Egg quality: Chemical residues in respect

to food safetyE. 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

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

Monitoring Comission Decission 97/747/EC

Directive 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

Monitoring Comission Decission 97/747/EC

Directive 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

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.

Undesirable (SCAN, 2003)

• Ions or elements – heavy metals– other trace elements, coming from feeds or

water– radionuclides

• Mycotoxins

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

Heavy metals

• In general levels are greater in albumin

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

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. Avg=0.0013- 0.005 mg/kg. Max= 0.01 mg/kg• PTWI= 0.005 mg/kg body weight/week.

– < 0.0033 mg/kg body weight/weeek as methyl mercury

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

Arsenic

• Skin lesions and neurological effects• Water, arsenicals (discontinued), pesticides

• As3 more toxic than As5

• In the egg, yolk/albumen=1/3• 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

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 > 5 mg F/day

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)

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

Arsenic 2

Lead 5

Fluorine 350

Mercury 0.1

Cadmium 0.5

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 > 10

days: 1000– 3H, 14C and 40K are excluded

Mycotoxins

• Eggs < 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.

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

Aflatoxin B1

• Residues when feed is 500 µg B1/kg feed but not at 300 µg B1/kg feed

• Transfer 4615:1 in yolk, 3846:1 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

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

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

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)

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

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.

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

Eggs are very valuable sources of nutrients

• Knowledge of risks is necessary to prevent contamination