August 2006
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2,874 Reads
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142 Citations
Lactobacillus acidophilus was suspended in broth and buffer at pH 2, 3 and 4 and incubated at 37°C for 2 hr. In both broth and buffer pH 2, viable cell numbers decreased rapidly, and none were recovered after 45 min. At pH 4 in broth and buffer, the number of cells was not significantly reduced in 2 hr. In potassium phthalate buffer at p 3, no viable cells were recovered after 30 min, while in KCl buff and broth at pH 3, no significant reduction was seen. Cells subjected to low pH for up to 5 h were able to adhere to human intestinal cells in vitro. Exposure to low pH did not appear to disrupt the ruthenium red staining layer exterior to the cell wall.