What role can packaging play in food safety?

Currently, the role of packaging in the fresh produce industry is primarily one of optimizing food quality rather than focusing on food safety, industry experts say. The food safety work is usually done prior to the food entering the package

But that could change as packaging research progresses.

Produce packaging primarily is designed to protect the quality of the produce by fighting plant pathogens that cause the product to deteriorate, not to ensure the safety of the product by attacking the human pathogens, like E. coli, salmonella and listeria that can harm people, said Jeff Brandenburg, president of the Qfresh Lab/JSB Group, a Marina, Calif.-based international testing laboratory and consulting company that specializes in packaging design.

While packaging can protect food from spoiling, spoiled food is primarily a quality issue, rarely a food safety issue, Brandenburg said. It’s not likely to make you sick.

One way packaging does play a food safety role is by preventing cross contamination.

“Packaging does a great job of keeping what’s in in and keeping what’s out out,” Brandenburg said.

It also can help prevent tampering.

Gretchen Wall, director of food safety and quality for the International Fresh Produce Association, agreed with Brandenburg.

“Packaging really is not a solution for food safety, it’s more for the protection of produce from the physical standpoint and to maintain the shelf life of the product,” she said.

“Introduction of foodborne illness causing pathogens must be prevented because fresh fruits and vegetables do not have a processing kill step.”

It’s nearly impossible to achieve total elimination with sanitizers or other packaging technologies once pathogens are present, she said.

“Growers and distributors should consider how they package commodities to limit introduction of any sort of chemical, physical or microbiological hazard through the supply chain, even if they’re being shipped in a large container,” Wall said.

This might include being cognizant of how bins or totes are stacked to reduce the chance for contamination to impact product stored below, keeping product covered, when possible, during transportation from the field, or storing iced product in a different area than non-iced product with proper drainage, she said.

From a quality standpoint, packaging protects fruits or vegetables from physical damage, like bruising, which could enable substrates to be available for bacterial growth or spoilage organisms that might cause produce to decay more rapidly and therefore reduce its shelf life, Wall said.

There are some new technologies that alter the environment within the package by modifying the atmosphere or releasing agents that create conditions that are not ideal for pathogens or bacteria to grow, she said.

“These types of technologies should not be a substitute for good agricultural practices in the field but can be used as an additional hurdle for managing microbial growth.”

Indeed, there are a number of packaging formats and options that might enhance food safety that have not yet penetrated the industry, said Trevor Suslow, extension research specialist emeritus at the University of California, Davis.

For example, microbial coatings have been researched for use on the inside of corrugated cartons and bins, he said.

Silver ions embedded into plastic as an internal coating would prevent the development of persistent contamination, he said.

Some initiatives involving plant-based antimicrobials like chlorine dioxide can reduce risk to some degree in bags and master cartons have been around for a while, but they don’t seem to have gotten much traction in the industry, he said.

Antimicrobial packaging can serve as food safety solutions, but they’re often not practical for the fresh produce industry, Brandenburg said.

Antimicrobial packaging incorporates agents that can kill microorganisms into the film of the package.

“On contact, bacteria would die,” Brandenburg said.

The problem is that, with fresh produce – leafy greens for example – not much of the product actually comes in contact with the surface of the packaging.

Other technologies allow gases to be released that basically fog the inside of the package.

“Those are available, and they’ve been experimented with for a lot of years, but one of the problems with them is they can be expensive, and they have certain regulatory controls around them,” Brandenburg said.

There also are some natural antimicrobials, like certain spices, but they tend to alter the flavor of the produce.

In some cases, defective packaging actually can increase a food safety risk, Brandenburg said.

For example, although modified-atmosphere packaging for fresh produce is primarily “a quality, shelf life extension technology,” it can exacerbate a food safety risk if not designed properly.

“If it’s not done at a proper temperature, or if it’s not designed properly, then the package can go anaerobic – meaning the produce can consume all of the oxygen in the package,” he said.

“In that case, if you’ve got pathogenic bacteria present, they can proliferate faster.”

“There is an intersection of quality and food safety where you want to create packaging that improves quality and extends shelf life, but you have to make sure you do it right or you can create an atmosphere that actually can exacerbate a bad situation,” Brandenburg said.

Although food safety starts in the field, safety has to be maintained in storage, during distribution and where packing or packaging materials are staged, whether in a field, orchard or vineyard, Suslow said.

“The packing materials are going to come in basically free from food safety hazards,” he said.

It’s important to keep reusable plastic containers, corrugated cartons or various types of plastic films free from chemical or microbiological contamination.

There have been instances where packing materials staged at a field location overnight or for a couple of days in advance of use created a food safety risk from airborne materials, vectors, vermin or and pests, he said.

“There is a pretty low risk level, but it’s something to be aware of,” he said.

He also advised keeping packaging materials dry.

“Water is the enemy” that could allow for growth of things like foodborne pathogens, he said.