Rode Tone Mari, McLeod Anette, Måge Ingrid, Heir Even, Axelsson Lars, Holck Askild L
Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 8034, 4068 Stavanger, Norway.
Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, 1431 Ås, Norway.
Int J Microbiol. 2017;2017:5176384. doi: 10.1155/2017/5176384. Epub 2017 Oct 29.
The ability of foodborne pathogens to exhibit adaptive responses to stressful conditions in foods may enhance their survival when passing through the gastrointestinal system. We aimed to determine whether surviving stresses encountered during a model dry-fermented sausage (DFS) production process exhibit enhanced tolerance and survival in an gastrointestinal model. Salami sausage batters spiked with five isolates, including enterohaemorrhagic strains isolated from different DFS outbreaks, were fermented in a model DFS process (20°C, 21 days). Control batters spiked with the same strains were stored at 4°C for the same period. Samples from matured model sausages and controls were thereafter exposed to an digestion challenge. Gastric exposure (pH 3) resulted in considerably reduced survival of the strains that had undergone the model DFS process. This reduction continued after entering intestinal challenge (pH 8), but growth resumed after 120 min. When subjected to gastric challenge for 120 min, that had undergone the DFS process showed about 2.3 log lower survival compared with those kept in sausage batter at 4°C. Our results indicated that strains surviving a model DFS process exhibited reduced tolerance to subsequent gastric challenge at low pH.
食源性病原体对食品中应激条件表现出适应性反应的能力，可能会在其通过胃肠道系统时提高它们的存活率。我们旨在确定在模拟干发酵香肠（DFS）生产过程中所经历的应激存活情况，是否会使其在胃肠道模型中表现出更强的耐受性和存活率。用五种菌株（包括从不同DFS疫情中分离出的肠出血性菌株）接种的萨拉米香肠面糊，在模拟DFS过程（20°C，21天）中进行发酵。用相同菌株接种的对照面糊在4°C下储存相同时间。此后，将成熟的模拟香肠和对照的样品进行消化挑战。胃部暴露（pH 3）导致经历模拟DFS过程的菌株存活率大幅降低。进入肠道挑战（pH 8）后，这种降低仍在持续，但120分钟后恢复生长。在接受120分钟的胃部挑战时，经历DFS过程的菌株与在4°C下保存在香肠面糊中的菌株相比，存活率低约2.3个对数。我们的结果表明，在模拟DFS过程中存活的菌株对随后低pH值的胃部挑战耐受性降低。
