The issue of freshness and nutritional quality in meats is less complicated than for vegetables and fruits. For meats, the major factors in production of animals affect mainly the palatability of the meat, not the meat's nutritional quality.
Milton meat market: Charles Erb, proprietor. 1913. Inside of Charles Erb's butcher shop in Milton, North Dakota. A counter with scale, meat carcasses hanging by hooks, and sausages are visible. The floor of the shop is covered in sand. Fred Hultstrand History in Pictures Collection, NDIRS-NDSU, Fargo.The Northern Great Plains, 1880-1920: Photograph from the Fred Hulstrand and F. A. Pazandak Photograph Collections. American Memory Collection. Library of Congress.
Charles Erb was born in Brooklyn, N.Y. in 1879 to German immigrants. He worked in a rope factory in Booklyn, later learning the butcher trade. He moved with his brother to Minnesota, and in 1901 he came to Willow City, N.D. from Pelican Rapids, Minn. In 1890 he had married Magdalene Damschen of Pelican Rapids. In Nov. 1908 he moved to Milton, N.D. and opened a butcher shop. They raised nine children. (Text accompanying photograph in collection.)
In the West, most consumers prefer not to each freshly slaughtered raw meat, whether muscles or organs. Most consumers also dislike cooked freshly slaughtered meat. These preferences have to do with the changes the animal undergoes upon death. (For my discussion, I am guided by Arnold Bender, "Meat and meat products in human nutrition in developing countries", Food and Agriculture Organization of the United Nations, Food and Nutrition Paper 53, Rome, 1992. See the Wikipedia article on rigor mortis. See also, Montana [State University?], "Meat Science 101", which is technical but accessible to the nonscientist.) At time of slaughter, the stunned animal is bled of blood. When it has died, in several minutes (in the case of beef steers), the carcass is split, and head, hide, and internal organs are removed. Shortly thereafter, the animal's muscles begin rigor mortis. Glycogen (a stored form of sugar) in the animals' muscles converts to lactic acid, forcing the muscles to contract.
If meat is cooked before rigor mortis or while still in rigor mortis, it is tough to chew and must be cooked longer to be fit for consumption (cooking can destroy nutrients; see below).
For meat to become tender naturally, enzyme changes must break down proteins in muscle fibers, rendering them palatable for consumption. The amount of time for complete rigor mortis of a slaughtered carcass depends upon the animal, the cut of meat, and at what temperature the rigor mortis occurs, among other factors. For beef steers, it takes seven to eleven days after slaughter, under chill conditions, for the enzymatic transformation of rigor mortis to finish, that is, to transform muscle into meat; this period is the aging period.
Meat must be consumed within several days after aging, before it begins to degenerate (spoil or decompose).
Slaughtered chickens hanging up by "painless killer". August 1941. Enterprise FSA (Farm Security Administration) canning and dressing station. Coffee County, Alabama. Photograph from the FSA-OWI, 1935-1945, American Memory Collection, Library of Congress.
Regarding meats, freshness therefore refers to consumption after aging. (See Arnold Bender, Meat and Meat Products ... [FAO] for details.)
Rigor Mortis (McWilliams, Meat, Fish, Poultry)
Animal | Onset in hours | Time to pass in hours
A British trade publication (Red Meat Industry Forum, Meat Quality) provides the following table of preferred aging periods:
Meat Aging, After Slaughter
Animal / Cut | Minimum aging in days | Preferred aging in days
Evaluation of practical importance of freshest local meats
"Freshness" is not a nutritional issue in meats in the same way it is with fruits and vegetables, but it does enter into meat nutritional quality. The longer the time before an aged meat is consumed, depending upon the temperature conditions of storage, then the greater the likelihood of protein degradation of the meat. That is to say, the amino acid chains are damaged (split) by the heat and become unavailable for digestion in the consumer's intestine. This damage also occurs if the meat is cooked at too high a temperature, so cooking methods of meat are an important factor in the nutritional quality of the meat when consumed.
Aside from this consideration, it is difficult for me to find any nutritional difference between local slaughter with aging in a local chill room and slaughter a thousand miles away with aging in a refrigerated truck during transport from that slaughter house to my local market.
----------
Other References
"This Is Life": A 30 minute educational film on the production of grassland meats (beef, pork, mutton) from ranch and farm, through processing, butchershop, and table. No feed lots. Grain finishing is portrayed and explained. Slaughtering at the slaughter house is not depicted, but meat cutting and packing by packers is shown. Film made in 1950s(?). From A/V Geeks at Internet Archive.
----------
Contents
Local Food
Revised, March 10, 2008. July 23, 2008.
Comments