title: The performance of tofu-whey as a liquid medium in the propagation of mycobacterium tuberculosis strain H37Rv.
abstract: OBJECTIVE
  To investigate the performance of "tofu-whey liquid medium" for the propagation of Mycobacterium tuberculosis (MTB) strain H37Rv.
  
  
  METHODS
  Two hundred micro liters (200μl) of 1 McFarland standard (1mg/ml-bacillary suspension) were inoculated into different batches of tofu-whey liquid medium. Each series contained three trials of test (tofu-whey liquid medium) and control media (Middlebrook 7H9 medium). Turbidity was measured within three weeks of inoculation using a nephelometer. The combinations of various tofu-whey liquid culture media were as follows; T1 (tofu-whey+ADC+glycerol+Potassium sulfate+Magnesium citrate+Sodium glutamate); T2 (tofu-whey+ADC+glycerol+Potassium sulfate+Magnesium citrate); T3 (tofu-whey+ADC+glycerol+Potassium sulfate); T4 (tofu-whey+ADC+glycerol); T5 (tofu-whey+ADC); and T6 (tofu-whey only).
  
  
  RESULTS
  In all test and control liquid culture media, the multiplication of M. tuberculosis was documented under light and fluorescence microscopy. Of various tofu-whey medium used, T1 demonstrated the most potential for MTB propagation. The increased turbidity reading represented by the value in "unit drop of % transmittance" was higher (25 scores) in the T1 tofu-whey medium, compared with the T6 tofu-whey medium (8 scores). The overall growth was significantly better in Middlebrook 7H9 culture media, although by the third day of incubation, the bacillary growth was superior in the T1 tofu-whey culture media. Sub-cultures in Lowenstein-Jensen (L-J) medium yielded between 87% (47 of 54) and 89% (48 of 54) recovery rate with between 7% and 13% contamination rate with coagulase-negative staphylococci.
  
  
  CONCLUSIONS
  Tofu-whey media can be used as an economical alternative to Middlebrook 7H9 in resource-limited settings.
authors.affiliation: National Tuberculosis Reference Laboratory, Research Institute of Tropical Medical Medicine, FICC, Alabang, Muntinlupa City, Metro Manila 1770, Philippines; College of Medical Technology, Philippine Women's University, Taft ave., Manila 1004, Philippines; Department of Medical Technology, Institute of Arts and Sciences, Far Eastern University, Nicanor Reyes Sr. Street, Sampaloc, Manila 1015, Philippines. Electronic address: frederick_masangkay2002@yahoo.com.
authors.forename: Frederick R
authors.initials: FR
authors.lastname: Masangkay
keywords: Liquid culture medium; Mycobacterium tuberculosis; Tofu-whey