Egg quality: Chemical residues in respect to food safety

1
Egg quality Chemical residues in respect to
food safety

• E. Esteve-Garcia1 and J.A. García-Regueiro2
• 1Department of Animal Nutrition, Centre de Mas
  Bové, Apartat 415, 43280 Reus, Spain
• 2Meat Technology Centre, Food Chemistry Unit,
  Granja Camps i Armet, 17121 Monells, Spain

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Egg is a very valuable source of nutrients

• Essential amino acids
• Vitamins (except vitamin C) and other interesting
  carotenoids (lutein, zeaxanthin)
• Essential minerals
• Linoleic and linolenic acid

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Monitoring Comission Decission
97/747/ECDirective 96/23/EC

• Sample should allow tracking
• Taken at farm level or at packing centre
• 12 eggs or more
• 1 sample per 1000 Tonnes of annual production.
  Minimum 200 samples.
• 30 taken at packing centres

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Monitoring Comission Decission
97/747/ECDirective 96/23/EC

• Groups tested
• 70 tested for groups A6, B1 and B2(b)
• A6 pharmacologically active substances for which
  no maximum levels can be fixed (banned)
• B1 antibacterial substances, including
  sulfonamides and quinolones
• B2 (b ) Anticoccidials, including nitroimidazoles
• 30 according to situation, but must include B3
  (a)
• Organochlorine compounds, including PCBs

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Limits

• Drugs MRLs in Unofficial consolidated version of
  Annexes I to IV of Council Regulation 2377/90.
  Updated 22/12/2004.
• Limits for pesticides. Directive 2002/32/CE.
• Limits for Dioxins. Directive 2001/102/CE.

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Undesirable (SCAN, 2003)

• Ions or elements
• heavy metals
• other trace elements, coming from feeds or water
• radionuclides
• Mycotoxins

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Undesirable (SCAN, 2003)

• Other organic contaminants including
• organochlorine compounds
• pesticides
• Dioxins
• other pesticides
• polychlorinated biphenyls
• brominated flame retardans
• mineral oil hydrocarbons
• Plant and natural plant products
• Drugs

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Heavy metals

• In general levels are greater in albumin

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Lead

• Chronic and cumulative
• Accidental contamination
• airborne deposition in plants.
• Drinking water. Soft waters and leaded pipes.
• Paints,
• Affects enzymes, anemia, renal toxicity,
  carcinogen, cardiovascular and neurobiological
  impact
• Levels are low in eggs (0.003 to 0.259 mg/kg in
  European surveys)
• PTWI 0.020-0.025 mg/kg body weight

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Mercury

• Chronic and cumulative
• Teratogenic and carcinogenic, damages CNS
• Organic is more toxic.
• Feeding seed grains treated with methylmercuric
  chloride to prevent insect infestation. 93 mg/kg
  in albumen and 5.8 mg/kg in yolk.
• Accidental contamination in Washington State in
  1979 by mercurial fungicides. Nowadays are banned
• Maximum EU 0.3 mg Hg/kg in calcium carbonate
• European survey. Avg0.0013- 0.005 mg/kg. Max
  0.01 mg/kg
• PTWI 0.005 mg/kg body weight/week.
• lt 0.0033 mg/kg body weight/weeek as methyl
  mercury

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Cadmium

• Toxicity long term exposure
• Teratogenic and carcinogenic, kidney, bones,
  neurotoxic
• Sources plants grown in Cd rich soils,
  impurities in minerals, drinking water
• Present in egg yolk. Transfer is low, retained in
  follicle walls.
• Low levels in eggs in surveys (0.001-0.01 mg/kg).
  
• PTWI 0.42 mg/person/week

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Arsenic

• Skin lesions and neurological effects
• Water, arsenicals (discontinued), pesticides
• As3 more toxic than As5
• In the egg, yolk/albumen1/3
• At increasing levels in feed a plateau is reached
  rapidly
• Low levels in eggs in surveys (0.001-0.006 µg/g).
  
