Clapham Maaike O, McElroy Dierdra, Mercer Melissa A, Kass Philip H, Tell Lisa A
Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States.
Laika Diagnostics, California Canine, Lathrop, CA, United States.
Front Vet Sci. 2025 Jul 21;12:1579933. doi: 10.3389/fvets.2025.1579933. eCollection 2025.
Canine olfaction has been used to detect drug residues across a variety of matrices as part of law enforcement efforts. As such, canine olfactory sample screening should hold promise as a potential tool for detecting drug residues in food products to support human food safety in resource limited settings or where sensitive analytical methods are not available for various matrices. The objective of this pilot study was to evaluate the ability of companion dogs undergoing low-frequency olfactory detection training to detect florfenicol and its metabolite, florfenicol amine (FA), in incurred residue goat milk samples.
Companion dogs ( = 8) of various breeds with prior odor detection experience were enrolled in a canine odor detection study for 9 weeks to detect florfenicol/FA that entailed once weekly testing sessions. Double-blinded testing was performed in two phases. Study phase 1 consisted of 11 florfenicol/FA-contaminated goat milk samples (combined [florfenicol + FA] concentrations ranging from 17.44-1443.30 ppb) with 2 distractors, items that might distract the dog while working, per run presented to = 8 dogs. For study phase 2, the highest performing dogs ( = 3) from study phase 1 were tested with low concentration (<20 ppb) samples ( = 11) that were identified as being positive using a rapid residue detection test. Performance metrics, including accuracy, sensitivity, and specificity, were assessed across sample drug concentration categories.
For study phase 1, mean detection accuracy, sensitivity, and specificity were 0.80 [95% confidence interval (CI) (0.74-0.86), 0.70 (95% CI 0.65-0.76), and 0.86 (95% CI 0.82-0.88)], respectively. Sensitivity increased with higher drug concentrations, ranging from 0.38 at 17.96 ppb to 0.96 at 1443.30 ppb. Study phase 2 accuracy, sensitivity, and specificity were 0.88 (95% CI 0.85-0.91), 0.82 (95% CI 0.73-0.88), and 0.91 (95% CI 0.86-0.94), respectively. False positives were most often associated with blank goat milk.
Companion dogs undergoing low-frequency olfactory odor detection training were able to detect florfenicol/FA residues in goat milk with high specificity, particularly at high concentrations. However, sensitivity at low concentrations was limited. While canine olfactory detection does not appear to be suitable as a confirmatory method for companion dogs with low training commitments, this pilot study demonstrates its potential as an initial screening tool, particularly in resource-limited settings. Future research is needed to refine training protocols and assess performance under field conditions.
作为执法工作的一部分，犬类嗅觉已被用于检测各种基质中的药物残留。因此，犬类嗅觉样本筛查有望成为一种潜在工具，用于检测食品中的药物残留，以支持资源有限环境或无法使用各种基质敏感分析方法的地区的人类食品安全。这项初步研究的目的是评估接受低频嗅觉检测训练的伴侣犬在含有氟苯尼考及其代谢物氟苯尼考胺（FA）的山羊奶样本中检测氟苯尼考及其代谢物的能力。
将8只具有先前气味检测经验的不同品种伴侣犬纳入一项为期9周的犬类气味检测研究，以检测氟苯尼考/FA，每周进行一次测试。双盲测试分两个阶段进行。研究阶段1包括11个受氟苯尼考/FA污染的山羊奶样本（氟苯尼考+FA的组合浓度范围为17.44 - 1443.30 ppb），每次测试向8只犬展示2个干扰物，即可能在犬工作时分散其注意力的物品。对于研究阶段2，对研究阶段1中表现最佳的3只犬用低浓度（<20 ppb）样本（11个）进行测试，这些样本使用快速残留检测试验被鉴定为阳性。跨样本药物浓度类别评估了包括准确性、敏感性和特异性在内的性能指标。
对于研究阶段1，平均检测准确性、敏感性和特异性分别为0.80 [95%置信区间（CI）（0.74 - 0.86）]、0.70（95% CI 0.65 - 0.76）和0.86（95% CI 0.82 - 0.88）。敏感性随药物浓度升高而增加，范围从17.96 ppb时的0.38到1443.30 ppb时的0.96。研究阶段2的准确性、敏感性和特异性分别为0.88（95% CI 0.85 - 0.91）、0.82（95% CI 0.73 - 0.88）和0.91（95% CI 0.86 - 0.94）。假阳性最常与空白山羊奶相关。
接受低频嗅觉检测训练的伴侣犬能够以高特异性检测山羊奶中的氟苯尼考/FA残留，尤其是在高浓度时。然而，低浓度时的敏感性有限。虽然犬类嗅觉检测似乎不适合作为训练投入较少的伴侣犬的确证方法，但这项初步研究证明了其作为初始筛查工具的潜力，特别是在资源有限的环境中。未来需要开展研究以完善训练方案并评估野外条件下的性能。
