The definition of egg covers the unshelled eggs, which are obtained from “Gallus gallus domesticus” species of chicken and are suitable for directly putting into use of humans or for preparing egg products by processing, other than broken, incubated, or cooked eggs
1.
Turkey ranks 9th in the world production of chicken eggs. According to the data of Turkish Statistical Institute (TUİK), Turkey’s total egg production in year 2019 was 1.1 million tons (1.1 billion units). In year 2018, the total number of organic egg production was 1.250.000. The egg consumption per capita in our country in year 2019 was 214, while it was 333 in Japan, 307 in China, 305 in Russia, and 280 in Argentina 2.
The provisions of the Regulation on Maintaining the Minimum Standards for Protecting the Layer Hens are taken as basis 1,3. Before the company and coop numbers, the code of cultivation method is automatically assigned as 0: for organic cultivation, 1 for free range cultivation, 2 for cultivation in coop without cage, and 3 for cultivation in coop with cage (i.e.: 0TR060000060000-01 for organic cultivation). The date of laying might be labeled on the A-Class eggs. The code of cultivation method and the company and coop numbers are written in the coop or in the sorting or packaging facility of the same company. The A-Class egg, on which the code of cultivation method and the numbers of company and coop are not written, cannot the introduced to the market in wholesale or retail form. The code of cultivation method is explained in the label info of A-Class egg (Example: 0: Organic cultivation) 1.
Antibiotics are pharmacologically active materials that are widely used in veterinary practice in order to cure and prevent diseases or accelerate the healing process. However, the unconscious use of antibiotics (i.e.: unlicensed drug use) and not following the instructions on the label cause the problem of residuals on the tissues and organs having nutrient value and the foods obtained from them (meat, milk, offal, egg, honey) 4-6.
Since the poultry industry is an important protein source for the human, cultivation and production of healthy broiler and layer hens is of significant importance. For this reason, the use of antibiotics for curing, protecting, or growth-supporting purposes is very wide in the poultry industry 7. The tetracycline-group antibiotics, especially tetracycline, chlortetracycline, and doxycycline are the antimicrobial agents that are preferred by veterinary physicians for the poultry thanks to their wide spectrum of activity and low costs 8. Besides their important benefits, like many other antibiotics, the tetracycline agents may also cause problems such as allergic reactions, bacterial resistance, liver damage, tooth yellowing, and gastrointestinal disorders among the consumers since the main compounds and degradation products are found in the animal products 9.
Tetracycline is used in chickens and turkeys for treating the chronic respiratory disease (CRD), blue comb, coryza, cholera, pullorum, infectious synovitis and sinusitis, hemorrhagic septicemia, and various streptococcus and staphylococcus infections. Considering the regulations in our country, the washout period for tetracycline residuals was set to be 7 days for poultry meat and 14 days for egg 10. In Turkey, there are two tetracycline-containing medications licensed for veterinary medicine and one of them is used in poultry 11.
In organic farming, the use of chemically synthesized veterinary medical products or antibiotics as preventive agents is prohibited. However, in case of any compulsory situation, the controlled use of these agents is allowed. In order for a product to be classified as organic, the extraction period (half-life) of medication is taken into consideration 1.
Precise determination of tetracycline residues in animal foods is very important for public health. The European Union (EU) commission has reported the maximum residue limit (MRL) of 200 μg/kg of tetracycline group antibiotics in poultry, chicken tissues and eggs. Prepared by the Ministry of Agriculture and Forestry within the framework of harmonization with the EU commission; In the Turkish Food Codex Regulation on Classification of Pharmacologically Active Substances That May Be Found in Animal Food and Maximum Residue Limits, the MRL value for tetracyclines in eggs offered for consumption is determined as 200 μg/kg 3,12.
Within the scope of the present study, 60 egg samples produced as "coded and without code" according to the cultivation method in varying quality classes were examined in terms of tetracycline residues. The results obtained were analyzed in terms of food safety and public health by considering the standard values.