June 06, 2011

Frightening food

Arvid vs the CakeFood scares are in the air (in the pot?) right now, but what should we be rationally worried about in terms of outbreaks of food-borne diseases?

CDC has a Foodborne Outbreak Online Database that contains cases from the last two decades. These are cases serious enough that somebody reported them to the CDC. They cover everything from bad sausages to salt and muktuk (fermented beaver tail). Writing a parser for the data in Matlab, I got the following results:

Most number of people affected by the food (i.e. what is most likely to get you if you eat an average diet):

Affected# outbreaksMean sizeFood
56769195229.082480 -
27605550.181818multiple foods
228517134.411765tomato, unspecified
17473582.333333other milk, pasteurized
15361790.352941salsa, unspecified
153511535.000000peppers, jalapeno; tomato, unspecified; peppers, serrano
13322847.571429potato salad
12733239.781250pork, BBQ
10161953.473684cake, unspecified

Many outbreaks are never traced, or due to multiple foods. But otherwise it is clear that it is the veggies that are risky, besides the somewhat obvious milk and BBQ pork. Badly washed vegetables or spicy salsas that hide off tastes are clearly worth watching out for. And while the cake might not be a lie, it can be slightly risky.

What foods cause the most alarms? These would be the foods that are easy to get illness from, but the outbreaks are small:

Affected# outbreaksMean sizeFood
210563.750000fish, mahi mahi
27605550.181818multiple foods
210494.285714fish, ahi
9404122.926829oysters, raw
9344023.350000lettuce-based salads unspecified
219395.615385tuna, unspecified
320368.888889ground beef, hamburger
9363526.742857ground beef, unspecified
5483316.606061chicken, unspecified

Now seafood and meats jump up, although those salads still cause trouble. The reason for the mahi-mahi is likely ciguatera - those dinoflagellates can produce some pretty impressive poisons.

What foods produce the biggest outbreaks?

Affected# outbreaksMean sizeFood
153511535.000000peppers, jalapeno; tomato, unspecified; peppers, serrano
9501950.000000gravy, beef; roast beef, unspecified; potato, mashed
7161716.000000Peanut Butter; Peanut Paste
7151715.000000peanut butter
17473582.333333other milk, pasteurized
5521552.000000tuna salad; salad bar
5171517.000000chicken, baked; green pea salad
9272463.500000corn, unspecified
3331333.000000pasta salad; potato salad; vegetable-based salads unspecified


The problem here is that many of these are single outbreaks - that pepper outbreak affected 1535 people. So to be on the safe side, lets look at the biggest average size of outbreaks where there has been more than 2:

Affected# outbreaksMean sizeFood
17473582.333333other milk, pasteurized
9994249.750000macaroni salad; potato salad
6503216.666667roma tomato
9935198.600000green onion/scallion
6754168.750000basil, unspecified
6534163.250000orange juice, unpasteurized
4133137.666667pot pie
228517134.411765tomato, unspecified

The vegetables strike again. This is also where biosecurity has to work hardest: presumably these are the easiest ways of distributing food-borne pathogens. The dairy industry is recognized, but how much protection does our watermelons have? (the problem with watermelons and several of the others is likely that they have an often unwashed surface that people touch with while eating, and then they get the pathogens in their mouths)

In total, 161284 people were affected in 5153 outbreaks. 181 died, 7803 were hospitalized.

And people worry about genetically modified food! They should worry far more about ordinary dirt and the natural, very organic pathogens that live there.

(Some caveats: the same foodstuff might occur in several food descriptions, making exact analysis a bit tougher than what I want to do a Monday evening. I make no claims to know what I am doing. Here is the processed file, sorted by affected people: Download file )

Posted by Anders3 at June 6, 2011 09:16 PM