Salmonella in the sights for genomic research

Salmonella in the sights for genomic research

By Joe Whitworth+, 10Aug2015,

Two Canadian universities have been given almost $10m for research to reduce Salmonella on fresh produce. Researchers from McGill and Laval universities received funding from Genome Canada and Génome Québec.

Dr Lawrence Goodridge of McGill University and Roger C. Levesque from the Institute for Integrative Systems Biology (IBIS), Université Laval, are leading the work which will use whole genome sequencing (WGS) to identify the specific Salmonella strains that cause human disease. The team will then develop tests to detect Salmonella on fresh produce and improve the response when there is a foodborne outbreak to limit illnesses.

Project parts
Dr Goodridge, director, Food Safety and Quality Program in the Department of Food Science and Agricultural Chemistry, said the research will start from October and last four years.

“There are two parts, sequencing the whole genomes of 4,500 isolates of Salmonella and we hope to complete that within one year or 18 months. We will then use that data in the second half of the project to develop better ways to control Salmonella on food pre and post harvest,” he told FoodQualiyNews.

“We want to improve rapid diagnostics and improve response when foodborne outbreaks occur as methods now are not robust enough, if you can’t figure out the source people are still getting sick. You need to remove foods faster from grocery store shelves and decrease outbreak cases.”

Most outbreaks come from fruit and vegetables, which become infected from the soil they grow in when that soil is polluted by animal waste or nonpotable water.

Each year, Salmonella infects some 88,000 people in Canada who eat contaminated food.

Salmonella infection is thought to cost the Canadian economy as much as $1bn each year in medical costs, absences from work and economic losses to food companies and restaurants.

WGS, PCR and bacteriophages

Dr Goodridge said the focus of the research came from work he and colleagues had done.

“We want to know what is certain for Salmonella to become illness –causing from those strains that don’t [cause illness],” he said.

“Salmonella is the leading cause of foodborne illness worldwide and fresh produce is one of the leading causes in Canada and the US, so we hope to look at isolates from a variety of sources.

“WGS is fastbecoming the goto technology as it is the method that gives you the most information about the bacteria. It generates the information on Salmonella and when we have that we can refine where to look.

“This will be the first thing but then we will use other technologies to improve the rapid diagnostics which are PCR-based so once we have the sequences we can determine the focus with PCR assays and improve immunoassays.”

It is one of 11 projects which were awarded grants by Genome Canada with the Western Grains Research Foundation (WGRF), last month.

They represent an investment of $93m: $30.8m of federal funding through Genome Canada; $5m from WGRF towards three of the projects; and the balance from project cofunders.

Researchers will develop natural biosolutions to control the presence of Salmonella in fruit and vegetables as they are growing in the field.

Dr Goodridge said once contamination happens on produce it is hard to get rid of as there is no kill step, unlike cooking for meat, which is where the development of natural biosolutions to control Salmonella in fruit and vegetables as they are growing in the field comes in.

“Chlorine removes some cells but not all and with Salmonella some cells is all you need to cause illness. We will look at natural alternatives as the consumer movement is not to want pesticides.”

“We will focus on bacteriophages which can infect a cell and kill it. They are in the air and on the skin and are harmless.”