Adenosine Triphosphate Content of Microorganisms Related with Food Spoilage

Abstract

The luciferin-luciferase bioluminescence method was used to estimate the amount of adenosine triphosphate (ATP) in microorganisms including 15 species of Gram-negative bacteria, 7 of Gram-positive bacteria, and one yeast. A LUMAC Biocounter M2500 was used. The correlation between relative light units (RLU) and ATP in saline solution and nutrient broth was 1.00. The amount of ATP (pico-gram) in all tested strains was calculated by using the standard curve of the saline solution for the serial dilutions of the cultures in nutrient broth. After 24hr cultures, a linear relationship was obtained between amount of ATP and number of viable propagules of Escherichia coli ATCC 11775. The lowest detection level for E. coli cells was 3.5×10³ CFU/ml. The average amount of ATP in Gram-negative bacteria, Gram-positive bacteria, and yeast (Candida albicans) was 1.43, 12.48, and 212.81 fg/cell, respectively, the ATP level in C. albicans being about hundred times higher than the amount in most Gram-negative bacteria. The amount of ATP in Gram-positive bacteria, both rods and cocci, was ten times higher than that in Gram-negative bacteria. However, the amount of ATP in the spore of Bacillus species was very low. The findings suggest that the bioluminescenceis a rapid and useful method for estimating the number of micoorganisms, but the flora of the samples must be identified before using the bioluminescence method.