O'Keeffe M, Capurro E, Danaher M, Campbell K, Elliott C T
Food Safety Department, Ashtown Food Research Centre, Ashtown, Dublin 15, Ireland.
Food Addit Contam. 2007 Sep;24(9):923-34. doi: 10.1080/02652030701258778.
Investigations were undertaken to identify causes for the occurrence of high levels of the zootechnical feed additive nicarbazin in broiler liver at slaughter. The first investigation on 32 commercial broiler flocks involved sampling and analysis for nicarbazin (as dinitrocarbanilide, DNC) in liver from birds during a 3-10-day period after withdrawal of nicarbazin from their feed and before commercial slaughter. DNC residues in liver samples of broilers scheduled as being withdrawn from nicarbazin for > or =6 days ranged from 20 to >1600 microg kg(-1) (the specified withdrawal period for nicarbazin is 5 days and the Joint Expert Committee on Food Additives (JECFA) maximum residue limit (MRL) is 200 microg kg(-1) liver). Further on-farm investigations on 12 of these flocks, selected on the basis of the feeding system in use and the levels of DNC residues determined in liver, identified issues in feed management contributing to elevated residues in broiler liver. A significant correlation (0.81, p < 0.01, n = 10) between DNC residues in liver samples and in feed samples from the feeding pans was observed. The second investigation on 12 commercial broiler flocks involved sampling and analysis for DNC in liver samples and feed samples from feeding pans and from the feed mill at the three thinnings of birds for commercial slaughter. In the case of one flock, a clear relationship between nicarbazin in feed from the feed mill (10.5 mg kg(-1) DNC), in feed from the feeding pans (6.6 mg kg(-1) DNC) and in liver (583 microg kg(-1) DNC) at first thinning (9 days scheduled withdrawal from nicarbazin) was observed. Such a clear relationship was not observed in other cases, particularly at second and third thinnings, pointing to re-exposure of birds to nicarbazin late in the flock production cycle, probably from the litter. Guidelines outlining best farm practice to eliminate nicarbazin residues in poultry have been published in booklet and poster format for broiler producers and deal with feed system cleaning, feed bin management, feed deliveries, feed usage and records.
开展了调查，以确定肉鸡屠宰时肝脏中出现高水平畜牧饲料添加剂尼卡巴嗪的原因。对32个商业肉鸡群进行的首次调查包括，在停止向肉鸡饲料中添加尼卡巴嗪后3至10天且在商业屠宰前，对鸡的肝脏进行采样并分析其中的尼卡巴嗪（以二硝基卡巴苯胺，即DNC计）。计划停止使用尼卡巴嗪≥6天的肉鸡肝脏样本中的DNC残留量在20至>1600微克/千克之间（尼卡巴嗪的规定停药期为5天，食品添加剂联合专家委员会（JECFA）的最大残留限量（MRL）为肝脏中200微克/千克）。基于所使用的饲养系统以及肝脏中测定的DNC残留水平，对其中12个鸡群进行了进一步的农场调查，确定了饲料管理方面导致肉鸡肝脏中残留量升高的问题。观察到肝脏样本中的DNC残留量与料盘中饲料样本中的DNC残留量之间存在显著相关性（0.81，p<0.01，n = 10）。对12个商业肉鸡群进行的第二次调查包括，在肉鸡三次出栏用于商业屠宰时，对肝脏样本以及料盘和饲料厂的饲料样本进行采样并分析其中的DNC。对于一个鸡群，在首次出栏（计划停止使用尼卡巴嗪9天）时，观察到饲料厂饲料中的尼卡巴嗪（10.5毫克/千克DNC）、料盘饲料中的尼卡巴嗪（6.6毫克/千克DNC）与肝脏中的尼卡巴嗪（583微克/千克DNC）之间存在明确的关系。在其他情况下，尤其是在第二次和第三次出栏时，未观察到这种明确的关系，这表明鸡在鸡群生产周期后期可能从垫料中再次接触到尼卡巴嗪。已以小册子和海报形式为肉鸡生产者发布了概述消除家禽中尼卡巴嗪残留的最佳农场实践的指南，内容涉及饲料系统清洁、饲料仓管理、饲料运输、饲料使用和记录。
