Screening Doors

Departments - Practical QA Solutions

April 4, 2019

Open or poorly screened doors have been a problem in the food industry for many years leading to food contamination and failed inspections.
OLE DOSLAND, QA & Food Safety Consultant, Certified Instructional Designer/Professional Instructor

Many food storage facilities, including distribution centers, do not have adequate air flow and ventilation causing discomfort for workers in hot weather. Letting in clean fresh air is necessary and should be done in a manner that protects workers, food, and property. Poorly screened doors are a food safety and pest exclusion problem in food storage facilities.

For example: One bird dropping creates unimaginable consequences. Most stored product insects are good fliers. A rodent urinates as it travels and produces 50 to 100 fecal droppings daily. Airborne foreign material on food products is an indication of other contaminates. A rat can enter a building with an opening of one inch, a mouse ¼ inch and an insect 3/100 inch.

As birds, insects, and rodents are known to carry foodborne pathogens such as Salmonella, their prevention is an essential prerequisite for a successful food safety program.

The Food Safety Modernization Act (FSMA) enables FDA to focus on preventing food safety problems rather than reacting to them after occurrence. And the agency is doing so: A large food distribution center was visited by FDA to investigate a problem that had come to its attention. The distribution center held damaged food in a designated area for rework. The FDA investigator observed open food packages, rodent droppings, and filth in the rework area near a trash compactor and a poorly screened dock door. Openings were observed on each side of the screen with a dead rat found inside a nearby rodent catch device. The screen was partially open with airborne foreign material drifting into the building and rework area.

At the conclusion of the inspection, FDA issued a Form 483 to the facility’s management noting that these conditions constitute violations of the Food, Drug, and Cosmetic (FD&C) Act. A lawyer prepared an action response, but the distribution center’s file was now blemished.

Any food storage facility should realize that one bird, one insect, or one rodent is one too many, dead or alive. Letting pests enter for capture inside is not acceptable and letting airborne foreign material inside is an indication of a bigger problem. Why is screening doors so difficult? What does it take to do it right? What is a practical solution?

In many food warehouses and distribution centers a screen door is utilized as an air intake filtration device helping to improve overall air flow. The optimal screen opening is of a size that allows a majority of air in, but keeps the highest majority of pests and foreign material out without creating an impractical cleaning activity. Regular cleaning of a screen door is expected and should be done from the outside. The screen material must be durable to withstand this cleaning activity as well as the day-to-day activity.

Why are screens positioned inside a door? Stopping nature inside allows parts of nature inside. Why do screens not seal all the way around? Small openings will be found by birds, insects, and rodents. Why are screens susceptible to puncture/tear? Tiny openings will be found by tiny insects, and rodents are excellent climbers and will find their way through small openings. Why don’t screens rapidly go up and down? Many screens are not closed because of inconvenience to workers. Why don’t screens last over time? Poorly designed screens and framework are susceptible to damage.

A practical solution is to let air in and keep nature out with an automated exterior mesh screen door with a 100% seal, including brush weather seals on tops, sides, and bottoms, with a tear-resistant material mounted on a rigid dock frame.

One bag of infested food can ruin tons of safe and wholesome food. Numerous foodborne diseases are caused by pest activity in food processing and storage facilities. Denial of pest entry is an essential prerequisite for food safety and IPM programs.

Open or poorly screened doors have been a problem in the food industry for many years leading to food contamination and failed inspections. It is imperative that storage facilities in the food, pet food, and feed industries keep doors closed or screened properly.

It is only a matter of time before all food storage facilities in the food, pet food, and feed industries, including food plant warehouses and distribution centers, are visited by FDA. Many facilities are not ready and might face consequences of open or poorly screened doors. It should not be this way.