When it comes to growing produce, food safety must be considered when making any decision in the process. At the Northeast Greenhouse Conference in November, Shirley Micallef from the University of Maryland led an educational session titled “Food Safety Issues When Growing Greenhouse/CEA Leafy Greens.”

Specifically, Micallef focused on comparing food safety in controlled environment agriculture (CEA) versus the normal outdoor agricultural environment. However, the term “controlled environment” is extremely broad, and could mean anything from the interior of a high tunnel to a full-tech facility where every step of the process, from the weight of the fertilizer to the temperature of the irrigated water, is controlled.

Overall, the main goal is to prevent any bacteria from entering the growing area, and excluding any that already have entered. There are a lot of factors at play that allow bacteria to enter the environment and thrive, including where you purchase your seeds, seed storage, seed treatments, crop recall plans, the types of substrate used, leaky water, and more.

Some advantages to utilizing CEA include optimal water, nutrient and light needs; controllable environmental conditions (temperature and humidity); reduced weed pressure; reduced macrofauna problems (no deer or other wildlife pests); reduced plant disease; reduced risk of airborne hazards; and reduced risks at harvesting. However, in CEA, you still have to worry about microbial water quality and air movement.

Micallef explained that there is “not enough data or experience to be able to compare the safety of field ag and controlled environment agriculture.” Specifically, more research must be done on CEA to have a strong comparison between the two.

At the end of the day, although there is not enough data to compare the food safety of CEA and outdoor environments, there are some best practices to increase your food safety in general. These practices include conducting agricultural water system inspections, considering water testing and treatment, identifying areas where cross-contamination may occur and properly training your workers to handle the crops and recognize potential problems.

by Kelsi Devolve