A rapid and sensitive method based on measurement of carbon dioxide released from a culture medium as a result of bacterial metabolism of glucose is reported. The rate of release of carbon dioxide was measured by recording the absorbance at 2353 cm−1 (4.25 μm) against time using a standard infrared spectrophotometer. Detection of growth from only five organisms of Salmonella typhosa was significant after just fifteen minutes. In about three hours a clear pattern of growth was obtained by this method. The results are reproducible with a standard deviation around ±0.5%.
