Culture media enumeration

A Brain glycolipids (gl), (500 ng, and glycoprotein (gp), 100 ng, were added to AKR spleen cells, and resulting PFC were enumerated in a lawn of C3H thymocytes. Culture medium (m) was added to control cultures. Antigens are identified by Thy-1.2 (C3H) or Thy-I.I (AKR) according to the mice from which they were derived. Control cultures were absorbed before addition to cultures with anti-Thy-1.2 (a-1.2) or anti-Thy-1.1 (a-I.l) antisera. Values are the means and standard errors of five cultures (3). 

In samples with hydrophobic compounds, enumeration of SRB and general anaerobic bacteria (GAnB) may be compromised because of the low solubilization of these compounds in the culture medium. The study of the influence of surfactants in the SRB and GAnB estimation in oil samples may become an alternative to improve the MPN method under these conditions. Surfactants are organic compounds that present both a hydrophobic part and a hydrophilic part in the same molecule. This hydrophilic part allows surlaclants to be soluble in water, whereas the hydrophobic part causes them to concentrate at interfaces [4]. 

The analytical methods used by the industry to evaluate yeasts present in drinks are still, generally, laborious and provide poor information. The most common microbial indicator is still the yeasts and molds , resulting from the utilization of a rich culture medium (supplemented with antibiotics to prevent bacterial growth) to enumerate yeasts and molds. However, this indicator does not distinguish between the dangerous spoilage yeasts and others. 

International Standard, ISO 6222 (1988). Water Quality—Enumeration of viable microorganisms—Colony count by inoculation in or on a nutrient agar culture medium. International Organization for Standardization, Geneva, Switzerland. 

Pour plates A pour plate is one in which the liquid sample to be micro-biologically enumerated is aseptically transferred into a Petri dish, and cooled (yet liquid) agar medium is added to the culture. The medium and the liquid sample must be well mixed prior to solidification of tfie agar gel. 

---