-45YG5P7-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b4e9cf8f5e41536072004be1f7644ee7
-Quality Assurance for the Food Industry: A Practical Approach By J. Andres Vasconcellos CRC Press 2004
-Quality Control In The Food Industry Vol. 1 S.M. Herschdoerfer Academic Press 1989
-Total Quality Assurance For The Food Industries Second Edition Wilbur A. Gould and Ronald W. Gould CTI Publications, Inc 1993
-Food Quality Assurance Principles and Practices Inteaz Alli CRC Press 2004
Regulations on levels of preservatives, microbiological and chemical limits
From Singapore Sale of Food Act
1.E. coli or other pathogens------<20 cfu/ml
2.Total Plate Count--------------<100,000 cfu/ml
3.Pesticide residue---------------According to 9th Schedule
4.Heavy metals, arsenic , lead and copper---According to 10th Schedule
5.Mercury----------------------------------<0.05ppm
6.Tin---------------------------------------<250ppm
7.Cadmium---------------------------------<0.2ppm
8.Antimony---------------------------------<1ppm
9.Selenium----------------------------------<1ppm
10.Food additives---------According to JECFA
1.E. coli or other pathogens------<20 cfu/ml
2.Total Plate Count--------------<100,000 cfu/ml
3.Pesticide residue---------------According to 9th Schedule
4.Heavy metals, arsenic , lead and copper---According to 10th Schedule
5.Mercury----------------------------------<0.05ppm
6.Tin---------------------------------------<250ppm
7.Cadmium---------------------------------<0.2ppm
8.Antimony---------------------------------<1ppm
9.Selenium----------------------------------<1ppm
10.Food additives---------According to JECFA
Monday, March 31, 2008
purpose of MVP packaging
abstracted from: http://missourifamilies.org/quick/foodsafetyqa/qafs346.htm
Why is it important to package foods for freezing in moisture-vapor-proof or resistant materials?
Freezer packaging needs to be moisture-vapor-proof or resistant to keep food from drying out, and to preserve nutritive value, flavor, texture, and color.
What are moisture-vapor-proof materials and moisture-vapor- resistant materials?
Rigid plastic containers, heavy-duty aluminum foil and glass jars are moisture-vapor-proof.
Why is it important to package foods for freezing in moisture-vapor-proof or resistant materials?
Freezer packaging needs to be moisture-vapor-proof or resistant to keep food from drying out, and to preserve nutritive value, flavor, texture, and color.
What are moisture-vapor-proof materials and moisture-vapor- resistant materials?
Rigid plastic containers, heavy-duty aluminum foil and glass jars are moisture-vapor-proof.
Safe Food Storage Times
abstracted from: http://www.azdhs.gov/phs/oeh/fses/sfstt.htm
Shelf Storage
Store foods in the coolest cabinets or pantry and away from appliances which produce heat. Warm and humid climates shorten the shelf-life of foods.
Refrigerator Storage
Store food in the home refrigerator from 34 to 40°F (1 to 3°C). Foods spoil rapidly above 40°F (3°C).
Freezer Storage
The best temperature for frozen food storage is at 0°F (-17°C). The temperature should not reach higher than 5°F (-15°C). Check the temperature with a thermometer. Package frozen foods in moisture-vapor-proof (MVP) packages or freezer containers.
Shelf Storage
Store foods in the coolest cabinets or pantry and away from appliances which produce heat. Warm and humid climates shorten the shelf-life of foods.
Refrigerator Storage
Store food in the home refrigerator from 34 to 40°F (1 to 3°C). Foods spoil rapidly above 40°F (3°C).
Freezer Storage
The best temperature for frozen food storage is at 0°F (-17°C). The temperature should not reach higher than 5°F (-15°C). Check the temperature with a thermometer. Package frozen foods in moisture-vapor-proof (MVP) packages or freezer containers.
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