Department of Microbial and Molecular Systems (MS), Lab4Food, KU Leuven, Geel Campus, Geel, Belgium.
Department of Microbial and Molecular Systems (MS), Laboratory for Process Microbial Ecology and Bioinspirational Management (PME & BIM), KU Leuven, De Nayer Campus, Sint-Katelijne-Waver, Belgium.
Appl Environ Microbiol. 2018 May 31;84(12). doi: 10.1128/AEM.00255-18. Print 2018 Jun 15.
In this study, the microbiota during industrial rearing, processing, and storage of the edible tropical house cricket, , was investigated. To this end, we analyzed samples from the cricket feed, obtained before feeding as well as from the cages, and from the crickets during rearing, after harvest, and after processing into frozen, oven-dried, and smoked and oven-dried (smoked/dried) end products. Although the feed contained lower microbial numbers than the crickets, both were dominated by the same species-level operational taxonomic units, as determined by Illumina MiSeq sequencing. They corresponded, among others, to members of , , , and The harvested crickets contained high microbial numbers, but none of the investigated food pathogens spp., , , or coagulase-positive staphylococci. However, some possible mycotoxin-producing fungi were isolated from the crickets. A postharvest heat treatment, shortly boiling the crickets, reduced microbial numbers, but an endospore load of 2.4 log CFU/g remained. After processing, an increase in microbial counts was observed for the dried and smoked/dried crickets. Additionally, in the smoked/dried crickets, a high abundance of a sp. was observed. Considering the possible occurrence of food-pathogenic species from this genus, it is advised to apply a heat treatment which is sufficient to eliminate spores. Nevertheless, the microbial numbers remained constant over a 6-month storage period, whether frozen (frozen end product) or at ambient temperature (oven-dried and smoked/dried end products). The need for sustainable protein sources has led to the emergence of a new food sector, producing and processing edible insects into foods. However, insight into the microbial quality of this new food and into the microbial dynamics during rearing, processing, and storage of edible insects is still limited. Samples monitored for their microbiota were obtained in this study from an industrial rearing and processing cycle. The results lead first to the identification of process steps which are critical for microbial food safety. Second, they can be used in the construction of a Hazard Analysis and Critical Control Points (HACCP) plan and of a Novel Food dossier, which is required in Europe for edible insects. Finally, they confirm the shelf-life period which was determined by the rearer.
在这项研究中，我们调查了食用热带家蟋蟀在工业养殖、加工和储存过程中的微生物群。为此，我们分析了蟋蟀饲料的样本，这些样本是在喂食前从笼子里以及在养殖过程中、收获后、加工成冷冻、烤箱干燥、烟熏和烤箱干燥（烟熏/干燥）的终产品中获得的。尽管饲料中的微生物数量低于蟋蟀，但通过 Illumina MiSeq 测序确定，它们都以相同的种水平操作分类单位为主。其中包括 、 、 和 的成员。收获的蟋蟀含有大量的微生物，但未发现调查的任何食源性病原体，如 spp.、 、 或凝固酶阳性葡萄球菌。然而，从蟋蟀中分离出了一些可能产生霉菌毒素的真菌。收获后的热处理，即短时间煮沸蟋蟀，可以减少微生物数量，但仍残留 2.4 对数 CFU/g 的孢子。加工后，干燥和烟熏/干燥的蟋蟀的微生物数量增加。此外，在烟熏/干燥的蟋蟀中，观察到一种 sp.的高丰度。考虑到该属可能存在食源性病原体，建议采用足以消除孢子的热处理。然而，无论是冷冻（冷冻终产品）还是在环境温度下（烤箱干燥和烟熏/干燥终产品），在 6 个月的储存期内，微生物数量保持不变。对可持续蛋白质来源的需求催生了一个新的食品行业，将食用昆虫加工成食品。然而，对这种新食品的微生物质量以及食用昆虫在养殖、加工和储存过程中的微生物动态的了解仍然有限。本研究中监测微生物群的样本是从工业养殖和加工周期中获得的。结果首先确定了对微生物食品安全至关重要的工艺步骤。其次，它们可用于构建危害分析和关键控制点（HACCP）计划和新型食品文件，欧洲对食用昆虫有此要求。最后，它们证实了养殖者确定的保质期。
