Food chemical safety

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Food chemical safety
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Chemical contaminants in foods

• Characteristics
• They are not added intentionally added to food.
• Contamination can happen at one or more stages in
  food production.
• Illness is likely to result if consumers ingest
  enough of them.
• The above differentiate from other chemicals in
  food such as vitamins and additives.

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Examples of chemical contaminants

• Pesticides
• Herbicides
• Fungicides
• Veterinary drugs

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Pesticides

• eat your fruits and vegetables is one of the
  recommendations for a healthy diet.
• Use of pesticides and chemicals to protect fruits
  and vegetables against insects and pests, and
  moulds.
• Correct and responsible use of pesticides can
  enhanced yield and safety of these produce.

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Use of pesticide

• Must follow the limits sets by the Ministry for
  use on food commodity, and the safe amount of
  pesticide residue that may be present at the
  point of sale.
• The safe residue level conform with the
  international standards set by Codex Alimentarius
  Commision.

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Potential hazard?

• Pesticide residue.
• Contamination of surface and ground water.
• Persistent pesticide not degradable are removed
  from the registration list.

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Acceptable Daily Intake (ADI)

• ADI is a measure of toxicity.
• Calculated from a known toxicological effect of a
  chemical (e.g. pesticide), example increased
  serum glutamate pyruvate aminotransferase (SGPT)
  in dicator of liver damage.
• The dose of the pesticide below the point at
  which the defined toxicological effect occurs in
  animal studies is determeined (NO Observable
  Adverse Effect Level NOAEL).
• This is the maximum dose that can be consumed
  without any adverse effect resulting.
• ADI exceeds the level is rare, but cases of
  lindane in milk (UK in1996) and chlormequat in
  pears in 1999.

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Maximum Residue Level (MRL)

• MRL is not a toxicological parameters but a
  trading standard set by national and
  international authorities (e.g. Codex
  Alimentarius) to ensure that residues are
  controlled in world food trade.
• MRL is the pesticide residue level in particular
  food following its production according to Good
  Agricultural Practices (GAP) i.e. apply pesticide
  at the right time and according to label
  directions, appropriate withdrawal period (time
  necessary between application of pesticide and
  harvest) the crop is harvested and residue
  determined.
• If the level of pesticide exceed the MRL, the
  crop has not been grown according to GAP and the
  product not permitted to be sold, imported or
  exported.

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• Exceeded the MRL has no health implication, but
  the farmer has breached the national or
  international regulations and is liable for
  prosecution.
• Exceeding the MRL is more common.

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• Pesticides must be in harmony with non target
  pests and environment.
• Those broad-spectrum pesticides and have long
  residual effect were either removed from the
  market or restricted usage.
• The regulatory body is Pesticide Board of
  Malaysia under the preview of the Ministry.

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Pesticides withdrawn or partially banned by the
Pesticide Board of Malaysia

• Aldrin withdrawn by the parent company
• Diledrin ------do-----
• Benomyl -------do-----
• Chlordane total ban
• DDT total ban
• Heptochlor total ban
• Penthachlorophenate partial ban not allowed for
  paddy
• Endosulphan partial ban not allowed for cocoa
  and pepper
• Lindane (gamma-BHC) partial ban allowed for
  palm oil and coconut only
• (total 17 pesticides)

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Pesticides not allowed for use on vegetables

• Some organophosphate pesticides, e.g.
  methamidophos and monocrotophos, were registered
  for use in vegetables but after review by the
  Pesticide Board, they have been banned based on
  their residue or toxicology problems.
• All pesticides use in Malaysia must be
  registered.
• Comply the Pesticide Act 1974 and Food Act 1985,
  for the registration, production, management and
  application of pesticides.

