WASHINGTON (Reuters) – As more Americans get sick while health officials look for the cause of a salmonella outbreak sweeping the country, consumer groups said on Thursday the Food and Drug Administration must put emergency rules in place to track the movement of produce.

Food safety and consumer groups said traceability would make it easier for officials to track through the supply chain the origin of fruits and vegetables and identify the source of outbreaks of foodborne toxins, such as salmonella or E. coli, preventing more people from getting sick.

The Center for Science in the Public Interest and the Consumer Federation of America told reporters an effective tracking plan must follow the produce from the farm to the table, and use a single system that can ensure proper record-keeping throughout the process.

“If (the FDA) had put a traceability plan in place two years ago, following the spinach outbreak, this current investigation may be moving more quickly,” said Chris Waldrop, a director at the Consumer Federation of America.

“The latest outbreak clearly demonstrates the need for the federal government to be able to quickly and easily identify and trace an implicated food to its source,” he added.

Currently, U.S. health officials are struggling to find the source of a salmonella outbreak that has sickened at least 869 people and hospitalized 107 in at least 36 states.

Tomatoes are the primary focus, but officials have expanded the investigation to include other produce eaten with tomatoes.

David Acheson, FDA’s associate commissioner for food protection, said on Tuesday the process has been slow and admitted the agency needs to reexamine how it handles outbreaks.

This comes two years after an outbreak tied to tainted spinach. That E. coli outbreak killed three people and sickened more than 200. These incidents have prompted calls for change at the FDA.

The Center for Science in the Public Interest and the Consumer Federation said tracking technologies are already being used by produce companies, but the approach is voluntary and businesses are using different systems and approaches.

They also called on the FDA to require growers and others handling produce to have food safety plans for their businesses.

Bob Brackett, a senior vice president at the Grocery Manufacturers Association, said high-risk produce associated with illnesses — such as leafy greens, tomatoes and melons — should be targeted for traceability first, before moving to other fruits and vegetables.

“The idea is good, but it needs to be implemented where it is going to do the most for public health,” said Brackett.