Bacteria viable

The agar [9002-18-0] plate method consists of adding a known quantity of sample, usually 1.0 or 0.1 mL, depending on the concentration of bacteria, to a sterile petti plate and then mixing the sample with a sterile nutrient medium. After the agar medium solidifies, the petti plate is incubated at 32°C for 48 hours after which the bacterial colonies are counted and the number expressed ia terms of a 1 mL or 1 g sample. This procedure measures the number of viable organisms present and able to grow under test conditions, ie, 32°C. 

Eor fresh poultry, a potassium sorbate dip significantly reduces total viable bacteria and doubles the refrigerated shelf life of ice-packed broilers (133). In cooked, uncured, vacuum-packaged turkey and poultry stored at 4°C, 0.2—0.25 wt % potassium sorbate suppresses microbial growth for up to 10 days (134). Sorbic acid at 0.5% in a marinade mixture for chicken dmmmettes extends refrigerator shelf life (135). Country-cured hams sprayed with a 10 wt % potassium sorbate solution showed no mold growth for up to 30 days (136). A review of sorbate use in meat and fish products has been pubHshed (137). 

Waters While MIC-causing bacteria may arrive at the surface of their corrosion worksite by almost any transportation system, there is always water present to allow them to become ac tive and cause MIC to occur. There are plenty of examples of even superpure waters having sufficient microorganisms present to feed, divide, and multiply when even the smallest trace of a viable food-stuff is present (e.g., the so-called watei for injection in the pharmaceutical industiy has been the observed subject of extensive corrosion of pohshed stainless steel tanks, piping, and so on). 

High concentrations or high mass of viable bacteria can be maintained in a relatively small volume. 

CFXI Viable micro-organisms (bacteria, yeasts mould) capable of growth under the prescribed conditions (medium, atmosphere, time and temperature) develop into visible colonies (colony forming units) which are counted. The term colony forming unit (CPU) is used because a colony may result from a single micro-organism or from a clump / cluster of micro-organisms. 

When a sample of living bacteria is inoculated into a medium adequate for growth, the change in viable population with time follows a characteristic pattern (Fig. 1.12). 

It had been found that if bacteria are stained with acridine orange and examined under fluorescent microscopy, viable, as dishnct from dead, cells fluoresce with an orange-led hue. This basic observation has been adapted to an ingenious method of determining bacterial content and may be completed within 1 hour. 

It is doubtful if there is a difference other than degree between bacteriostatic and bactericidal action. The three situations, growth, bacteriostasis and killing, are represented graphically in Fig. 11.1. The question posed by this notion, to which often there is no precise answer, is How long will a culture of bacteria remain viable when prevented from reproducing ... 

Changes in the population of viable bacteria in an environment are determined by means of a viable count, and aplot of this count against time gives a dynamic picture of any pattern of change (see Fig. 11.1, curve A). The typical growth curve of a bacterial culture is constructed from data obtained in this w. The pattern of bacterial death in a lethal environment m be obtained by the same technique, when a death or mortality curve is obtained (Fig. 11.1, curve C). 

BCG Cultures of live BCG cells in liquid or on solid media 1 Bacteria centrifuged from medium 2 Resuspension in stabilizer 3 Freeze-drying Viable count induction of sensitivity to tuberculin in guinea-pigs Exclusion of virulent mycobacteria absence of excessive dermal reactivity... 

The homogeneity determination of the bacteria in the materials is performed by viable count followed by statistical evaluation of the cormts of sub-samples from the same capsule solution and of total counts of different capsules of one batch. An example for the homogeneity determination for a batch of capsules containing Enterococcus faecium is also presented in (Janning et al. 1995). 

Bacteremia (fungemia) Presence of viable bacteria or fungi in the bloodstream. 

In a parallel test with water instead of disinfectant the colony forming units (cfu) of surviving bacteria are determined and the reduction in viable counts is calculated. 

Total viable count per gram Bacteria <10 Fungi <10... 

---