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DDT organochlorine(1,1-(2,2,2-trichloroethylid
ene)bis(4-chlorobenzene)

• Dr. Paul Muller, a Swiss chemist won an Nobel
  Prize in Medicine in 1948 for DDT, replacing
  extremely dangerous chemicals for pest control
  (arsenic, lead and mercury).
• Effective against mosquitoes causing malaria,
  kill lice, improve health in Sri Lanka.
• 1964 use of DDT was discontinued in Sri Lanka,
  and coincide with publication of Carsons Silent
  Spring.
• Attack on DDT
• cause thin egg shells. (ii) DDT is so stable and
  could never be eliminated from the environment.
  Safe for human? Cancer? (lipid solubles)
• Repeated administration of DDT to animals results
  in tremor, incoordination, muscular twitching and
  weakness.
• DDT is excreted in urine.

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Organophosphate (OPs)

• Oldest synthetic pesticides.
• Common names organic phosphates, phosphate
  insecticides, phosphorus esters or phosphoric
  acid esters.
• Genarally speaking they are most toxic to
  vertebrate animals.
• Mode of action is similar to nerve gas (potent
  cholinesterase).
• Attack nerve, death as a result of respiratory
  failure.
• e.g. malathion, parathion.
• easily metabolized by esterase,low mammalian
  toxicity.
• Residues in food products do not normally result
  in exposure sufficient to lead to health problems
  in humans.
• Pyrethroids green pesticide from chrysanthemum
  (pyrethrum).

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Other insecticides

• Carbamates similar to Ops, water solubles,
  contaminated water.
• mode of action similar to Ops cholinesterase
  inhibitors.
• Cyclodiene e.g. aldrin and dieldrin, stable in
  soil and relative stable to uv of sunlight. Use
  to control soil insects. Mode of action is
  neurotoxicity.

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Herbicides

• Weed killers.
• Trace residues present in final food products.
• Chlorophenoxy acid esters 2,4-D and 2,4,5-T
• No apparent adverse effects on human and animals.
• The 2,4,5-T used in Agent Orange contains
  excessive amounts of tetrachrodioxin, suspected
  toxic impurity.
• Bipyridyliums paraquat and diquat.
• On contact plant tissues are quickly damaged.
• Cases of accidental or suicidal fatalities from
  paraquat poisoning.

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Fungicides

• Chemicals used to kill or stop the development of
  fungi.
• To treat plants, roots,seeds

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Industrial and environmental contaminants

• Most do not pose threats to human, but some
  certain incidences have indicated that they can
  be a potential hazard.

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• Halogenated hydrocarbons polychlorinated
  Biphenyls (PCBs) or trade name Aroclor first
  synthesise in1881.
• Uses insulating fluids in electrical industries,
  food packaging made from recycled paper, paints,
  lubricants, insulating tapes, fireproofing
  materials, and ink.
• Considerable resistant to acids, bases, high
  temperature, electrical current and is
  nonflammable.
• Safety no significant health threats to human.

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Dioxin

• TCDD (tetrachlorodibenzo-p-dioxin) are among most
  potent toxicants known, chemically very stable
  and binds strongly to to solids or particulate
  matter in soil, is lipophilic but sparingly
  soluble in water or organic liquids.
• LD50 for TCDD in guinea pig is under 1 mg/kg
  hamster is more than 10g/kg.
• Toxicity affect the kidney and skin, promoter of
  carcinogenesis and is a carcinogen. Liver
  tumors, tumors of the mouth, nose and lung have
  been found.
• Three times more potent than aflatoxin B1.
• In rhesus monkeys, TCDD is fetotoxic, resulting
  in higher levels of abortion and death in
  pregnant females.
• Human exposure no fatalities, toxic effects
  include fatigue, affect peripheral nervous system
  and liver toxicity.

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Heavy metals

• Mercury exists in many forms.
• metallic mercury, inorganic mercury compounds or
  salts, organic mercury compounds.
• Nervous system is very sensitive to all forms of
  mercury. Exposure to high levels of metallic,
  inorganic or organic mercury can permanently
  damage the brain, kidneys and developing fetus.
• Mercury chloride and methyl mercury are possible
  human carcinogens.
• Children are more sensitive to
• Children are more sensitive to mercury than are
  adults, can be passed through breast milk.

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Mercury level in water

• FDA maximum permissible level of 1ppm methyl
  mercury in seafoods.
• EPA mercury in drinking water 2 ppm.

