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|linkpage = Food Derived Hazards to Human Health - WikiVPH|linktext = Food Derived Hazards to Human Health
|linkpage = Veterinary Public Health|linktext = Veterinary Public Health
|pagetype = VPH
|pagetype = VPH
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#'''Growth Promoters'''<br>Growth Promoters are used amongst other things to increase production performance of animals and not for a health benefit to the animal or consumer. Commonly used Growth Promoters are Hormone-like compounds & antimicrobials. Growth Promoters Growth Promoters are not allowed in the EU but are in the USA & other countries. This has important trade implications.
#'''Growth Promoters'''<br>Growth Promoters are used amongst other things to increase production performance of animals and not for a health benefit to the animal or consumer. Commonly used Growth Promoters are Hormone-like compounds & antimicrobials. Growth Promoters Growth Promoters are not allowed in the EU but are in the USA & other countries. This has important trade implications.
##'''''Hormone-like growth promoters'''''<br>These include synthetic hormones (e.g.Diethylsibestrol), natural hormones (e.g. estradiol, Progesterone, Testosterone), fungal oestrogens (Zearalenone), Beta-agonists (Trenbolone) and thyreostatics. Risk associated with these compunds can be difficult to evaluate as administered natural hormones may be dificult to distinguish from endogenous hormones in animals & people. Also synthetic hormones given to young animals may not be detectable at time of slaughter.
##'''''Hormone-like growth promoters'''''<br>These include synthetic hormones (e.g.Diethylsibestrol), natural hormones (e.g. estradiol, Progesterone, Testosterone), fungal oestrogens (Zearalenone), Beta-agonists (Trenbolone) and thyreostatics. Risk associated with these compunds can be difficult to evaluate as administered natural hormones may be dificult to distinguish from endogenous hormones in animals & people. Also synthetic hormones given to young animals may not be detectable at time of slaughter.
##'''''Antimicrobial Growth Promoters'''''<br>Fed are low but continuous doses in feed they have been observed to cause increased growth rates. Although not understood the mechanism of action could be via suppressing disadvantagous intestinal microflora or direct anabolic effects of the drugs themselves. Virginamycin, bacitracin, polymyxin B & sulphonamides are commonly used. There used is strongly suspected of causing [[Antimicrobial Resistance - WikiVPH|Antimicrobial Resistance]].
##'''''Antimicrobial Growth Promoters'''''<br>Fed are low but continuous doses in feed they have been observed to cause increased growth rates. Although not understood the mechanism of action could be via suppressing disadvantagous intestinal microflora or direct anabolic effects of the drugs themselves. Virginamycin, bacitracin, polymyxin B & sulphonamides are commonly used. There used is strongly suspected of causing [[Antimicrobial Resistance]].
=Environmental Chemical Hazards=
=Environmental Chemical Hazards=
Often from an industrial source they include:
Often from an industrial source they include:
#'''Heavy Metals'''<br>(e.g. Lead, Arsenic, Mercury, Cadmium, Fluorine &Selenium)
#'''Heavy Metals'''<br>(e.g. Lead, Arsenic, Mercury, Cadmium, Fluorine &Selenium)
##'''''Lead'''''
##'''''Lead'''''-Lead can occur in animals grazing near smelting plants or from animals licking lead based paints or old car batteries. Lead then accumulates in the bones. Acute poisoning may result in high levels in the liver & kidneys. Chronic exposure may cause softening & cavitation of the CNS.
##'''''Arsenic'''''-Contamination of food animals with arsenic is typically due to exposure to arsenical herbicides, rodenticides or insecticides. Its accumulation in the liver & kidneys can lead to fatty degeneration. It also accumulates in the bones.
##'''''Mercury'''''-Rare cases of mercury poisoning have been due to animals being fed with grain treated with mercury-based anti-fungicides. The result is enlarged internal organs & petechiation). Inorganic mercury is also stored in the liver & kidneys, whereas organic mercury is more widely distributed. See [http://www.env.go.jp/en/chemi/hs/minamata2002/| Minamata disease]
##'''''Cadmium'''''-An increasing problem, high cadmium levels occur in animals grazing pasture irregated with aerobically digested sludge. Contamination of shell fish & fish also occur as cadmium may contaminate water. It accumulates in the bidy tissues & may cause kidney failure. Prolonged accumulation is required to reach toxic levels.
=Food Additives=
=Food Additives=
This refers to chemicals deliberately added to foods in a controlled manor & at a level that is judged as posing no significant health risk. However, uncertain circulmstances some food additives may present a health risk. They may be curing agents, smoke compunds, antioxidants, preservatives or agents improve sensory qualities.
