Knowledge Transfer Task Force

Article 7 - Food safety truisms: trust but verify

June 17, 2019

Related Resources:
Danyluk - Pathogen transfer risks associated with specific tomato harvest and packing operations
McLandsborough - Survival, transfer, and inactivation of Salmonella on plastic materials used in tomato harvest
Strawn - Control of cross-contamination during field-pack and retail handling of cantaloupe

This article originally appeared in The Packer, and is reprinted here with permission. © 2019 The Packer

With the perishable nature of fresh produce, strong buyer-supplier relationships are critical to successfully get our foods from field to table. Every link in our supply chain needs to be able to trust that our trading partners are doing the right things, ensuring that the fresh produce we supply is both wholesome and safe. That said, verification is a necessary step in building long-term relationships. This includes reviewing annual food safety audits and corrective actions, conducting unannounced audits, and visiting farms and facilities throughout the supply chain on a regular basis.

Why verify? In every business relationship, we need to hold each other accountable until trust builds over the long term. Are your suppliers keeping up with the latest in food safety research and applying those research findings to their food safety programs? Do their documented practices match up with reality? Are you as a buyer knowledgeable of the latest science and current production best practices? Do you know what to look for in your suppliers’ produce safety programs?

Michael Spinazzola, president at Diversified Restaurant Systems, can personally speak to the value of using verification to build trust. For over 20 years, DRS has worked with Independent Purchasing Cooperative, a Subway franchisee-owned company, to develop strategic procurement plans for fresh produce for over 27,000 Subway restaurants in North America. Food safety has always been a mutual strategic priority for DRS and IPC, since any incident would affect the health and wellbeing of stores’ consumers and ultimately the overall Subway brand.

So, DRS strives to work as directly as it can with their supplier partners — the growers, shippers and repackers who provide tomatoes, onions, peppers and other items that are cut in-store, and the processors who wash and pre-cut items such as lettuce and spinach. If the Food and Drug Administration calls on Subway for trace-back information, the agency will need all details from the store level down to the grower level and that transparency along the supply chain is critical.

Close collaboration with Katia Noll and her food safety team at Subway HQ in Milford, Conn., has given DRS a solid foundation of knowledge upon which to develop partnerships with suppliers who prioritize food safety. Katia’s team manages the stringent food safety requirements and guidelines for the produce program, and then works with DRS and suppliers to understand any challenges, help communicate and educate the supply chain on Subway’s requirements, and stay up to date on industry developments and innovations. DRS helps verify that the selected supply chain partners are adhering to Subway’s standards on a regular basis by conducting their own mock recalls, collaborating with Subway’s team to develop a robust audit database system, and engaging with suppliers’ food safety experts to understand any unique challenges.

“Although every farm and facility is different, growers generally focus on the three Ws: water — are sources and application methods understood; wildlife — are there signs of animal intrusion; and workers — are they following Good Manufacturing Practices (GMPs) and hygiene standards,” Spinazzola says. Documentation is also key in developing a culture of food safety. Although audits are a snapshot of only one moment in time, they help verify ongoing documentation and education of the workers, to help safeguard against food safety risks.

Spinazzola notes that thanks to the work of the Center for Produce Safety to answer the produce industry’s specific food safety questions, DRS and Subway’s food safety knowledge has changed much over the past 11 years, and hence so have their expectations of suppliers’ practices. He recalls some old industry practices, such as harvest workers wiping dirt off the tomatoes with old rags that they kept in their pockets. There were no portable bathrooms in the field back then, either. Often, field cartons were used again for the final pack, even if they were moist or dirty. Now, a culture of food safety is becoming the norm, and going forward, the expectation for food systems will be on prevention and identification rather than reaction.

Spinazzola, a member of CPS’s board of directors, and his food safety staff have followed CPS research closely over the years. He points to two studies, for example, that indicated the need to change industry practices. 2012 work by University of Florida’s Michelle Danyluk, Ph.D., evaluated pathogen transfer risks specific to tomato harvest and packing operations. She found that using moist rags and/or used dirty cartons could transfer pathogens to fruits, while storing fruit in cold rooms could extend the life of Salmonella present on it.

A 2013 study led by University of Massachusetts-Amherst’s Lynne McLandsborough, Ph.D., evaluated the survival, transfer and inactivation of Salmonella on plastic materials used in tomato harvest. Interestingly, the efficacy of sanitizing older, abraded plastic field totes wasn’t much different compared to sanitizing new totes. The presence of soil on totes was much more likely to contribute to the persistence of bacteria. In addition, when workers used vinyl or nitrile gloves, less bacteria was transferred to tomatoes than when they wore gloves made of latex or polyethylene materials.

While those researchers studied tomatoes and cantaloupe specifically, their findings are generally applicable to all field-harvested commodities. Both studies highlight the importance of having effective — and current — standard sanitation operating practices of SSOPs, Spinazzola stresses.

Subway and DRS drive change by fostering relationships with its supply chain partners. Spinazzola reports they generally find that growers want to improve, and the restaurant industry — specifically large global brands such as Subway in particular — has a vested stake in helping them to do so. He cites one example when a tomato producer would not invest in heating equipment to raise wash water temperature to needed levels. DRS’s persistence and financial support finally turned the dial for that supplier to make the required improvements.

That said, Spinazzola also notes that an ongoing challenge is small local growers who are only in production for a short period of time each year. Those growers may need even more help, he says. Large or small, investing in food safety translates directly to safer foods for consumers, which is an investment in every company’s brand, says Spinazzola.

“Overall, our food is much safer than it was 10-15 years ago largely due to CPS and other research — but we need to take it to the next level,” he says.  “We need to ensure our food safety staff have the resources and tools they need, and that they keep up with the latest research developments. It’s going to take all of us to move the needle toward food safety improvements.”

Like DRS and Spinazzola, food safety is always top of mind with Wegmans Food Markets and Dave Corsi. Corsi is Wegmans’ vice president of produce and floral, and he is chairman of CPS’s board of directors. At Wegmans, food safety is the first discussion the company has with potential suppliers before deciding to do business with them.

Corsi and Wegmans’ food safety team also look to CPS research to help them “trust but verify” their produce food safety requirements of suppliers. Corsi points to the 2017 work of Laura Strawn, Ph.D., on controlling cross contamination during the field packing and retail handling of cantaloupes. One of her key findings was that foam used in display cases could be a harborage site for listeria.

Corsi urges every industry member to look to the knowledge base that CPS has amassed in the last decade, and consider where that research tells us that change is needed across the supply chain. Over the past 10 years, CPS has invested $26 million on 154 research projects, deploying contributions from private companies and government alike. The CPS Technical Committee identifies research priorities each year, then goes through a significant process to vet each research proposal CPS receives.

Researchers present their findings to industry at CPS’s annual Research Symposium. I invite you to join us June 18-19 in Austin, Texas for this year’s symposium. You can also search CPS’s research database, and review previous symposia’s key learnings, at

We all need to ensure that our business partners follow current food safety practices, and working together we can provide safer produce to our end consumers. Trust, but verify, means a brighter future for every link in our supply chain.