Assessment of the Influence of Cooking Methods on Antibiotics Residues in Chicken Meat

Abstract

Unacceptable levels of antibiotics residues in chicken meat have dire implications for food safety and public health. This study assessed the influence of thermal processing methods on gentamicin and doxycycline residues in some tissues (liver, gizzard and skin) of broiler chicken exposed to a cocktail of both agents. Nine (9) one-day-old broiler chickens were reared under controlled conditions and divided into three experimental groups: a control group, an antibiotic-treated group that observed a withdrawal period, and an antibiotic-treated group without withdrawal period. Samples were subjected to boiling, roasting, and deep frying before residue analysis using gas chromatography. Considerable residue levels reduction of both agents were achieved by boiling (72.9 – 81.5%), deep-frying (68.1 – 92.4%) and roasting (61.1 – 91.1%) in the tissues. Kruskal-Wallis analysis indicated that these reductions were significant for deep-frying in the gizzard and skin (p = 0.014) and by boiling in the liver (p = 0.038) for gentamicin residues. Doxycycline residues were significantly reduced by roasting in the gizzard (p = 0.028); boiling in the liver (p = 0.01) and deep-frying in the skin (p = 0.027). Generally, liver antibiotic residues could be significantly reduced by boiling while gizzard and skin residues by deep-frying and roasting. Notably, thermal processing did not completely eliminate residues, especially in samples from the non-withdrawal group, emphasizing that cooking alone cannot substitute for proper withdrawal compliance prior to slaughter. The observation of withdrawal period of greater than 15 days is recommended as this could well complement the effort to reduce untoward antibiotic accumulation in consumers.