The main reason – really, the only important one – for working to improve food safety is to reduce the incidence of food borne illnesses, hospitalizations, and deaths.
So it’s useful to get a handle on the scope of that challenge. The amount, kind and source of food borne illnesses helps us evaluate how much investment in food safety is justified. This is one of the key components of the analysis that underlies the current push to preventive risk management strategies.
Attribution of Food Borne Illnesses
A recent article cited in the Kansas State bites newsletter is must reading if you want to get a handle on this issue. The article is Attribution of Foodborne Illnesses, Hospitaliations, and Death to Food Commodities by using Outbreak Data, United States, 1998-2008, by John A Painter, et al, of the Center for Disease Control and Prevention. The authors developed a method to estimate the prevalence of foodborne illnesses for each of 17 food commodities using outbreak data reported by state and local health departments. In other words, the method summarizes and projects to the universe from a more limited set of data, but it is a solid overview of how food safety failures impact human health.
Some Eye-Catching Numbers
The food safety problem is as big as you think it is:
- About 9.6 million persons each year acquire a major food borne illness.
- During 1998-2008, 13,342 food disease outbreaks were reported, causing 271,974 illnesses. This data is part of the basis for projections.
- 46% of illnesses were caused by produce.
- More deaths were caused by poultry than any other product.
The authors organized an extensive dataset, and developed a method to analyze the approximately 9.6 million annual illnesses. Some of this data is reported in a series of tables available on the CDC website. The tables are in a technical appendix, and can be downloaded as PDFs.
Results: Product-Based Food Borne Illnesses
“More illnesses were attributed to leafy vegetables (22%) than any other commodity…” and caused 14% of hospitalizations and 6% of deaths. Leading causes of illnesses from leafy vegetables were norovirius and e.coli. Other produce also carried these infection sources, and also various strains of Salmonella were prominent.
The second largest source of outbreaks was the dairy commodity. It accounted for 14% of illnesses and 10% of deaths. Even though these products are typically pasteurized, infections occur due to improper pasteurization or due to contamination in handling after pasteurization (such as outbreaks of norovirus infections in cheese). Raw milk was a frequent source of Campylobacter infections, though the data is possibly skewed by reporting bias.
The largest source of deaths was poultry. The most common infection agents were Listeria and Salmonella, with a strong linkage between turkey processed meats and listeriosis between 1998 and 2002.
The authors note that the dataset is incomplete. For example, the reported outbreaks that form the basis of the research did not include incidents of Toxoplasma or Vibrio vulnificus even thogh these are known agents of food borne illness.
Food Safety Challenges Are in the American Diet
The most common sources of infection are found in foods that are most common in the American diet. While this is a truism, logically, it still indicates that the problem is widespread and cannot be attributed to unusual foods (like raw milk) that people rarely consume. We cannot ask people to avoid leaf vegetables and poultry when these are among the most common and useful parts of a healthy diet