New research targets unseen paths foodborne illness takes to consumers

Foodborne illness continues to pose a major public health challenge in the U.S., sickening an estimated 48 million people each year, according to the U.S. Food and Drug Administration.

At Texas A&M AgriLife Research, two scientists within the Department of Food Science and Technology at the Texas A&M College of Agriculture and Life Sciences, are developing complementary strategies to reduce that risk by addressing how pathogens enter the food supply and how processors can eliminate them before products reach consumers.

Their work spans fresh and fresh-cut produce, beef carcasses and processed meat products, and the global systems that connect them.

Tracking pathogens from field to packing line

Alejandro “Alex” Castillo, Ph.D., who also has an appointment in the Department of Animal Science, studies how pathogens such as salmonella, E. coli and listeria contaminate food through everyday production and processing – not through intentional tampering, but through everyday breakdowns in sanitation and handling.

“As soon as you start producing or processing foods, if you don’t follow specific procedures, you allow naturally present hazards to develop or remain in the food in a way that makes it to the consumer,” he said.

Castillo’s research spans the U.S. and Latin America, where much of the fresh produce consumed in the U.S. is grown.

Avocados are a major focus of his work. As many as 90% of the Hass avocados eaten in the U.S. are grown and packed in Mexico. That large volume creates opportunities but may also increase the risk of contamination entering the supply chain.

In a recent binational project, Castillo and colleagues at the University of Guadalajara swabbed equipment, floors, walls and storage areas in avocado packing plants to detect generic listeria species. These organisms serve as indicators of where the pathogenic species, Listeria monocytogenes, could survive.

Each month, Castillo’s team sequenced the DNA of isolates to determine whether they were transient strains arriving from the field or resident strains that had become established in the facility.

In one plant, the same strain appeared on surfaces, equipment and utensils, and in a storage room, suggesting it had taken root and spread through cleaning tools and plant movement. The team used those findings to recommend targeted sanitation and procedural changes.

Castillo’s lab also tests intervention technologies designed to eliminate pathogens that survive routine sanitation. In partnership with a colleague who discovered natural antimicrobial compounds within avocado tissues, his team developed edible coatings that can reduce listeria on fruit surfaces.

“We have very good results, and we are continuing,” Castillo said.

Looking ahead, Castillo aims to continue this work by enabling scientists to test packing processes with industry-scale equipment, explore safer alternatives to traditional brush systems, and evaluate real-world contamination scenarios.

Building safety models for meat, poultry and rendering

A few buildings away, Matt Taylor, Ph.D., a professor of food microbiology in the Department of Animal Science and a member of the graduate faculty in the Department of Food Science and Technology, focuses on helping meat and poultry processors validate that their production steps effectively eliminate dangerous pathogens.

His lab collaboratively develops mathematical and machine-learning models for products such as fermented and dried salami, which may not undergo a conventional cooking step.

“There’s not really a well-known validated model out there that can determine the safety of these foods, especially when cooking is not employed in the food’s manufacture,” Taylor said.

His team is compiling existing models, generating new data on pathogen inactivation, and building a comprehensive tool that processors of all sizes can use to meet food safety requirements.

Taylor’s earlier work supported the rendering industry, which transforms inedible animal byproducts into materials used in pet foods and fertilizers. By inoculating raw rendering materials with pathogens and monitoring their survival under different heating and holding conditions, his team helped the industry demonstrate compliance with FDA requirements for eliminating biological hazards.

Taylor also collaborates with Castillo and colleagues in horticultural and chemical engineering departments on produce-safety research. Their joint projects include testing nano- and microencapsulated natural antimicrobials on leafy greens, melons and tomatoes, and evaluating tools and equipment in packing sheds to reduce contamination risks.

With support from the U.S. Department of Agriculture, they work with Texas A&M AgriLife Extension Service specialists and Extension specialists nationwide to help growers and packers implement validated, science-based safety practices. Together, Castillo and Taylor’s work reflects a systems-level approach to food safety, integrating microbiology, engineering, global supply chain awareness, and emerging technologies like machine learning to reduce risk before food reaches the table.