The emptied-out produce shelves greeting consumers at grocery stores after the recent romaine lettuce E. coli outbreak show just how much work lies ahead to modernize the nation's food safety laws.

In retrospect, passing a landmark regulatory overhaul eight years ago was the easy part. That law, the Food Safety Modernization Act (FSMA), was signed into law in early 2011. It was rightfully heralded by the Editorial Board and other observers as providing some of the most important new consumer protections in decades. The previous food safety regulations too often dated from the horse-and-buggy era.

Turning the legislative language into working regulations is always a challenge, but the U.S. Food and Drug Administration (FDA) faced an especially daunting undertaking with FSMA's sweeping reforms. Still, the agency has to do better. The recent E. coli outbreak linked to romaine lettuce — the third in the past year — put an alarming spotlight on two key areas where implementation still lags years after FSMA's passage:

• Traceability. Swiftly working backward from consumers who get sick to the source of the contaminated produce they ate is critical to halt outbreaks. FSMA put forward an aggressive timeline of two years for enhanced record-keeping to better trace high-risk food through the supply chain. This regrettably hasn't happened yet even as technology has advanced to allow faster, more precise digital tracking instead of the paper records still often in use. This lack of speed and precision left authorities no choice after the recent E. coli outbreak but to pull all romaine off the shelves instead of targeting lettuce from affected producers or fields.

• Water quality. FSMA also called for agricultural water safety standards to guard against pathogens that can be transferred to produce through irrigation, pesticide application or packing. The source of the current E. coli outbreak has not yet been identified. But available evidence suggests the likeliest source of another outbreak linked to the lettuce earlier this spring was contaminated irrigation canal water. Unfortunately, delays in implementing the law's new water standards have continued since the Obama administration — mostly due to producers' concerns about cost and effectiveness — and may not be in place for most produce until 2022 at the earliest.

Food safety advocates such as Sandra Eskin of the Pew Charitable Trusts merit praise for pushing for improvements, particularly on traceability. An editorial writer's interview this week with Dr. Stephen Ostroff, the FDA's deputy commissioner for Food and Veterinary Medicine, suggests that the agency is listening.

Ostroff, who is leaving the post soon, will be replaced by a Walmart executive with expertise in wielding digital technology to better track produce. Ostroff wouldn't designate a time frame for new traceability improvements but said the FDA is looking to "accelerate" the effort. Agency leaders also need to lead on communicating with producers what information is needed when an outbreak occurs

Ostroff said improving agricultural water quality is a priority, as well. A new task force will look at this issue. Its agenda should include short-term options to improve safety before the new water standards take effect. An example: treating water before it is used on produce. The agency should also strongly consider whether FSMA water standards could be implemented sooner.

The industry and the FDA have admirably collaborated on new labels to help consumers identify romaine lettuce's harvest location and date. Currently, health officials only advise against eating romaine from Central California, or if the produce's source cannot be determined.

The new labels are a welcome step, but there's much more work to be done. So far, 43 people in 12 states have been sickened in the latest outbreak. Strong, swift action to fill FSMA implementation gaps is vital to reduce the risk of the next one.