Traditional plate count method used to assess Lactobacillus stress resistance by determining the number of viable bacteria to calculate the survival rate has the problems of long detection cycle and large errors caused by human operation. To mitigate these drawbacks, the feasibility of determining the viability of Lactobacillus by the turbidimetric assay using spectrophotometer was evaluated. Experiments showed that the biomass ratio (biomass of the stress group to biomass of the control group) at sampling times had a significant linear correlation with the viability of L. fermentum 415 (ranged from 0.06-0.85) under acidic stress (R2 = 0.997 1). This standard equation of acidic stress could also be used to determine the viability under different types of stress (e.g., H2O2 stress, bile-salt stress, and cold stress) with error rates below 10%. It was confirmed that this method could also be used to evaluate the viabilities of another Lactobacillus strain, L. plantarum LGD, after exposure to various stresses. This light scattering assay required less detection time than that of plate culture, and the measurement result had a good linear correlation with the result obtained by the plate count method. Also, this method reduced the errors caused by dilution, therefore, facilitating rapid and accurate detection of viability of Lactobacillus under multiple stress.
XU Qian
,
FU Ruiyan
. Viability determination of Lactobacillus under stress by the turbidimetric assay using spectrophotometer[J]. Food and Fermentation Industries, 2021
, 47(12)
: 257
-261
.
DOI: 10.13995/j.cnki.11-1802/ts.026591
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