Considering the flow of food in pack shed design

Early in the process of planning a pack shed, think how food moves from harvest until it leaves the care of the operation. Tracing the flow of food helps pinpoint potential sources of contamination that might not otherwise be apparent.

A design of a pack shed.
Photo by MSU Extension

If you are a fresh produce grower who is planning to build a new pack shed, it might help to start by following the food. The first step in any risk assessment is to follow the produce from the time it’s picked until it leaves the care of the farm. Food safety types call this a process flow. A process flow breaks down every step of the journey from the ground to the table. This process flow serves as a back-bone for all risk assessments. It can also guide a grower on how to set up a new pack shed.

Does the food ever move into an area where a biological, physical or chemical hazard can come in contact with it? If the flow of food passes through areas where crop protectants or fertilizers are mixed and loaded, those residues could contaminate the crop. If the area is near diesel loading and storage areas, this could also pose a contamination risk.

Staging areas in the shade under trees or awnings seem to be a pretty safe place to stage the produce prior to bringing it in for grading, washing or packing. The shade is also conducive for roosting birds that could pose a food safety risk. Power lines are also popular roosting sites for birds. Pay attention to paths the food takes that have it staged around or passing under a possible physical, biological or chemical contaminant.

Is there ever a chance where a lug of washed and cleaned produce could get commingled with a lug of produce fresh from the field and not yet washed? Often, space is at a premium in wash-pack areas or coolers. These spaces often have to accommodate both clean and dirty produce. The flow should be arranged to minimize the chances of the two getting mixed.

Following the food could take the form of an actual map. Mapping the path could allay some fears and bring to light areas of concern. Those individuals designing a new packhouse should plan on creating a map of the packhouse and draw the flow of food on that map before the first shovelful of dirt. It’s hard to make changes to things like concrete after they harden.

For more information on packhouse design, tune in to a monthly YouTube video series that chronicles a farm as it plans and executes the design and construction of a new packhouse. The first installment of the series can be found here: Building a Wash & Pack Shed: Get to Know the Farm.

If you would like more information on packhouse design or implementing good food safety practices in your operation, contact the Michigan State University Extension Agrifood Safety Work Group at or 517-788-4292.

Funding for this article was made possible, in part, by the Food and Drug Administration through grant PAR-16-137. The views expressed in the written materials do not necessarily reflect the official policies if the Department of Health and Human Services; nor does any mention of trade names, commercial practices or organization imply endorsement by the United States Government.

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