Risk is the sum of probability and seriousness, less the preventative and contingent actions taken to reduce it.

To get all math about it:

Risk = Probability + Seriousness - (Preventative Actions + Contingent Actions)

In the context of food safety for fresh produce, it's easy to forget this. So many resources spell out the things we can do to mitigate risk - from washing your hands and keeping food off the floor to using sanitized pallets and requiring workers to bathe daily - without providing any context about the probability of contamination.

Prevention in food safety comes down to keeping the poop off of the food. Preventative actions vary in their effectiveness. For my money, good hand washing - thorough scrubbing in running potable water with soap and drying with a single-use towel afterwards - provides the single biggest risk reduction. Everything else (except not dumping raw manure on your vegetables) pales in consideration.

Operating under the assumption that our produce is contaminated, we take contingent actions to keep the bacteria from spreading or growing. Washing in running water, sanitizing wash water, and cooling produce to slow enzymatic activity all reduce risk.

Of course, the seriousness of a food safety outbreak is high - E. coli 0157:H7 and Salmonella enterica can kill people. But the probability is relatively low - in the 2006 spinach - E. coli 0157:H7 outbreak, only three people died, and a couple hundred were sickened, despite over 250 billion servings of fresh bagged salad greens having been sold in the United States that year.

Effective food safety plans leverage preventative actions that are relatively straightforward and common sense to reduce the risk of a contamination incident, and back them up with contingent actions that reduce the risk of a single contamination incident spreading or multiplying.

When you are considering a food safety plan for your farm, focus on those preventative and contingent actions that yield a high return. A series of one-percent reductions in risk will add up, but you get far more bang for your buck by focusing first on those actions that yield big results.

The proposed Produce Rule for the Food Safety Modernization Act seems to be circling around out there, creating a lot of concern for some folks and not getting much notice from anybody else.

Despite the exemptions contained in the Tester-Hagen amendment to the legislation passed by Congress in 2010, many operations large and small are going to fall under the legal oversight of the Produce Rule or the Preventive Controls Rule.

Exemptions to the rule are based on a number of factors, including total food sales, the production of certain crops (including rutabagas), the kinds of customers you sell your produce to, and where those customers are located. The Produce Safety Alliance put together a one-page decision tree for determining an whether an individual operation will be exempt from the Produce Rule – you can link to that document here.

Do take note that just because an operation is “exempt” from the Produce Rule does not exempt that operation from meeting minimum federal requirements. You still can’t sell adulterated foods, and exemptions can be withdrawn if your farm products are linked to a food contamination outbreak.

In addition, if your operation buys in produce, you could fall under an additional set of regulations, the Preventive Controls Rule, with its own set of exemptions and timelines for compliance.

While the rule is still in the “proposed” phase, 2013 is not too soon to start working towards compliance. This doesn’t mean that you have to get all the way there in just once year, but it does take time to assemble and implement a food safety plan for a fresh market vegetable operation. At a minimum, developing an awareness of food-safety best practices this growing season will help even if you do the heavy lifting of operational changes in the winter.

I’m tired of hearing about how local food is fresher than produce trucked in from California, Arizona, and Mexico. “Freshness” relates to the amount of biological activity that has occurred from the time of harvest to the time a vegetable is prepared in your kitchen. Local food can provide tremendous benefits to a community’s economic vitality, to the flavor and selection of produce, and to a more-secure, less-carbon-outputting food system; but freshness is not a fundamental quality of locally-grown produce.

When I started Rock Spring Farm, I went to a meeting of growers for local food producers in Decorah at which the produce manager of the local natural foods cooperative commented that the lettuce she purchased from local producers didn’t last very long, while the produce from California had a shelf-life of a week to ten days. I had experienced the same thing with local produce on a farm I managed in Maine, and it all comes down to temperature. In both of those times and places, local growers hadn’t invested in the equipment and systems necessary to maintain produce quality.

Within the range of temperatures where plants survive, the rate of chemical and biological processes approximately doubles for every ten-degree increase in temperature. That means that produce stored at 45 degrees will last half as long as produce stored at 35 degrees; and produce stored at 55 degrees will last only a quarter of the time. When we pick a vegetable, we separate it from the source of energy and sustenance that comes from having its extensive network of roots expanded throughout the soil – at this point the portion of the plant we’ve picked begins the process of dying, which in vegetables is characterized by a decline in “freshness” and quality.

Getting produce cooled to the proper storage temperature is the first essential step in ensuring freshness; keeping it at the proper temperature is the second. The large-scale production systems in the vegetable-producing regions of this country dedicate a tremendous amount of infrastructure and energy to getting produce cold and keeping it that way. It is not unusual for a harvest operation to include refrigeration units right in the field, climate-controlled packing facilities, and refrigerated transportation from harvest right to the point of sale.

Furthermore, it’s not just the air temperature of the storage environment that matters – it’s the interior temperature of the produce. Grocery store coolers and home refrigerators do not have the power they need to actually suck the heat out of warm produce – that needs to be done by the farmer. And dunking in cold water (ground water comes out of the tap at around 45 degrees on the Iowa-Minnesota state line) and storing at ambient temperatures just can’t do that.

At Rock Spring Farm, we’ve invested in the cooling facilities and harvest systems that get produce cooled quickly, and keep it cold until it’s sold. Whether it’s planning for harvest to allow time for equipment to cool the produce, our rapid harvest techniques and shading in the field prior to transport to our insulated packing facility, adequate potable water to provide a continuous supply of cold water for initial cooling, our commercial-grade walk-in cooler, or the cold chain our delivery partners maintain throughout the delivery process, we work hard to ensure that vegetables will stay alive – and stay fresh – for as long as possible.