One of the most important protections we have against foodborne illness is our disease-surveillance systems. These systems field reports from widespread sources and may include disease-reporting registries, local and state health departments, the Centers for Disease Control and Prevention (CDC), and utilize active outreach to clinicians and hospitals.
The data collected often reveal associations in time, place, person, and illness in the population. Such can lead an investigator to valuable information to stop outbreaks from continuing, but only if the data is accurate, properly understood, and acted upon.
Outbreaks usually have a defined course and chain of events, and when data are plotted, they will reveal onset dates, peaks and the tailing away of cases. The data may also reveal the immediate source of a contaminated food, allowing consumers to protect themselves if the information is made public. The epidemiologist is in a critical situation when they have data that supports a hypothesis that an outbreak of disease is occurring.
As surveillance improves, thanks to better diagnostics and more effective reporting, we now see a marked increase in foodborne illness outbreaks that come to light through an epidemiological approach.
Historically, the most fundamental finding in a foodborne outbreak investigation is the isolation of the causative organism from both victims and foods. When this detail is at hand, they provide strong associations between victims and likely causes. In such cases, the epidemiologist has traditionally made that information public. This allows the public to make a choice, helps in further case finding, and allows the removal of affected products.
But the gold standard is difficult to obtain, and only a fraction of the actual foodborne outbreaks known to occur have a confirmed cause; this success being dependent on the shelf life of the food items, the ability to isolate the pathogens from food, and other factors.
The Peanut Corporation of America (PCA) caused a deadly and long-lasting outbreak with its peanut butter products in 2007-2008. Cases continued over several weeks before the CDC — in tandem with Team Diarrhea — made the associations with King Nut, and eventually PCA. The question was repeatedly asked, “Why did it take so long for the outbreak to be recognized?” The delay drew the attention of some notables in epidemiology and led to criticism in CDC’s epidemiological approach.
On the other hand, recently a state health investigator pointed to a Salmonella outbreak in Cantaloupe without the causative agent being isolated. A detailed trace-back of cases led to strong associations between the importer and those made ill. The importer, who was named in the press, sued the epidemiologist, but later dropped the suit.
These shots across the bow of epidemiology are still apparently resounding.
Now we learn CDC and health departments in 10 states investigated an outbreak of 70 cases of Salmonella, but kept the process secret, and now will not reveal the name of the implicated restaurant. While it is clear that epidemiology as a science has limitations, the data can also be convincing, especially when there are clusters of cases that point to a common immediate source. Withholding the name of the immediate source, even when specific foods cannot be identified, does little to protect the public from immediate hazards or to find solutions to future occurrences.
While epidemiology is a powerful tool, it is one that can also backfire. In the international outbreak of E coli in sprouts last year, we saw the quandary epidemiologists faced. European officials jumped the gun several times. In good faith, they implicated a wide variety of possible vehicles and sources before finally identifying the source of contamination in a totally different country, and in a totally different product than was first thought (sprouts not cucumbers).
In the nationwide US outbreak of peppers/tomatoes in 2008, associations between tomatoes and cases became less and less likely as more cases of salmonellosis in persons eating peppers came to light. The effect on the tomato industry was dramatic, with losses in the untold millions.
When public health officials make mistakes in foodborne outbreaks, the industry suffers and the political fallout is extreme. To the extent that they do not act to protect the public, they fail their mission. We should not forget that local officials are closely tied to their communities in many ways. Local health departments rely on revenue generated from the local food service industry. After many years, bonds form between local public health agencies and industry, naturally, and out of necessity. When a regulator is compelled by the evidence and must take on the health protection role, he can find it painful. The wrong word — “strawberries instead of blueberries” can cost one their position. Therefore, it is not unreasonable for the regulator to be stuck in a “damned if you do, and damned if you don’t” situation, especially if he is a local.
In the end, honesty is the best policy during any outbreak of disease. When the investigator is guided by a careful analysis of data, an honest presentation of the facts and truthful explanation is all we can ask for. Consumers demand no less from CDC. Perhaps there needs to be “whistleblower protections” for CDC from lawsuits (ironically, this protection is afforded now by the FSMA-but only to workers in FDA-regulated facilities).
It’s in the best interest of everyone to work together in crisis times like these in food safety. The public understands and forgives a mistake when it occurs out an abundance of caution to protect them, but there is no forgiveness for a failure to inform them and they suffer as a result. The failure of CDC to name names is preventing the redress that victims rightfully have for damages and also reflects the power industry has to keep our investigators silent.
Roy Costa is the founder and owner of the consulting firm Environ Health Associates, Inc. Mr. Costa is a registered professional sanitarian with 30 years of environmental heath practice in the academic, government and private sectors. Mr. Costa is an educator and food safety trainer with International experience in a number of countries.