`Glowing bacteria` help meat treatment project

A project to develop effective techniques for the ‘surface pasteurisation’ of food led by the University of Bristol is being helped by a new technique developed by scientists at the University of the West of England. Officially titled ‘BUGDEATH’ the project, which in total has eight partners, is aimed at ‘Predicting microbial death during heat treatments on foods’.

Researchers based at the University of Bristol Food Refrigeration and Process Engineering Centre, have been looking at ‘steam pasteurisation’ for some time – a process whereby steam is blown at the surface of the food (for example meat) at a high temperature for a short time to kill any bacteria before it is stored or processed.

The BUGDEATH project will focus on what happens to the bacteria which are treated in this way and with other ‘dry’ treatments. It will assess how the speed of the surface temperature change affects the bacteria. The project will look at how the bacteria die and how long this takes. The researchers will use real food rather than just samples in test tubes so that the data they produce has real relevance for the food industry.

Testing the effectiveness of the various techniques using traditional methods can take up to 24 hours to produce results. Now scientists at UWE have come up with a more efficient method of measuring the effectiveness of the steaming and other techniques.

Using organisms which have been treated by adding lux genes to make them glow (bioluminescence), and applying them to the food surface to be treated, the scientists can quickly measure changes taking place in the bacteria. If the bioluminescence fades when the food is treated then the process is effective. The bacteria glow brightly when healthy, fade when expiring and stop glowing the moment they die.

The data gained from these tests will be used to produce mathematical models, enabling a wide range of food manufacturers to design more effective and efficient treatments for foods.

Dr Vyv Salisbury, a senior microbiologist from UWE who is working on the project, says, “Finding ways to make our food safer is important for food manufacturers and consumers as well as for scientists. The use of the LUX genes in this project provides a useful comparison with traditional testing methods and can give rapid results to the researchers.”

Lux genes have been used for several years by scientists and researchers. They are the genes which give creatures such as fireflies, glow worms and marine bacteria the ability to ‘light up’.

Scientists at UWE have also used the lux genes in research to test the effectiveness of antibiotics.

The current project, which is EEC funded, is coordinated by the University of Bristol with 7 partners including UWE.