A public health outbreak is the occurrence of disease cases in excess of normal expectancy. Disease outbreaks are caused either by infectious agents, such as bacteria, viruses, fungi, parasites, and noxious agents, such as chemicals and toxins. As a consequence, an outbreak investigator is faced with the formidable task of solving the true cause of the outbreak not only with the time pressure of appropriately treating the victims, but also the prevention of spread in the community and beyond. Perhaps the initial key is knowing if the agent is spread via the inhalation, dermal absorption, or ingestion. This is not always clear, as exposure can be through multiple pathways.
The difficulty and uncertainty in the investigation of disease outbreaks of unknown cause illustrates the importance of how food should be considered as a possible route to transmission until it is effectively ruled out based on evidence. The U.S. Centers of Disease Control and Prevention has stated that researchers have identified more than 250 foodborne infectious agents.1 The number of possible noxious chemical agents is much higher because, in principle according to Paracelsus, “All things are poison, and nothing is without poison; the dosage alone makes it so a thing is not a poison."2 Besides the thousands of chemicals approved for use in food, such as food additives, pesticides, and veterinary drugs, many naturally occurring toxins, like heavy metals and mycotoxins, can pose a risk to health. The present paper describes an outbreak that was ultimately determined to be foodborne and the need for explicitly considering this possibility in any investigation.