Food safety can begin before a plant is built

May 11, 2007

Sanitary design is a holistic approach to creating an environment that will reduce the risk of contamination in a fresh-cut produce facility. It covers the local environment, the construction and maintenance of the facility, education of employees and workflow. Sanitary design should begin before a processing facility is built.

Exterior Design

“Sanitary design starts with the site design of where you’re going to put the building,” said Les Lipschutz, principal of Food Safety Inc. in Albuquerque, N.M.

A facility that’s been built in a flood zone could become contaminated if the water rises – puddles create a risk of growing bacteria and tracking them into a facility. Dust from dirt roads could carry organisms into a facility.

Activity at neighboring buildings should be considered as well, said Don Graham, consultant and owner of Graham Sanitary Design Co. in Jackson, Mich. The plant’s design will have to be amended if it’s to be downwind of a treatment plant or any noxious fumes. If there are no natural barriers, then the building’s air treatment system needs more attention and positive pressure is more important.

“It depends on what’s between you and the effluent,” Graham said. “If you have a neighbor putting out noxious fumes, no one’s going to tell him not to do it. You have to make provisions for that in your plant.”

What is to be processed in the plant also should be considered during site selection. It should be near to the growing operation to reduce damage to the produce during transport, Lipschutz said. Ideally, growers and the fresh-cut facility should be near the major metropolitan area that the plant will be serving. That will help extend the shelf life by reducing the amount of time a product is in refrigerated transport.

The exterior of the facility shouldn’t be forgotten once the plant has been built. Landscaping can be a route to contamination, Graham said, so measures should be taken to reduce animal or debris contamination.

Trees should be no closer than 30 feet from the building and away from walking paths to prevent birds from flying in and bird droppings being tracked in.

Bushes should be cleared back so they don’t touch the building because they can harbor rodents or other pests.

The facility’s roof should be a single membrane, not tar and paper, which collects dust and debris that could make its way into the processing area.

Chemical applications on landscaping near loading areas should be closely managed to prevent raw or finished product from becoming contaminated. Chemicals shouldn’t be a problem anywhere else on the grounds if there is a good positive pressure environment inside.

Interior Design

The goal of sanitary design is to create an environment that is cleanable, Graham said. That means eliminating nooks and crannies that can collect debris and anything absorbent that can collect moisture. Walls should be smooth so they can be cleaned easily and should be left unpainted to prevent paint chips from getting into produce.

The standard for fresh-cut processing is a “building within a building,” with positive pressure ventilation in the cutting and cleaning area.

“You need clean air,” Lipschutz said. “Otherwise, you’re basically shooting yourself in the foot.”
The ventilation system should include a filter that blocks almost all particles that could carry living organisms.

“The standard we’re recommending is 95 percent efficiency at five microns,” Graham said. “Most dust particles are larger than five microns.”

Of particular concern in a fresh-cut facility is the control of condensation. Any time moisture accumulates and drips, it’s a food safety hazard.

“In HACCP, that’s an automatic failure,” Lipschutz said.

Condensation is the suspected cause of the February outbreak of Salmonella tennessee in peanut butter. Other bacteria can be spread by water and condensation in a fresh-cut plant.

“Condensate is always bad, especially in a chilled environment, because listeria loves it,” Graham said.

A properly functioning ventilation system will remove humidity from the air, but water can accumulate from other sources. Lipschutz recommends checking high-pressure water systems for leaks that can create aerosols.

A second way to control condensation is to get rid of poorly designed areas that water droplets could cling to. Overhead machinery should be carefully sanitized by the crew, and open ceilings should be covered over, if possible.

Many plants have pipe runs, lights and electrical systems overhead, and they are candidates for bacteria buildup and condensation. Rounding off flat surfaces above is an easy solution, but a better one is enclosing the ceiling with solid construction, Graham said. That will make it easier to clean and eliminate a number of food safety obstacles. He called it a “room within a room” that can be accessed from elsewhere in the plant to service the water or electrical lines, or even change light bulbs. Don’t use a drop ceiling, Graham said, because that only provides more areas for water to accumulate.

Walls also contain collection areas that can easily be fixed. The Z-bars on the walls usually have U-shaped brackets that should be facing down. Lipschutz said these are often installed facing up, and they are difficult to clean.

It may be helpful from the beginning to enlist the services of an expert in food safety to fix any flaws before they become serious.

“I don’t usually get involved until the building is already up and there’s a problem,” Lipschutz said.

Increasing Efficiency

Sanitizing teams, while important for food safety, don’t make money for a fresh-cut processor. They’re a cost center, Graham said, and in an increasingly competitive market, companies are looking to reduce their cost centers. That has led some to try sanitation regimens that are not completely effective, such as “rolling cleanings,” where parts of the line continue to run while the sanitation team cleans another part.

But a good sanitary design will allow the cleaning team to work faster and more efficiently, thereby extending the production time on the lines. Not only that, but properly designing a fresh-cut plant will reduce the chance of airborne or waterborne contaminants entering the food chain during the processing stage, and consumers can be confident in the safety of their fresh-cut produce.