Niboucha Nissa, Goetz Coralie, Sanschagrin Laurie, Fontenille Juliette, Fliss Ismaïl, Labrie Steve, Jean Julie
Département des Sciences des Aliments, Université Laval, Québec, QC, Canada.
Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, QC, Canada.
Front Microbiol. 2022 Jun 13;13:892181. doi: 10.3389/fmicb.2022.892181. eCollection 2022.
The formation of biofilms in dairy processing plants can reduce equipment efficiency, contribute to surface deterioration, and contaminate dairy products by releasing the microorganisms they contain, which may cause spoilage or disease. However, a more representative identification of microbial communities and physico-chemical characterization requires to detach and recover adequately the entire biofilm from the surface. The aim of this study is to develop an efficient technique for in-plant biofilm sampling by growing a strain of PFl1A on stainless-steel surface in a dynamic CDC biofilm reactor system using tryptic soy broth (TSB) and milk as growth media. Different techniques, namely, swabbing, scraping, sonic brushing, synthetic sponge, and sonicating synthetic sponge were used and the results were compared to a standard ASTM International method using ultrasonication. Their efficiencies were evaluated by cells enumeration and scanning electron microscopy. The maximum total viable counts of 8.65 ± 0.06, 8.75 ± 0.08, and 8.71 ± 0.09 log CFU/cm were obtained in TSB medium using scraping, synthetic sponge, and sonicating synthetic sponge, respectively, which showed no statistically significant differences with the standard method, ultrasonication (8.74 ± 0.02 log CFU/cm). However, a significantly ( < 0.05) lower cell recovery of 8.57 ± 0.10 and 8.60 ± 0.00 log CFU/cm compared to ultrasonication were achieved for swabbing and sonic brushing, respectively. Furthermore, scanning electron microscopy showed an effective removal of biofilms by sonic brushing, synthetic sponge, and sonicating synthetic sponge; However, only the latter two methods guaranteed a superior release of bacterial biofilm into suspension. Nevertheless, a combination of sonication and synthetic sponge ensured dislodging of sessile cells from surface crevices. The results suggest that a sonicating synthetic sponge could be a promising method for biofilm recovery in processing plants, which can be practically used in the dairy industries as an alternative to ultrasonication.
乳制品加工厂中生物膜的形成会降低设备效率，导致表面损坏，并通过释放其中所含的微生物污染乳制品，这些微生物可能会导致产品变质或引发疾病。然而，要更具代表性地鉴定微生物群落并进行物理化学表征，需要从表面充分分离并回收整个生物膜。本研究的目的是通过在动态疾控中心生物膜反应器系统中的不锈钢表面上，使用胰蛋白胨大豆肉汤（TSB）和牛奶作为生长培养基培养PFl1A菌株，开发一种用于工厂内生物膜采样的高效技术。使用了不同的技术，即擦拭、刮擦、声波刷、合成海绵和超声合成海绵，并将结果与使用超声处理的标准ASTM国际方法进行比较。通过细胞计数和扫描电子显微镜评估它们的效率。在TSB培养基中，分别使用刮擦、合成海绵和超声合成海绵获得的最大总活菌数为8.65±0.06、8.75±0.08和8.71±0.09 log CFU/cm，与标准方法超声处理（8.74±0.02 log CFU/cm）相比，无统计学显著差异。然而，擦拭和声波刷分别实现的细胞回收率明显（<0.05）低于超声处理，分别为8.57±0.10和8.60±0.00 log CFU/cm。此外，扫描电子显微镜显示声波刷、合成海绵和超声合成海绵能有效去除生物膜；然而，只有后两种方法能保证细菌生物膜更好地释放到悬浮液中。尽管如此，超声处理和合成海绵的组合可确保从表面缝隙中去除固着细胞。结果表明，超声合成海绵可能是加工厂生物膜回收的一种有前景的方法，可在乳制品行业实际用作超声处理的替代方法。