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Lead

• Previously, this heavy metal was found in a
  variety of consumer products (lead-based paints,
  antiknock petrol, lead-glazed glasses, lead water
  pipes, lead glazes, lead solders).
• Lead poisoning is normally due to occupational
  situations.
• Children are most affected, lead absorption in
  children is about 40, adult 10, highest in the
  bone.
• Anemia, neurological disorders in developing
  children brains, can pass from placenta to fetus.
• Elimination or minimize exposures.

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Cadmium

• Cadmium in food is as inorganic cadmiun salts.
  Organic cadmium is unstable.
• In Japan, chronic cadmium intoxication over 12-yr
  period occurred in some population that consumed
  rice contaminated with cadmium because of
  pollution. Painful disease called itai itai
  meaning ouch ouch bone disease, with symptoms
  of skeletal deformation and multiple fractures.
• Cadmium stays in the liver and kidneys.
• Breathing air with very high levels of cadmium
  can severely damage the lungs and cause death.

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Arsenic

• Found as inorganic and organic compounds. In
  foods, drinking water, wine and other sources.
• Used widely in manufacture of glass to remove
  green colour cause by impurities.
• Previously arsenic is used to treat syphilis
  until penicillin and other sulfa drugs were
  developed.
• Arsenic is abundant in seafoods, but in an
  organic form, not toxic, rapidly absorbed and
  excreted in the urine and bile.
• Classical syndromes of chronic arsenic exposure
  include hyperkeratosis, corns and warts on the
  feet and hands.
• May be indirect carcinogen.
• 10 to 50 ppb may be necessary to maintain
  homeostasis of the body, used successfully to
  treat acute promyelocytic leukemia (APL).
• Standard in drinking water is 10ppb.

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Contaminants of Industrial and Environmental
Origin
CHEMICAL Polychlorinated biphenyls Dioxin Mercury Lead Cadmium Radionuclides SOURCE Electrical appliances Impurity Chlor-alkali Vehicle emission, smelting, paint, glazes, solder Sludge, smelting Accidental release ASSOCIATED FOOD Fish, animal fat Fish, milk, beef fat Fish Vegetables, canned food, canned dish, acidic food Grains, vegetables, meat, molluscs Fish, mushrooms
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Contaminants of Biological Origin(Inherent Plant
Food Toxicants)
CHEMICAL Oxalates Glycoalkaloids Cynide Phytohaemagglutinin Various carcinogens ASSOCIATED FOOD Tea White potato (solanine) Cassava, Lima beans Red kidney beans and other beans Herbs, spices
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Contaminants of Biological OriginMycotoxins
CHEMICAL Aflatoxin Trichothecenes Ochratoxin A Ergot alkaloids Patulin Zearalenone SOURCE Aspergillus flavus and A. parasiticus Mainly Fusarium spp A. ochraceous Claviceps purpurea Penicillium claviforms Fusarium spp ASSOCIATED FOOD Corn, peanuts, copra, milk Cereals and other foods Wheat, corn, barley Barley, wheat Apples and other fruits Cereals, oils, starch
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Minimum Water Activity for Growth of Toxigenic
Moulds
Mould Aspergillus flavus Aspergillus ochraceus Penicillium griseofulvum Minimum Aw 0.81 0.78 0.83
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Target Organs of Some Mycotoxins
Mycotoxin Aflatoxin Ochratoxin Trichothecenes Ergot alkaloids Zearalenone Target Liver Kidney Mucosa Peripheral vascular system Uro-genital tract
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Regulatory Limits for Mycotoxins in Foods
Mycotoxin Aflatoxins B and G Aflatoxin M1 Ochratoxin A Deoxynivalenol Patulin Zearalenone Limit (ppb) 0 - 50 10 1000 0 0.5 1 300 1000 4000 20 50 30 - 1000 Commodities All foods Animal feeds Milk, dairy Rice, corn, barley, beans, pork kidney Wheat Apple juice All foods
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Regulatory Limits for Aflatoxins in Some Asian
Countries
Country China Hong Kong India Japan Malaysia Philippines Singapore Sri Lanka Thailand Limit (ppb) 50 20 15 30 10 10 20 Absence 30 20 Commodity Peanuts Peanuts Other foods All All All All All Peanuts All
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Other Toxicants of Biological Origin
Chemical Ciguatera Shellfish toxins Paralytic, neurotoxic, diarrheic and amnesic Pyrrolizidine alkaloids Histamine Source Dinoflagellates Dinoflagellates Various toxic plants Spoilage bacteria Associated Food Tropical fish Shellfish Cereals, honey Fish, cheese
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Contaminants Produced During Processing

