Misconceptions about pork (volume 1, chapter 3)
The "safe" temperature for cooking pork is one of the most misunderstood - and distorted - aspects of food safety. Numerous so-called authorities or experts recommend massively overcooking pork. Why pork? The usual reason given is the danger of contamination with the roundworm Trichinella spiralis.
This assertion is misleading for several reasons, as discussed below. Most importantly, improvements in pork farming and processing practices have virtually eliminated Trichinella contamination in commercially produced pork in developed countries. One study showed that only eight cases of trichinellosis (also called trichinosis) could be attributed to pork grown commercially in the United States between 1997 and 2001. During that same period, the American population consumed about 32 billion kg / 70 billion 1b of pork. That's an awful lot of pork to generate only eight cases of trichinellosis.
Trichinellosis from wild game (mostly bear meat) and from non-commercially raised pork was also very rare: just 64 cases over five years, for a total from all sources of 72 cases. This is such a low incidence for a country of more than 300 million people that trichinellosis ranks among some of the rarest diseases known to medicine. When it does occur, the disease is neither fatal nor serious, and is easily treatable. It is hard to see what all the fuss is about; there are far more common and more serious public health threats than trichinellosis.
The alarmism also ignores two other points. First, most commercial pork is frozen to kill the parasite. Second, and perhaps more surprising, Trichinella is very easy to kill with a low heat.
The FDA cooking regulations for eliminating Trichinella include temperatures as low as 49C / 120F, albeit maintained for 21 hours. (The main reason to cook at temperature that low is to process ham in the style of a "raw" ham). The regulations do not even bother to list temperatures higher than 62C / 144F because the time required to eliminate the parasite would be less than a second.
The FDA 2009 Food Code makes no special recommendations at all for cooking pork. Instead it suggests using the FDA's time-and-temperature table for whole-meat roasts for all meats.
Other pathogens that can infect pigs, such as Salmonella, are not unique to pork - another reason why the FDA Food Code does not require a different standard for it. The cooking recommendations in the FDA time-and-temperature table will destroy Salmonella to the 6.5D level in any meat, including pork. Yet most information sources for consumers, including the USDA website and the National Pork Board, recommend a cooking temperature of 71C / 160F, which is laughably high. Dry, overcooked pork is the inevitable result, particularly when leaner cuts are cooked at this temperature.
Why does this mistake persist? Exaggerated concern about Trichinella is clearly one factor. So is the failed strategy of relying on temperature only. A desire to maintain the status quo may also play a role; once you've taught people that pork needs to be overcooked, it takes some courage to change course, particularly if it means admitting you've made a mistake.
In the authors' experience, convincing chefs that pork has no special cooking requirements compared with those for beef or other meat can be a difficult feat. Showing them the FDA Food Code provokes statements such as, "But that must be wrong!" Cookbook authors have less of an excuse for perpetuating this travesty. Many have repeated the silly claims about 71C / 160F for years without bothering to check technical sources to verify the facts.
Parasitic worms (volume 1, p120)
Fear of Trichinella spiralis, perhaps the most infamous foodborne worm, has inspired countless overcooked pork roasts. The trichina is widely dreaded for its ability to burrow into the muscles of pigs and other livestock, inflicting people who eat the contaminated meat with the disease trichinelllosis (also called trichinosis). Most of us learned of the danger from our mothers as well as from some public health authorities and nearly all cookbook authors, who have insisted for years that pork should always be cooked well done.
Yet in reality the Trichinella roundworm has little impact on either the number or severity of foodborne disease cases in the United States. A CDC surveillance report that covers the years 1997-2001 confirms that physicians have seen case loads associated with eating pork plummet: of 55 cases in which people developed symptoms of trichinellosis, investigators could link only eight to commercial pork products purchased in the US. Most of the few dozen other cases resulted from eating the meat of wild game - bears in particular, but also boars and mountain lions - or pork obtained directly from farms or home raised pigs, to which industry standards and regulations do not apply.
Although concern about foodborne worms can be overblown, no-one wants to harbour parasites that can stick around for years or even decades. So all cooks should know some basic facts about the parasitic roundworms, flukes, and tapeworms that sometimes make their way into the food supply.
The diversity of these organisms is underappreciated. Beyond Trichinella and other roundworms or nematodes, foodborne worms of note include flukes (trematodes) and tapeworms (cestodes) these parasites produce disease through two main mechanisms: the worms either penetrate body tissue during invasive infections, or the live in the gut as non-invasive infections.
Roundworms (volume 1, p120)
In the kitchen killing trichinae does not require the excessive heat that most people imagine. the FDA Food Code recommends using the same time-and-temperature combinations for cooking pork as it does for beef or lamb (for example, 54.4 degrees C / 140 F for 112 minutes or 60 C / 140 F for 12 minutes ). US Government regulations for killing trichinae specify even lower values: 54.4 C / 130 F for 30 minutes or 60 C / 140 F for one minute.
So why did Mom think she had to cremate the pork roast? Well-meaning public health authorities have long exaggerated both the threat of trichinellosis and the cooking temperature needed to prevent it. Such overstatement may have arisen from good intentions, but at some point misleading recommendations become irresponsible.
Freezing also kills trichinae in pork. For this reason, virtually all pork and pork products sold in the US have been frozen even if they are labelled "fresh" at the store.
• This is an edited extract from Modernist Cuisine: The Art and Science of Cooking (Taschen, £400)
