As a deadly listeriosis outbreak causes nationwide concern, food safety experts at Colorado State University are launching a research project to better understand – and prevent – the spread of Listeria monocytogenes bacterium in cantaloupe.
CSU scientists said an outbreak report released by the U.S. Food and Drug Administration underscores the need to examine how Listeria can survive and multiply in environments where cantaloupe are grown, processed, stored and eaten.
“This outbreak in cantaloupe  is a warning. We need to learn a lot more about how the Listeria bacterium behaves throughout the food system in order to protect growers and consumers,” said Lawrence Goodridge, food microbiologist and associate professor in CSU’s College of Agricultural Sciences. “We’re concerned about both farmers and consumers, and our research plan will reflect that.”
The interdisciplinary team of researchers plans to investigate the route of Listeria from farm to fork. They aim to identify potential problem points and solutions to protect the cantaloupe industry and consumers from future outbreaks of contamination and illness.
The research team includes experts in farming practices, foodborne pathogens and consumer food-handling practices.
“This outbreak of listeriosis is worrisome to all of us,” said Craig Beyrouty, dean of the College of Agricultural Sciences. “It’s very appropriate that our researchers are investigating the issue because food safety is an area of internationally recognized expertise at CSU, the outbreak began in our state, and we are committed to helping both consumers and Colorado’s renowned cantaloupe industry.”
Investigation farm to fork
The group will address questions about the movement of Listeria through irrigation water and soil; on-farm washing and packing; farm equipment; and consumer handling, including melon washing, drying, cutting and storage. Among the critical factors examined will be livestock grazing practices, temperature issues and sanitation, as well as the interplay of such factors.
“We want to develop new knowledge that will allow us to update best practices for both growers and consumers,” said Marisa Bunning, food safety Extension specialist and assistant professor in CSU’s College of Applied Human Sciences. “On the consumer side, this is especially important for elderly people, who tend to enjoy cantaloupe because it’s nutritious and easy to eat.”
Public health officials traced the listeriosis outbreak to whole cantaloupe processed at a facility in Holly, Colo. , in the Arkansas River Valley east of the Rocky Ford growing area. In mid-September, melon from that source was recalled, sending shock waves through Colorado’s thriving cantaloupe sector.
The FDA report cited multiple problems at the single facility where tainted cantaloupes were processed. That points to the need for more science-based knowledge to help inform and protect all cantaloupe growers from the “perfect storm” of a contamination event, Goodridge said.
The Colorado cantaloupe industry tallied sales of nearly $8 million in 2010, according to the state office of the National Agricultural Statistics Service. More than 70 percent of Colorado acreage planted in cantaloupes is in the Rocky Ford region, an indication of the cantaloupe industry’s critical role in the Arkansas River Valley farm belt.
“Cantaloupe is an iconic part of the culture in the Arkansas River Valley. It’s much deeper than the economic impact. Rocky Ford’s identity, in particular, revolves around farming this commodity,” said Mike Bartolo, crops specialist and manager of CSU’s Arkansas Valley Research Center. “Farmers are very worried and want to fully understand this outbreak. They are committed to providing a safe and healthy product.”
The CSU research project, funded with seed money from the Colorado Agricultural Experiment Station, comes as deaths and illnesses continue to mount from the listeriosis outbreak.
Listeria monocytogenes, which is widely distributed in the environment, causes listeriosis, a potentially fatal disease that is particularly threatening to infants, pregnant women, the elderly and people with compromised immune systems. Symptoms of listeriosis may develop up to 70 days after consumption of tainted food.
The current multistate outbreak marks the first time listeriosis has been linked to cantaloupe. Listeria contamination previously has been tied to refrigerated, ready-to-eat foods, including unpasteurized dairy products, deli meat and hot dogs.
Pat Kendall, food safety expert and associate dean for research in College of Applied Human Sciences, noted that CSU’s Listeria research will provide a model to help scientists better understand the activity of other foodborne pathogens.
“Our food system has grown increasingly complex, so we must continue to understand, adapt and improve the safety of our food from our farms to our homes,” Kendall said.