• Polynuclear aromatic hydrocarbons
• Heterocyclic amines, nitropyrenes
• Nitrosamines
• Oxidized fats
• Ethyl carbamate (urethane)

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Improperly Used Agrochemicals

• Pesticides Organochlorine insecticides
• Organophosphorus insecticide
• Carbamate insecticides
• Other pesticides
• Animal Drugs Antimicrobials
• Growth promotants
• Anthelminthics
• Therapeutics
• Fumingants Fungicides Plant growth regulators
• Fertilizers Herbicides Rodenticides
• Nematocides Molluscicides Biotechnology

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Direct Food Additives(Improperly Used Additives)

• Anti-caking agents
• Antimicrobial agents
• Antioxidants
• Colours
• Curing and pickling agents
• Emulsifiers
• Enzymes
• Firming agents
• Flavour enhancers
• Flavourong agents
• Humectants
• Leavening agents

• Release agents
• Non-nutritive sweeteners
• Nutrient supplements
• Nutritive sweeteners
• Oxidizing and reducing agents
• pH control agents
• Propellants and gases
• Sequestrants
• Solvents and vehicles
• Stabilizers and thickners
• Surface-active agents
• texturizers

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Indirect Food Additives(improperly used)

• Processing Aids
• Ion-exchange resins, filter aids
• Enzyme preparation
• Microorganisms
• Solvents, lubricants, release agents
• Specific function additives
• Food Contact materials
• Utensils
• Working surfaces
• Equipment
• Packing materials
• Metals, plastics, paper, wood, etc.
• Cleaning Agents
• Detergents
• Sanitizers

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Adultrants

• An adulterant is a substance found within
  substances(e.g. food, beverages, fuels), although
  not allowed for legal or other reasons.
• The addition of adulterants is calleda
  dulteration. An adulterant is distinct from, for
  example, permitted food additives. There can be a
  fine line between adulterant and additive
  chicory may be added to coffee to reduce the
  costthis is adulteration if not declared, but
  may be stated on the label.
• e.g
• Borax
• Boric acid
• Formaldehyde
• Unapproved colouring agents.

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Monitoring Points for Chemical Hazards

• Point source
• Environmental compartments
• Primary production
• Import/export
• Production and processing
• Consumer level
• Biomonitoring

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Criteria for Establishing Priorities

• Severity of potential effects on health
• Levels in individual foods and the diet
• Size and susceptibility of the exposed population
• Significance in domestic and international trade
• Nature and cost of management options

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Chemical Hazards in the Home

• Contaminated food and water
• Metal cookware contaminated with heavy metals
• Ceramic serving dishes with toxic glazes
• Leaded crystal used with acid foods
• Miscellaneous home-use chemicals

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Chemical Hazards in Food
Areas of Concern
Exposure
Toxicity
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Potential Physical Hazards

• Glass
• Slime or scum
• Metal
• Bone
• Plastic
• Stones and rocks
• Capsules or crystals
• Pits or shell
• Wood
• Paper

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Distribution of Complaints of Foreign Objects in
Foods

• Soft drinks 19
• Infant foods 16
• Bakery 14
• Chocolate and cocoa products 7
• Fruits 7
• Cereals 5
• Vegetables 4
• Fish 3
• Others 25

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Possible Control Measures

• Visual inspection
• Filters or sieves
• Magnets
• Separation by density
• Personnel precautions

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• Assignment search for literature for reports on
  interaction of selenium and heavy metals.

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