• PTWI 0.015 mg/kg body weight/week

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Fluorine

• In phosphate supplements (should be
  defluorinated).
• Genotoxic, skeleton (bone fracture), dental
  fluorosis and hypomineralization of enamel.
• Transferred to eggshell.
• High F diets result in 0.4-1.0 mg F/kg fresh
  albumen, and 3.1-8.4 mg F/kg dry fat free yolk.
• Risk of bone effects gt 5 mg F/day

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Nitrates

• Present in water and vegetables
• Anaemia
• Nitrites in water. Formation of methaemoglobin
• Fast excretion in urine. No bioaccumulation.
• Little information in eggs. Content probably low?
  Low compared to other sources (water)

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Limits for feeds (mg/kg)EU (1999-2002)
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Radionuclides

• Transfer is higher than for other animal products
• Experience from Chernobyl accident 137Cs and
  131I from contaminated cereals.
• Countermeasures Iron (III) hexacyanoferrates
• U and Po in phosphates in Israel. Dose equivalent
  for all poultry products (70 of meat) is 0.04
  mSv/year.
• (According to ICRP individual doses of less than
  10 µSv/year are negligible)
• Limits according to Council Regulation (EURATOM)
  No 2218/89 (Bq/kg)
• 90Sr 125 131I 500 239Pu and 241Am 20 134Cs
  and 137Cs and all t1/2 gt 10 days 1000
• 3H, 14C and 40K are excluded

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Mycotoxins

• Eggs lt animal feeds. Unlikely acute toxicity
• Aflatoxin B1, M, ochratoxin A are carcinogenic
  and must be monitored.
• Fumonisin, Vomitoxin, and zearalenone found at
  very low levels or not found ata all when
  contaminated feeds are given to hens.

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Ochratoxin A

• No information in eggs of laying hens
• In Japanese quail there is transfer to eggs.
• Contribution of products of animal origin is not
  more than 3 of the burden

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Aflatoxin B1

• Residues when feed is 500 µg B1/kg feed but not
  at 300 µg B1/kg feed
• Transfer 46151 in yolk, 38461 in albumen
• In Japanese quail transfer is higher
• After 7 days withdrawal only traces in eggs
• Limit in feeds is 0.02 mg B1/kg feed
• Limit in eggs is 3 pg WHO-PCDD/F-TEQ/ g fat
• Maximum level based on ALARA

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T2 Toxin

• Inmunosupresive and carcinogenic
• 1 mg T2 for 8 days 0.9 µgT2/egg
• Limits in Israel and Russia 0.1 mg T2/kg feed

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Organochlorine pesticides

• Transferred to eggs in many cases
• Very persistent. DDT (metabolites) still can be
  found in eggs more than 25 years after use was
  discontinued.
• Banned for most applications in Europe and USA
  but still used in some third world countries
  Monitoring of eggs and feed ingredients
• Limits for complete feeds and supplemental fats
  see manuscript, adapted from EU 1999

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Brominated flame retardants

• Accumulated like PCBs. From landfill and industry
  emissions
• Transferred to eggs
• Weight loss, liver damage, inmunity and
  reproduction. Carcinogenic
• Banned in Europe.
• Survey in Catalonia (Spain) PBDEs 58.3-64.5 ng/kg
  of wet weight in eggs
• NOAEL is 0.15 mg/kg BW (WHO, 1994)

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Plant and natural plant products

• EU list of 1999 includes 17 plant species and 5
  natural products
• According to SCAN risk is low.
• Affect health of animals rather than the products
  derived from them

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Mineral oil hydrocarbons

• Carcinogen
• Accidental contamination of fats and oils from
  gas oils (C18-C35) or synthetic oils (C25 and
  beyond C45) by discharge of waste oils.
• FDA maximum in cereals is 100 mg/kg
• Survey in Switzerland in fats for animal feeds
  levels between 100 and 1000 mg/kg.
• In 1999 in the fat phase of eggs average 30
  mg/kg, and maximum 80 mg/kg.

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Prevention

• At farm level
• Good production practices.
• Control and traceability of feeds
• Wtihdrawal time for drugs
• Control of drinking water
• Feed
• Monitoring of ingredients. European legislation
• HACCP
• Traceability

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Eggs are very valuable sources of nutrients

• Knowledge of risks is necessary to prevent
  contamination