Maes Sharon, Huu Son Nguyen, Heyndrickx Marc, Weyenberg Stephanie van, Steenackers Hans, Verplaetse Alex, Vackier Thijs, Sampers Imca, Raes Katleen, Reu Koen De
1 Technology and Food Science Unit, Flanders Research Institute for Agriculture, Fisheries and Food, Brusselsesteenweg 370, 9090 Melle, Belgium.
2 Department of Industrial Biological Sciences, Faculty of Bioscience Engineering, Ghent University-Kortrijk, Graaf Karel de Goedelaan 5, 8500 Kortrijk, Belgium.
J Food Prot. 2017 Dec;80(12):2022-2028. doi: 10.4315/0362-028X.JFP-17-210.
Biofilms are an important source of contamination in food companies, yet the composition of biofilms in practice is still mostly unknown. The chemical and microbiological characterization of surface samples taken after cleaning and disinfection is very important to distinguish free-living bacteria from the attached bacteria in biofilms. In this study, sampling methods that are potentially useful for both chemical and microbiological analyses of surface samples were evaluated. In the manufacturing facilities of eight Belgian food companies, surfaces were sampled after cleaning and disinfection using two sampling methods: the scraper-flocked swab method and the sponge stick method. Microbiological and chemical analyses were performed on these samples to evaluate the suitability of the sampling methods for the quantification of extracellular polymeric substance components and microorganisms originating from biofilms in these facilities. The scraper-flocked swab method was most suitable for chemical analyses of the samples because the material in these swabs did not interfere with determination of the chemical components. For microbiological enumerations, the sponge stick method was slightly but not significantly more effective than the scraper-flocked swab method. In all but one of the facilities, at least 20% of the sampled surfaces had more than 10 CFU/100 cm. Proteins were found in 20% of the chemically analyzed surface samples, and carbohydrates and uronic acids were found in 15 and 8% of the samples, respectively. When chemical and microbiological results were combined, 17% of the sampled surfaces were contaminated with both microorganisms and at least one of the analyzed chemical components; thus, these surfaces were characterized as carrying biofilm. Overall, microbiological contamination in the food industry is highly variable by food sector and even within a facility at various sampling points and sampling times.
生物膜是食品企业中重要的污染源，但实际中生物膜的组成大多仍不为人知。清洁和消毒后采集的表面样本的化学和微生物特征对于区分生物膜中附着细菌和自由生活细菌非常重要。在本研究中，评估了对表面样本进行化学和微生物分析均可能有用的采样方法。在八家比利时食品公司的生产设施中，清洁和消毒后使用两种采样方法对表面进行采样：刮铲植绒拭子法和海绵棒法。对这些样本进行微生物和化学分析，以评估采样方法对定量这些设施中生物膜来源的细胞外聚合物成分和微生物的适用性。刮铲植绒拭子法最适合对样本进行化学分析，因为这些拭子中的材料不会干扰化学成分的测定。对于微生物计数，海绵棒法比刮铲植绒拭子法略有效，但差异不显著。在除一家之外的所有设施中，至少20%的采样表面每100平方厘米有超过10个菌落形成单位（CFU）。在20%的化学分析表面样本中发现了蛋白质，在15%和8%的样本中分别发现了碳水化合物和糖醛酸。当化学和微生物结果相结合时，17%的采样表面同时受到微生物和至少一种分析化学成分的污染；因此，这些表面被认定为带有生物膜。总体而言，食品行业中的微生物污染在不同食品部门之间差异很大，甚至在同一设施内的不同采样点和采样时间也是如此。
