Bioluminescence lights the way to food safety

Abstract

The food industry is increasingly adopting food safety and quality management systems that are more proactive and preventive than those used in the past, which have tended to rely on end product testing and visual inspection. The regulatory agencies in many countries are promoting one such management tool, Hazard Analysis Critical Control Point (HACCP), as a way to achieve a safer food supply and as a basis for harmonization of trading standards. Verification that the process is safe must involve microbiological testing but the results are not, as yet, generated in real-time. Of all the rapid microbiological tests currently available, the only ones that come close to offering real-time results are bioluminescence-based methods. Recent developments in the application of bioluminescence for food safety issues are presented in this paper. These include the use of genetically engineered microorganisms with bioluminescent and fluorescent phenotypes as a real time indicator of physiological status of bacterial cells and survival of food-borne pathogens in food and food processing environments as well as novel bioluminescent-based methods for rapid detection of pathogens in food and environmental samples. Advantages and pitfalls of the methods are discussed.

Monitoring Bioluminescent Pseudomonas aeruginosa on Mechano-Bactericidal Zinc Oxide Nanopillars: Implications for Self-Cleaning Antibacterial Coatings

“…For instance, when incubated in LB media over 24 h, bioluminescent P. aeruginosa exhibited growth (Figure A) comparable to that of wild-type P. aeruginosa , as quantified by the absorbance measured at OD 600 , a standard cell enumeration technique. However, bioluminescence signal of P. aeruginosa prepared in the same way was maximal only when the cells were the most metabolically active at the early-to-midexponential phase of growth (Figure B), consistent with bioluminescent strains characterized in the literature . By extension, the time point at which the peak bioluminescence signal was detected was dependent on the initial number of viable bacteria in the inoculum.…”

“…However, bioluminescence signal of P. aeruginosa prepared in the same way was maximal only when the cells were the most metabolically active at the early-to-midexponential phase of growth (Figure 1B), consistent with bioluminescent strains characterized in the literature. 25 By extension, the time point at which the peak bioluminescence signal was detected was dependent on the initial number of viable bacteria in the inoculum. A culture with a higher inoculum reached the peak bioluminescence signal more rapidly than that with a low inoculum (Figure S2).…”

“…Monitoring bacterial bioluminescence is an established technique to quantify bacterial survival and recovery that first gained widespread acceptance in environmental microbiology and food microbiology, and more recently in medical microbiology, due to several advantages. − In addition to the noninvasive nature of monitoring bioluminescence, real-time production of bioluminescence is strongly dependent on the metabolic activity of bacterial cells, making bioluminescence an excellent indicator to measure both acute inactivation within minutes of exposure and potential recovery after many hours of incubation in nutrient-rich conditions . There are several ways to quantify bacterial bioluminescence.…”

“…19−25 In addition to the noninvasive nature of monitoring bioluminescence, realtime production of bioluminescence is strongly dependent on the metabolic activity of bacterial cells, making bioluminescence an excellent indicator to measure both acute inactivation within minutes of exposure and potential recovery after many hours of incubation in nutrient-rich conditions. 25 There are several ways to quantify bacterial bioluminescence. Perhaps the most straightforward approach is via a microplate reader equipped with a luminescence detector.…”