MSU Extension

View a PDF version of this resource for Episode 14 of Agrifood Safety Minute

Clean and sanitary harvest containers are critically important in harvesting crops that are consumer-ready. They also can help decrease post harvest losses from scratches and soiling on sensitive products like peaches and summer squash. 

This guidance document addresses the steps to sanitary cleaning and offers a number of different standard operating procedure (SOP) boilerplates that can be adapted to your farm and help you write a standard operating procedure.

 There are four steps to cleaning any surface that contacts food. The surface must be prerinsed to remove soil, washed with soap and water, rinsed of soap and water then sanitized. If you use disposable, single-use harvest boxes, they do not need to be washed and sanitized. If you use any reusable containers such as plastic lugs or buckets, they must be sanitized prior to being filled with produce. 

The first part of a harvest container SOP specifies all types of harvest containers used, then delineates those that are single use from those that are reusable. If a grower was only using single use harvest containers, the container cleaning SOP would end at this point, since single-use containers pose little risk of contamination. The items in parentheses must be customized for your operation. 

Harvest Container Cleaning SOP

Reusable (five gallon buckets, lugs, plastic bins) containers and one-use waxed card-board boxes are used to harvest produce from fields. All reusable harvesting contain-ers are cleaned at the end of their use through the same four-step process every time.

Then the SOP needs to clearly describe the steps to cleaning the containers. If you use a power washer for the prerinse, wash and rinse steps, it needs to be written in the SOP. 

Any detergent can be used for the wash step as long as it is food safe. Use of an antibacterial detergent does not replace the final sanitizing step. 

• Step One: (Your reusable harvest container type) are pre-rinsed with water to remove visible soil particles. 
• Step Two: (Your harvest container type) are then washed with dishwashing or similar soaps applied to the surface, either in dispersion or directly, to break down contami-nants and soil. A brush is used to scrub the containers while they are soapy to further remove soil and other possible particles from the inside and outside surfaces. 
• Step Three: (Your harvest container type) are then rinsed with water to remove soil particles, contaminant particles and any soap residues. 

Sanitizing the containers can be done with a number of products. Some, like hy-drogen peroxide, are approved for organic production. Others, like bleach or quater-nary ammonia, are not organically approved. 

Whatever sanitizer you use will require some monitoring on your part to ensure there is adequately available active ingredient. In the case of chlorine bleach, this is done using test strips to ensure at least 100 parts per million of free chlorine. You will need to specify both that you test for free chlorine and how often. In the case of a hy-drogen peroxide sanitizing preparation, you’ll want to specify that the product is used according to label recommendations. The SOP excerpt below details both of these options. 

• Step Four: (Your harvest container type) are sanitized with Storox (hydrogen peroxide). Hydrogen peroxide solution (6% w/w) is applied to the inside and outside of the con-tainers to sanitize them according to label recommendations to maintain 300 parts per million.

Or

• Step Four: (Your harvest container type) are sanitized with chlorine bleach. Bleach so-lution (10% by volume) is applied to the inside and outside of the con-tainers to sani-tize them. Periodically, the bleach solution will be monitored for free chlorine to ensure a minimum of 100 ppm of free chlorine.

As always, SOPs must be customized for the type and scale of operation. In addi-tion, the auditor is looking for evidence of a system written in the GAP Manual to mini-mize incidence of foodborne illness, visual evidence that it is taking place and docu-mentation that it has been taking place in the past. Writing the SOP is the first step. Implementing the practices on your farm is the next step. Documenting the cleaning of bins and the proper use of sanitizer is the final step.