胁迫因素对玻璃表面蜡样芽孢杆菌菌膜形成的影响分析

Effects of stress factors on the formation of Bacillus cereus biofilm on glass surfaces

以食源性致病菌蜡样芽孢杆菌形成的菌膜为研究对象,模拟食品加工过程中温度胁迫、酸碱胁迫、营养胁迫、渗透胁迫、防腐剂胁迫等外源条件,采用超声波平板菌落计数玻璃表面菌膜形成量,结晶紫染色法观察菌膜在玻璃表面的生长形态。结果表明:温度胁迫下,低温4℃、高温50℃均能形成菌膜且随着温度升高菌膜形成量先升高后降低,温度30℃时菌膜形成量最大;酸碱胁迫下,p H小于或大于7.0时,菌膜的形成受到抑制,p H7.0时菌膜形成量最大;营养胁迫下,添加葡萄糖有利于菌膜形成,添加4%葡萄糖有明显的促进菌膜形成的效果;渗透胁迫下,低浓度的氯化钠对蜡样芽孢杆菌菌膜形成有促进作用,高浓度的氯化钠对菌膜形成有抑制作用,添加0.5%氯化钠有明显的促进菌膜形成的效果;防腐胁迫下,食品防腐剂浓度为0.15%高于浓度为0.10%时的菌膜形成量,在食品加工中不能仅凭加入食品防腐剂而疏忽对菌膜的控制。

Biofilms formed by foodborne pathogenic bacteria Bacillus cereus was used as material, the effect of food processing temperature stress, pH stress, nutritional stress, osmotic stress and preservatives stress on the formation of Bacillus cereus biofilms were investigated, and the formation of the biofilms were measured by ultrasonic plate method and observed crystal violet staining.The results showed that under the temperature stress, the Bacillus cereus biofilm formed at 4 ℃ and 50 ℃, the formation of biofilms were increased then decreased with increasing temperature, Bacillus cereus formed stable biofilms at 30 ~C. Under the pH stress, when the pH was less or more than 7.0, the formation of biofims were significantly reduced, Bacillus cereus formed stable biofilms at pH7.0. Under the stress of nutrition, the abilities of biofilms formation would be improved by adding proper glucose in culture medium and the 4% glucose had obvious effect on promoting the formation of Bacillus cereus biofilms.Under the osmotic stress,low concentration of sodium chloride promoted the formation of Bacillus cereus biofilms,high concentration of sodium chloride could inhibit the formation of Bacillus cereus biofilms and the 0.5% sodium chloride had obvious effect on promoting the formation of Bacillus cereus biofilms.Under preservative stress, the Bacillus cereus biofims of adding 0.15% food preservative were higher than 0.10%. In the food processing, it would not neglect controling bacteria biofilms just only adding food preservatives.