Secalim UMR1014, INRA, Oniris, 44307 Nantes, France.
Secalim UMR1014, INRA, Oniris, 44307 Nantes, France.
Food Res Int. 2018 Apr;106:1077-1085. doi: 10.1016/j.foodres.2017.12.017. Epub 2017 Dec 13.
Highly prevalent in poultry, Campylobacter is a foodborne pathogen which remains the primary cause of enteritis in humans. Several studies have determined prevalence and contamination level of this pathogen throughout the food chain. However it is generally performed in a deterministic way without considering heterogeneity of contamination level. The purpose of this study was to quantify, using probabilistic tools, the contamination level of Campylobacter spp. on chicken carcasses after air-chilling step in several slaughterhouses in France. From a dataset (530 data) containing censored data (concentration <10CFU/g), several factors were considered, including the month of sampling, the farming method (standard vs certified) and the sampling area (neck vs leg). All probabilistic analyses were performed in R using fitdistrplus, mc2d and nada packages. The uncertainty (i.e. error) generated by the presence of censored data was small (ca 1 log) in comparison to the variability (i.e. heterogeneity) of contamination level (3 log or more), strengthening the probabilistic analysis and facilitating result interpretation. The sampling period and sampling area (neck/leg) had a significant effect on Campylobacter contamination level. More precisely, two "seasons" were distinguished: one from January to May, another one from June to December. During the June-to-December season, the mean Campylobacter concentration was estimated to 2.6 [2.4; 2.8] log (CFU/g) and 1.8 [1.5; 2.0] log (CFU/g) for neck and leg, respectively. The probability of having >1000CFU/g (higher limit of European microbial criterion) was estimated to 35.3% and 12.6%, for neck and leg, respectively. In contrast, during January-to-May season, the mean contamination level was estimated to 1.0 [0.6; 1.3] log (CFU/g) and 0.6 [0.3; 0.9] log (CFU/g) for neck and leg, respectively. The probability of having >1000CFU/g was estimated to 13.5% and 2.0% for neck and leg, respectively. An accurate quantification of contamination level enables industrials to better adapt their processing and hygiene practices. These results will also help in refining exposure assessment models.
空冷后鸡胴体中弯曲杆菌污染水平的概率评估
弯曲杆菌在禽类中普遍存在，是食源性病原体，也是人类肠炎的主要病因。已有多项研究确定了该病原体在整个食物链中的流行率和污染水平。然而，这些研究通常是确定性的，没有考虑污染水平的异质性。本研究的目的是使用概率工具，定量评估法国几家屠宰场空气冷却后鸡胴体中弯曲杆菌属的污染水平。从一个包含截尾数据（浓度<10CFU/g）的数据集（530 个数据）中，考虑了几个因素，包括采样月份、养殖方式（标准与认证）和采样部位（颈部与腿部）。所有的概率分析均在 R 语言中使用 fitdistrplus、mc2d 和 nada 包完成。与污染水平的变异性（即异质性）（3 个对数或更多）相比，截尾数据的存在产生的不确定性（即误差）较小（约 1 个对数），这加强了概率分析并有助于解释结果。采样期和采样部位（颈部/腿部）对弯曲杆菌的污染水平有显著影响。更确切地说，区分了两个“季节”：一个是 1 月至 5 月，另一个是 6 月至 12 月。在 6 月至 12 月的季节，颈部和腿部的弯曲杆菌浓度估计值分别为 2.6[2.4；2.8]log（CFU/g）和 1.8[1.5；2.0]log（CFU/g）。颈部和腿部的>1000CFU/g（欧洲微生物标准的上限）的概率估计值分别为 35.3%和 12.6%。相比之下，在 1 月至 5 月的季节，颈部和腿部的污染水平估计值分别为 1.0[0.6；1.3]log（CFU/g）和 0.6[0.3；0.9]log（CFU/g）。颈部和腿部的>1000CFU/g的概率估计值分别为 13.5%和 2.0%。对污染水平的准确量化使工业界能够更好地调整其加工和卫生实践。这些结果还将有助于完善暴露评估模型。
