Was it a contaminated bagged lettuce mix that caused a foodborne outbreak that has now made 400 people sick in 16 states, including Minnesota? Or was it something else?

More than a month after the first illnesses caused by a foodborne parasite known as cyclospora were reported in Iowa, state health officials there and in Nebraska released the results of their outbreak investigations last week. The culprit, according to them, at least, was a bagged salad mix that consumers could have been exposed to at restaurants or grocery stores.

Consumers normally can breathe a sigh of relief when health officials pinpoint an outbreak’s source. Products that likely made people sick will be pulled off store shelves and out of restaurants. Those who have become ill can connect the dots of what they’ve eaten and where they’ve eaten and get the medical care they need.

But last week’s bagged lettuce announcement by these states’ health officials inspired far more questions than confidence that the outbreak culprit has been nailed down and that the investigation is progressing as it should. The announcement also underscored public health experts’ growing concerns — former Minnesota state epidemiologist Michael Osterholm is among those sounding the alarm — about the investigation’s time frame, methodology and accountability.

Soon after Wednesday’s announcement, statements from the U.S. Food and Drug Administration and the U.S. Centers for Disease Control and Prevention suggested strongly that these leading food safety agencies aren’t fully on board with the conclusion reached by the two states.

While initial statements from both federal agencies were difficult to interpret — and looked like an attempt to save face for Iowa and Nebraska officials by glossing over differences — eventually, the agencies made it clear when contacted by an editorial writer that the outbreak has not yet been solved.

“The states of Iowa and Nebraska have announced the results of their analysis in their respective states. FDA has been working to combine the Iowa and Nebraska information with information collected from other affected states with the goal of identifying a specific food item linked to the illnesses,’’ said FDA spokeswoman Theresa Eisenman on Thursday afternoon.

Iowa and Nebraska officials’ refusal to name restaurants or the supplier that may have sold contaminated products also raises unflattering questions about whether these state health officials’ priority is protecting consumers or protecting industry. While Iowa officials cite state laws that limit them from naming businesses caught up in outbreaks, it appears they have leeway to do so if the information is needed to protect the public.

Given that this outbreak’s bug can cause severe diarrhea lasting for a month and can cause weight loss of 10 to 20 pounds, consumers should be given the information they need to determine if they’ve been exposed and need medical care. Twenty-two people have been hospitalized in the current outbreak.

On Friday afternoon, the FDA stepped into the information gap somewhat. While still saying only that the Iowa-Nebraska investigation had linked the salad mix to the outbreak, the agency said it had found that “illness clusters” at restaurants in those two states were traced to a common supplier, Taylor Farms de Mexico. The agency on Friday then confirmed that patrons of Olive Garden and Red Lobster restaurants in those two states were included in the illness clusters .

It’s frustrating from a Minnesota perspective to watch the investigation unfold just to the south. This state’s foodborne disease investigators have an international reputation for cracking outbreaks with speed and accuracy — salmonella cases involving peppers and peanut butter are two high-profile recent examples.

While state lines and other jurisdictional issues can create counterproductive barriers in investigations, the need to quickly trace the source of an outbreak means that everyone who works in public health is on the same team. As the cyclospora outbreak continues, this page hopes that federal officials and Iowa and Nebraska investigators will tap into Minnesota’s willingness to work with its neighbors.

In the months ahead, the cyclospora outbreak’s lead investigators also should take advantage of a Minnesota-made measure within the new federal Food Safety Modernization Act. Thanks to Sen. Amy Klobuchar’s work on this law, newly established regional food safety “centers of excellence” provide an unprecedented opportunity to retrospectively analyze outbreak investigations and to identify ways to improve in the future.

Minnesota has one of these centers, and lawmakers from across the Midwest should be pressing Iowa and Nebraska officials to use it. Food safety experts have long been urging this type of post-outbreak analysis, and the cyclospora outbreak is a compelling example of why this should be done. The important lessons learned would help the entire public health system respond more effectively — and potentially save lives — when the next foodborne outbreak occurs.