Greenacre E J, Brocklehurst T F
Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, UK.
Int J Food Microbiol. 2006 Oct 15;112(1):62-5. doi: 10.1016/j.ijfoodmicro.2006.05.012. Epub 2006 Jul 13.
Salmonella typhimurium induces an Acid Tolerance Response (ATR) upon exposure to mildly acidic conditions in order to protect itself against severe acid shock. This response can also induce cross-protection to other stresses such as heat and salt. We investigated whether both the acetic acid induced and lactic acid induced ATR in S. typhimurium provided cross-protection to a salt stress at 20 degrees C. Acid-adapted cells were challenged with both a sodium chloride (NaCl) and potassium chloride (KCl) shock and their ability to survive ascertained. Acetic acid adaptation provided cells with protection against both NaCl and KCl stress. However, lactic acid adaptation did not protect against either osmotic stressor and rendered cells hypersensitive to NaCl. These results have implications for the food industry where hurdle technology means multiple sub-lethal stresses such as mild pH and low salt are commonly used in the preservation of products.
鼠伤寒沙门氏菌在暴露于轻度酸性条件下时会诱导产生酸耐受反应（ATR），以保护自身免受严重的酸冲击。这种反应还可以诱导对其他应激（如热和盐）的交叉保护。我们研究了鼠伤寒沙门氏菌中由乙酸诱导和乳酸诱导的ATR是否都能在20摄氏度时对盐胁迫提供交叉保护。用氯化钠（NaCl）和氯化钾（KCl）冲击对酸适应细胞进行挑战，并确定它们的存活能力。乙酸适应为细胞提供了对NaCl和KCl胁迫的保护。然而，乳酸适应并不能抵御任何一种渗透胁迫源，反而使细胞对NaCl高度敏感。这些结果对食品工业具有重要意义，在食品工业中，栅栏技术意味着在产品保存中通常会使用多种亚致死应激，如轻度pH值和低盐。
