Caesar salad isn’t even the best salad.

It’s the kind of salad you expect at a sports team banquet or during lunch at an all-day meeting.

It’s a safe menu choice.

Except for the past month when foodborne illness outbreak investigators have focused on Romaine lettuce as the culprit of an outbreak of E. coli O157 linked to over 170 illnesses in 32 states.

E. coli O157 historically was once only associated with ground beef making it’s first appearance as what was thought to be a rare strain in 1982 after an outbreak was traced to McDonald’s. In 1993 over 500 illnesses and 4 deaths were linked to Jack-in-the-Box restaurants , an event that brought foodborne illness to the national stage. Fast forward 35+ years and the devastating pathogen has caused illnesses after being consumed in cookie dough, hazelnuts, alfalfa sprouts, soy nut butter, chicken salad – and a whole bunch of fresh produce including leafy greens.

The very type of food we should eat more of betrays us at a higher rate compared to other foods: Fresh produce is believed to be the source of almost half of all foodborne illnesses in the U.S.

Because it is consumed raw, anything that fresh fruit and vegetables come in contact with from the field to the home can really only increase risk. Washing and rinsing can remove at most 99% of what’s there. Microbiologically speaking, because there may be tens of thousands of cells on a leaf of Romaine, that’s not a whole lot. Often produce-related outbreaks are linked to poop getting into the food somewhere — wildlife on the farm; water used for irrigation or rinsing; soil and/or manure; or, the people who harvest, pack, handle and prepare it.

The problem with this outbreak is that the world of food safety sleuths have yet to figure it out. This one is particularly hard because the supply chain is a mess and  investigators are trying to piece together what the farms and packing facilities looked like, food safety-wise, retroactively. Partners in figuring out outbreaks, the U.S. Centers for Disease Control and Prevention and the U.S. Food and Drug Administration have only been able to trace the problem to a specific geographic location – Romaine that was grown in the Yuma, AZ region.

Having a good sense of the supply chain for food, so outbreaks and incidents can be solved, is something that the industry has struggled with for decades. Even with the increased use of electronic records and the promise of blockchain, the data that gets recorded and shared relate to location and how food safety is managed from production to distribution to the grocery store still relies on people to input it.

Better traceability is often held up as a magic bullet but can’t really stop outbreaks from happening alone. Being able to trace a product is wholly reactive. While it is part of a good food safety culture even a good traceability program doesn’t wipe raw poop off of foods.

What keeps food safe is vigilance by the food industry, learning from past outbreaks and focusing on carrying out best practices daily. Lots of food companies talk about food safety. Implementing it daily is much harder. It takes a system throughout the entire company from the front-line staff all the way to the CEO that values food safety. Everyone needs to understand why food safety matters, what their role is and care about the folks who eat their products.

Where I grew up, there was a small tailgate farmers market Saturday mornings in the parking lot adjacent to the grocery store. I never really wondered whether the food sold there was safe. I didn’t think a whole lot about food safety and regulation until years later. I figured that if someone could sell it, they must know what they are doing, and I didn’t have to worry about it.

Food safety is all about trust, and I had lots of it.

I still do.

But over 75 outbreaks linked to leafy greens since 1995 is eroding that trust.