I’ve lived in rural America most of my life, and listened to – well, heard, anyway – “the farm report” on the radio more often than I ever wanted. I have heard the term “pork belly” many, many times, and even, y’know, could picture a pork belly. But what I didn’t know is that belly is the part of the pig that makes bacon (of the American type, at least). I know where various cuts of meat come from. I got that ham is the leg, and loin is, well, the loin. But I’d just never considered where bacon would start its life. Now I know why those pig bellies mattered so much to the ag reporter – in my estimation, bacon is the best part of a pig.
Back in the mists of time before refrigeration, the “ancients” (whoever they are) practiced curing as a way to preserve food for the long haul. Salt, often used with drying and smoking, was found to be a great help in preserving food. The Chinese were using salt to preserve food in about the13th century B.C. In Homer’s time (850 B.C.) the Greeks used salt with natural impurities, called nitrites. Nitrites are what give ham and bacon their lovely red color. Turns out nitrites are also the best way to keep botulism away – hence, they are still used today.
Salting has a couple of effects on meat. First, almost all meat contains a pretty high percentage of water, which must be removed to prevent spoiling. Applying salt will extract much of the water. The salt also permeates the meat and creates an environment that makes it difficult for bacteria to survive.
One of the ways salting helps preserve food is by affecting the process of osmosis. Osmosis is the movement of liquid through a semipermeable membrane, such as a cell wall – it’s the way tree roots get water out of the ground. To see osmosis in action, add a couple of tablespoons of salt to a cup of water, then add a potato slice. The water from the potato will move into the saltwater, and the potato will shrink and become less stiff.
This kind of water-removal environment is unfriendly to bacteria. While bacteria have different resistance levels, salt concentrations as low as 3 percent will kill Salmonella.
Curing takes time because the salt has to permeate the meat, and it must be done at carefully controlled temperatures (below 40 degrees, but above freezing). For the last step, the bacon is smoked, which adds more flavor and reduces mold and bacterial growth.
Salt alone doesn’t make for a tasty treat, so curing mixes often include additional items.
• Sugar or some other sweetener (like maple syrup or honey) adds flavor and acts as food for some good bacteria that tenderize the meat.
• The “impurity” used by Homer’s cooks, sodium nitrate or sodium nitrite (also called saltpeter), preserves and makes the meat red (meat treated with just salt doesn’t look very appetizing).
• A spice mix that is special for each maker. This is where people get creative. Peppers of various kinds, allspice, cloves (also astringent), cinnamon, garlic, sage, the list goes on.
Bacon, salt pork and ham (and a few snazzier products such as guanciale, which is made from a pig’s jowl, seriously) are basically vestigial meat products, created in a time before refrigeration. The only salted beef product that still gets any play is corned beef (they called little salt chunks “corns”), and salted mutton is pretty much completely out of style. You can still find some cured fish products – but only die-hard Scandinavians really go for them. Cured pork products are still around, however – because they taste great!
