Department of Agriculture, Forestry, and Food Sciences, University of Turin, Turin, Italy.
Laemmegroup s.r.l., Moncalieri, Italy.
Appl Environ Microbiol. 2020 Nov 10;86(23). doi: 10.1128/AEM.01861-20.
Microbial complexity and contamination levels in food processing plants heavily impact the final product fate and are mainly controlled by proper environmental cleaning and sanitizing. Among the emerging disinfection technologies, ozonation is considered an effective strategy to improve the ordinary cleaning and sanitizing of slaughterhouses. However, its effects on contamination levels and environmental microbiota still need to be understood. For this purpose, we monitored the changes in microbiota composition in different slaughterhouse environments during the phases of cleaning/sanitizing and ozonation at 40, 20, or 4 ppm. Overall, the meat processing plant microbiota differed significantly between secondary processing rooms and deboning rooms, with a greater presence of psychrotrophic taxa in secondary processing rooms because of their lower temperatures. Cleaning/sanitizing procedures significantly reduced the contamination levels and in parallel increased the number of detectable operational taxonomic units (OTUs), by removing the masking effect of the most abundant human/animal-derived OTUs, which belonged to the phylum Subsequently, ozonation at 40 or 20 ppm effectively decreased the remaining viable bacterial populations. However, we could observe selective ozone-mediated inactivation of psychrotrophic bacteria only in the secondary processing rooms. There, the and abundances and their viable counts were significantly affected by 40 or 20 ppm of ozone, while more ubiquitous genera like showed a remarkable resistance to the same treatments. This study showed the effectiveness of highly concentrated gaseous ozone as an adjunct sanitizing method that can minimize cross-contamination and so extend the meat shelf life. Our survey demonstrates that RNA-based sequencing of 16S rRNA amplicons is a reliable approach to qualitatively probe, at high taxonomic resolution, the changes triggered by new and existing cleaning/sanitizing strategies in the environmental microbiota in human-built environments. This approach could soon represent a fast tool to clearly define which routine sanitizing interventions are more suitable for a specific food processing environment, thus limiting the costs of special cleaning interventions and potential product loss.
食品加工厂中的微生物复杂性和污染水平对最终产品的命运有重大影响，主要通过适当的环境清洁和消毒来控制。在新兴的消毒技术中，臭氧处理被认为是改善屠宰场普通清洁和消毒的有效策略。然而，其对污染水平和环境微生物群的影响仍需进一步了解。为此，我们监测了在清洗/消毒和 40、20 或 4 ppm 臭氧处理阶段不同屠宰场环境中微生物群落组成的变化。总体而言，肉类加工厂的微生物群在二级加工室和去骨室之间存在显著差异，由于二级加工室温度较低，因此存在更多的嗜冷类群。清洗/消毒程序通过去除最丰富的人类/动物来源 OTU 的掩蔽效应，显著降低了污染水平，并平行增加了可检测的操作分类单元 (OTU) 的数量。随后，40 或 20 ppm 的臭氧有效地降低了剩余的活菌数量。然而，我们只能观察到臭氧对嗜冷细菌的选择性灭活，仅在二级加工室中观察到这种情况。在那里，和 的丰度及其活菌数受到 40 或 20 ppm 臭氧的显著影响，而像 这样更为普遍的属则对相同的处理表现出明显的抗性。本研究表明，高浓度气态臭氧作为一种辅助消毒方法是有效的，可以最大限度地减少交叉污染，从而延长肉类的保质期。我们的调查表明，基于 16S rRNA 扩增子的 RNA 测序是一种可靠的方法，可以在高分类分辨率下定性探测新的和现有的清洁/消毒策略对人为环境中环境微生物群所引发的变化。这种方法很快可能成为一种快速工具，明确定义哪些常规消毒干预措施更适合特定的食品加工环境，从而限制特殊清洁干预措施的成本和潜在的产品损失。
