Food-borne Outbreaks Caused By Ingredients: Would You Like Some Pepper With That?

I often discuss the globalization and complexity of our food supply to highlight both the wonderful diversity of our yummy foodstuffs but also the challenges from contamination. Recently, architectural students in California provided a vivid example when they deconstructed a taco from a street-vendor to see the origin of each of the ingredients (see article) — from local cheeses to international spices and rice, which collectively travelled 64,000 miles to Juan’s Taco Truck in the San Francisco’s Mission District. State and federal public health officials do the same thing whenever there is a food-borne outbreak — identify the likely suspect and trace it back to its source — whether it be the grocery store, food distributor, factory, slaughterhouse, or farm. This is easier with what are called commodity outbreaks: ground beef or spinach, for example. Tracking down the source is extremely difficult, however, when the contamination is an ingredient that may be in many different foods.

The recent outbreak of Salmonella Montevideo is a great example of this complexity (see CDC investigation update). The outbreak started last summer (2009) and thus far has affected 252 people in 44 states and the District of Columbia. An epidemiologic study found salami packaged by Daniele International, Inc., to be the most likely food vehicle. Laboratory testing by the Rhode Island Department of Public Health and by the Food and Drug Administration (FDA) found that the black and red crushed pepper used on the meat was contaminated with the same Salmonella as the outbreak strain. These ingredients were traced back to two companies — Wholesome Spice in New York (red pepper) and Mincing Overseas Spice in New Jersey (black pepper). Recalls of contaminated products are under way.

New Tools for Investigations

One of the new key tools used in the Montevideo outbreak investigation was the use of shoppers’ cards from ill individuals. With permission from the ill patients and in conjunction with local public health authorities, Casey Barton Behravesh and her state health department colleagues in the investigation were able to view which common products were purchased. While the case-control study helped determine that salami was probably the food vehicle, it was the information from the shoppers’ cards that pointed to the specific brand consumed by each of the ill patients. CDC provided purchase information from consumers’ shopper cards to the Food Safety and Inspection Service (FSIS). This allowed FSIS to determine lot information for salami products that had been purchased by people before they got sick. In addition, FSIS was able to identify multiple lots of pepper that were used during the production of those salami lots. This information was shared with FDA, which traced pepper lots and investigated spice suppliers.

More recently, Salmonella Tennessee has been detected in the commonly used flavor enhancer, hydrolyzed vegetable protein (HVP), made by Basic Food Flavors in Nevada (see FDA press release), and this has led to the recall of hundreds of products. A customer of Basic Food Flavors found Salmonella Tennessee during routine product testing and notified FDA officials, who investigated the facility and found the same Salmonella strain in the processing environment. Purchasers of bulk HVP products from this company have been encouraged to recall and either destroy the goods they have or recondition them (using procedures to kill Salmonella) so that the food is safe to eat. Fortunately, this strain was detected before people became ill.

Lessons Learned

So what do we learn from this? We learn that as the food production and delivery systems become more complex, we also need our food safety systems to similarly evolve. This translates into new tools — such as shoppers’ cards — in combination with the current testing and investigation practices we use to protect public health. By combining these strategies, we can do the best possible job of ensuring the safety of our nation’s food supply.