Egg quality: Chemical residues in respect to food safety

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

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