A rapid HPLC method for the extraction and quantification of vitamin B12 in dairy products and cultures of Propionibacterium freudenreichii

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Table II.

Comparison of vitamin B₁₂ results from HPLC and microbiological assays (n = 3). Values are reported as mean ± SD.

Sample (strain and growth medium)	Microbiological assay (μg·mL⁻¹ broth)	HPLC results (μg·mL⁻¹ broth)	P value^c
J10 (YEL)^a	0.25 ± 0.01	0.23 ± 0.01	0.40
J17 (YEL)^a	0.22 ± 0.01	0.22 ± 0.01	0.82
J8 (B12 medium)^b	2.23 ± 0.19	2.25 ± 0.03	0.84
J9 (B12 medium)^b	0.29 ± 0.02	0.32 ± 0.04	0.31
J10 (B12 medium)^b	2.04 ± 0.07	2.12 ± 0.05	0.38
J15 (B12 medium)^b	1.69 ± 0.04	1.77 ± 0.01	0.06
J16 (B12 medium)^b	0.66 ± 0.01	0.77 ± 0.06	0.09
J17 (B12 medium)^b	0.25 ± 0.01	0.27 ± 0.01	0.29
J18 (B12 medium)^b	0.26 ± 0.01	0.33 ± 0.01	0.92
J19 (B12 medium)^b	0.14 ± 0.00	0.16 ± 0.02	0.20

^a,b

YEL and B₁₂ media were sampled at 216 and 73 h, respectively.

The Student’s t test (independent samples) was performed to establish whether the results of the two methods differed significantly. P ≤ 0.05 indicates significance.