Submitted to: Luminescence
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2004
Publication Date: 5/17/2005
Citation: Tu, S., Gehring, A.G., Irwin, P.L. 2005. Bioenergetic confirmation of viable pathogens in foods by atp-bioluminescence. Luminescence. p. 445-448.
Interpretive Summary: Contamination of pathogenic bacteria, e.g., E coli O157:H7 and Salmonella in foods may lead to serious public health concerns. To minimize a possible outbreak of food poisoning by these bacteria, sensitive and rapid detection techniques are needed. Current available methods for detecting viable pathogenic bacteria are time consuming and have low sensitivity. In this work, we developed a new process to detect viable bacteria. The method involved the applications of chemical-induced physiological responses of live bacteria and a very sensitive bioluminescence detection process. Since the responses are related to cellular metabolic functions, the developed process may be used to ascertain the presence of viable bacteria. The method was shown to be able to detect 1 viable cell of E. coli O157:H7 spiked in 1 gram of ground beef. The information is useful for researchers and/or engineers to design a process to detect viable and specific pathogens in foods.
Technical Abstract: We have developed a new approach to ascertain the presence of viable bacteria. The bioenergetic status of bacteria was adjusted by the addition of glucose, a carbon energy source, and carbonyl cyanide meta-chlorophenyl hydrazone (CCCP), a membrane protonophore. The addition of glucose restored both the oxygen consumption and the ATP content of the bacteria during cold storage. On the other hand, CCCP enhanced the oxygen consumption and medium acidification but significantly decreased the ATP content. None of the glucose and CCCP effects could be detected with heat-killed bacteria. To develop this pathogen-specific method, Escherichia coli O157 specific immunomagnetic beads were applied to capture the bacteria prior to ATP measurement via luciferin-luciferase induced luminescence. Thus, immunomagnetic capture of the E. coli followed by testing the bioenergetic responses of captured bacteria could ascertain the presence of viable E. coli O157:H7. This CCCP effect allowed the detection of less than one CFU of the E. coli per g of ground beef after a 6-hour enrichment in EC broth at 37°C.