#'''Additives to improve Sensory Qualities'''<br>There are many food additives for food that do not offer any food safety benefits & are added to improve the sensory qualities (Organoleptic qualities) of the food. Possible health risks of these additives are poorly defined but some associations have been put forward (e.g. hyperactivity in children). <br>Organoleptic qualities that they may afffect are colour (e.g. dyes), emulsifiers, sweetners (e.g. saccharin, acesulfame k, aspartame) & flavour enhancers (e.g. Sodium Glutamate).
#'''Nitrites & Nitrates'''<br>Nitrogen Dioxide reacts with myoglobin in meat to give it an attractive, bright red colour. Nitrates helps to inhibit the growth of clostridial spores in cured meats (e.g. sausages) & provide the cured flavour. Nitrites are toxic if concentrations are too high (so levels are monitored), it may combine with the blood pigment Haemoglobin to form nitrosohaemoglobin. In addition, the nitrites may react with amines in the meat to form Nitrosamine compounds that are carcinogenic. This small risk is seen to be outweighed by that health benefits of inhibiting ''C.botulinum''. Nitrites levels of tobacco smoke & some vegetables (e.g. spinach) are many times higher than in cured meats. See [[Preservation Methods]].
#'''Polyphosphates'''<br>Polyphosphates are added to meats to increase the meat proteins ability to bind water. This improves texture & increases the weight of the meat. THey could potentially cause a disturbance to the bodies calcium/phosphorus balance due to excess phosphorous intake. Children would be particuarly affected by this due to their rapid bone growth.
#'''Smoke'''<br>Smoke flavours are used to improve the organoleptic properties of some foods. Some compounds from smoke have antimicrobial properties (e.g.organic acids & phenols) and some smoke compounds are carcinogenic. Polycyclic aromatic hydrocarbons, such as 3,4 benzpyrene, are carcinogens produced when smoking at over 300◦C. A liquid smoke product is frequently used that has the toxic compunds removed but retains the compounds that improve organoleptic qualities.
#'''Plastic Packaging Compounds'''<br>Vinyl chloride monomers, that are carcinogenic, are used to produce Polyvinyl Chloride (PVC) plastic packages, that are safe/non-carcinogenic. However, in some circumstances the toxic monomers may still be present & could potentially transfer to the food. Other plastics, not intended for microwave use, if microwaved may react with fats in the food to produce toxic substances.
=Mycotoxins=
=Mycotoxins=
Some fungi produce toxins (Mycotoxins). If they grow in animal feeds any toxins then consumed may be present in products that come from these animals. Toxin producing fungi can also grow on some foods after harvest.<br> Mycotoxins of concern are Aflatoxins produced by ''Aspergillus flavus'' & ''A. parasiticus''. They are carcinogenic, affecting the liver. Ochratoxins produced by ''Penecillium spp.'' & some ''Aspergillus'' moulds and associated with pigs, affect the kidney.
=Marine Toxins=
=Marine Toxins=
Algae can produce toxins that may then accumulate in filter-feeding shellfish. Use of Phosphate-based fertilizers on farms may lead to algal blooms in costal waters (which may be seen as a red tide) leading to toxin production. These toxins may cause Paralytic Shellfish Poisoning (PSP) & other similar poisonings. Algal toxins are not destroyed by cooking. The clinical signs of PSP are numbness & tingling of the mouth & lips. Cranial nerves may be affected. Weakness of the limbs & paralysis progress & in some cases death may occur due respiratory failure due to paralysis of the respiratory muscles.
=Plant Toxins=
=Plant Toxins=
Some mushrooms & plants produce toxins. Examples are phytohaemagglutinin found in red kidney beans & deastroyed by heating & grayanotoxin found in honey produced from rhododendrons.
=Toxic Amines=
=Toxic Amines=
Toxic biogenic amnines, such as histamine & tyramine, are produced by the decarboxylation of free amino acids in any food. This can be caused by excessive consumption of amines or a deficiency of detoxifying enzymes (e.g. [[Monoamine Oxidase]]) in an individual. In the case of [[Scombroid poisoning]] Histadine in fish is converted into Histamine by [[Spoilage Bacteria]] before the fish is consumed.
This syptoms of Histamine intoxification are analygous to an allergic reaction i.e. rash, oedema & hypotension. Tyramine causes a rise in blood pressure possibly associated with migranes. Ripened cheeses, fermented sausages, red wine & chocolate are implicated as sources of tyramine poisoning.
=References=
See [[References - WikiVPH|References]]