MadSci Network: Microbiology

Re: Why is eating raw pork bad?

Date: Wed Jun 16 06:15:30 1999
Posted By: Carl Custer, Staff, Office Public Health & Science, Scientific Research Oversight Staff , USDA FSIS OPHS
Area of science: Microbiology
ID: 928980519.Mi

Question: Why is eating raw pork bad?
I hear you always have to be super careful when handling raw pork. Why is it any worse than handling raw chicken or beef?
[Short answer: It's not!]
Why can people eat raw steak but you always hear they shouldn't eat raw pork?[They shouldn't eat raw steak - but see below for more than you probably wanted to know]

Nifty question whose answer will be based on history, urban legends, and science -- followed by THE FINAL WORDS.

1) History: Pork starts out with a bad reputation:
a) Pork is labeled as "unclean" in some religions.
b) Pork was one of the first foods with a scientifically identified foodborne pathogen. Over 150 years ago, trichina (Trichinella spiralis), a nematode, was identified as the cause of death of a woman in Germany (Trichinae is the plural of trichina, similar to "a cactus" or "two cacti").
c) Because trichinae were easily identified (the worms or their cysts are easily seen with 10-40 X magnification) public health officials passed laws to test pork and ban this pathogen. At the same time (1850 -1920) bacteria were also beginning to be recognized as food-borne pathogens but the identification methods were much more cumbersome. Thus, trichina became the most notable foodborne pathogen.

First USDA food safety regulations (about 20 years before Upton Sinclair's The Jungle) were for examination of pork for trichinae by microscope. This allowed U.S. pork to be exported to Europe.
USDA regulations for processing ready-to-eat pork to kill trichina predated similar ones for killing Salmonella in ready-to-eat beef by over 50 years.

2) Urban legends:
a) Trichina is the only hazard in raw pork: No, but, until very recently, processors only had to treat pork to kill trichinae. Some of the treatments also killed low levels of other pathogens, such as Salmonella, sometimes not. Now, processors have to treat ready-to-eat pork products to kill all infectious pathogens, including the more prevalent Salmonella.
b) Trichina is a deadly pathogen from pork: Well, yes and no. The disease (trichinosis) can be fatal but death is a rare occurrence -- even more rare from eating pork. In the past decade, more trichinosis cases have come from eating other meats such as bear meat, than pork.
See: trichino.htm
c) Trichina is the reason people shouldn't eat pork. No, trichinae are easy to kill by proper cooking - even easier to kill than Salmonella.
Good news: Trichinae cannot multiply outside of a host. Bad news: Salmonella can.

3) A little science:
Even free of trichina, raw pork is not always safe to eat raw; it contains other hazards. The infectious hazards include Salmonella, Campylobacter, Listeria monocytogenes and Yersinia enterocolitica.
In 1993, FSIS analyzed thousands of meat and poultry samples to establish a nationwide baseline of which bacteria are found on the meat carcasses and in some of the ground meat products.
following is a quick summary of the percent positive:

                   Pork:    Beef   Chicken   Ground beef   Ground Chicken
Salmonella:         8.7      1.0      20.0      7.5           44.6
Listeria monocyt.:  7.4      4.1      15.0     11.7           41.1
www.fsis.usda. gov/OPHS/baseline/contents.htm
Thus, beef looks safer than pork but ground beef looks about as bad as pork (FSIS didn't survey ground pork). Some have argued that the salmonellae in pork are generally not as infectious to humans as the salmonellae in beef.

Don't eat raw pork, don't eat raw beef, don't eat raw chicken -- unless they have been treated to inactivate the infectious pathogens that frequently occur on the raw meats.
For safe uncooked pork, try a slice of Genoa Salami, pepperoni, or prosciutto.
For safe uncooked beef, try a slice of Lebanon Bologna.
After handling raw meats, wash your hands thoroughly to remove any infectious bacteria. cuments/Handwash-FL99.html

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