21 November 2001

The Emerald Steak: What affects the eating experience?

Many factors influence the quality of the meat you take home from the store or order at a restaurant. The more you know about a cut of meat, the better prepared you can be to enjoy the experience.

Fat Content

Most consumers probably recognize the quality grades “select” and “choice.” They deal primarily with fat marbling and to a lesser degree with the animal's age. Grocery shoppers prefer meat with leaner marbling and less external fat, but many Americans still regard the flavor of corn-fed beef as the benchmark for quality.1

A small amount of fat functions as a beneficial cooking “cushion,” facilitating heat conduction and allowing the center of the cut to reach a greater degree of doneness before the outer surface becomes too tough. That is why cooking time needs to be adjusted when cooking really lean beef. Leaner meat requires 1/3 less time to cook.

Management and genetics also influence how meat grades, but we'll discuss those factors more when we get into beef's nutritional value.

Marbling, age, stress, genetics, synthetic growth implants, and processing all influence tenderness, but contrary to what some assume, marbling only has a 10% effect on actual tenderness (genetics had a 30% correlation).3

Some breeders apply genetic selection for tenderness, and both to cut costs and to ensure tenderness, ranchers try to raise animals that will gain enough weight and be ready for harvest while still young and growing. The younger the animal, the more tender the meat.

One can hardly overemphasize the value of reducing animal stress, particularly at harvest. When an animal experiences stress just prior to harvest, the adrenaline released causes muscle fibers to shorten, and this shortening makes for tougher steaks. Intense excitement can also deplete muscle glycogen content resulting in a higher final muscle pH, causing undesirable color and conditions favorable to increased microbial growth.4

Selecting docile breeding animals, designing efficient facilities, and training quiet handlers pay huge dividends. In addition, many conscientious ranchers practice dehorning (genetic or mechanical) and removal of protrusions from handling facilities in order to avoid injuring animals.

A taste panel gave synthetic-growth-hormone-free beef an edge for tenderness5 even though the difference in hormone levels appears very minute (1.9 nanograms and 1.3 nanograms for 3-ounce servings from implanted and nonimplanted steers respectively).6 Implants may also increased the total level of cholesterol in beef.7

Most beef undergoes aging (a time allowing for the natural break-down of the meat’s tougher connective tissue). Meat processors also have mechanical and chemical means to ensure the tenderness of the food they prepare. Mechanical tenderization may include shockwaves traveling through water to submerged meat or a bank of needles passed through boneless cuts. Enzymatic tenderization involves applying plant-derived, collagen-degrading enzymes to break down the tougher connective fibers in the muscle. These enzymes are taken from the papaya, pineapple, or fig.8

Food Safety
The USDA and state departments of agriculture carefully monitor meat harvesting and processing. Local health districts look after storage and preparation. The USDA requires tax funded, federal inspection at slaughter for any meat destined for resale. Custom butchering (the processing of a person’s own animal for personal consumption) is the only exception.

Because bacterial contamination causes most illnesses associated with beef, government agencies and industry leaders have placed increased emphasis on science-based approaches to control the problem. The Food Safety Inspection Service requires certain sanitation procedures (including regular thorough cleaning). These measures often integrate into standard operating procedures that also contain product consistency safeguards.9

With complete sterilization practically impossible, sanitation activities seek to create multiple obstacles through which all pathogens would have to pass before contaminating food (called critical control points). The facility must devise a Hazard Analysis and Critical Control Point (HACCP) plan, and violations in these areas carry heavy consequences.

Thus, processors prevent most disease causing “bugs” from entering the food supply by concentrating on the biggest problems first. The HACCP principles include (1) analyzing potential hazards, (2) determining those points requiring action to maintain product integrity, (3) establishing parameters for monitoring, (4) setting monitoring methods, (5) outlining corrective measures, (6) establishing record keeping, and (7) developing systematic verification patterns to track the plan in action.10

The application of these principles takes many forms. Washing beef carcasses immediately after skinning prevents bacteria colonies from attaching to the meat. Steam pasteurization and rinsing with special solutions has apparently reduced the need for irradiation in some trials.11,12,13 In the storage and preparation stages, temperature is essential. The shorter time meat spends between 28° and 150°F the longer the shelf life and the lower the risk of food-borne disease. Food workers must also eliminate possible cross-contamination between cooked and uncooked food.

Use of antibiotics in food animals may cause direct allergic reactions14 and contribute to populations of drug resistant pathogens, including those responsible for food-borne disease. 15,16,17

Feeding antibiotics for growth promotion and disease prevention (vs. treatment) raise concerns similar to those discussed for the habitual use of antibiotics in humans. A growing number of ranchers avoid using antibiotics altogether in order to offer their customers a clear option. Government and industry are both working to reduce residue levels in food.

Evidence indicates anything that increased the acidity of a cow’s digestive system also increased the risk of Escherichia coli infection in people consuming beef. Pathogenic E-coli require relatively acidic conditions to proliferate and survive exposure to human stomach acid. Since a high grain ration tends to increase the acidity of an animal's digestive tract, some have suggested feeding a high grain ration may contribute to increased risk of E-coli contamination. 18,19 But in any case, the actual percentage of infected cattle remains very small.

Mad Cow Disease
Due to the apparent transmissibility of mad cow disease (Bovine Spongiform Encephalopathy), regulators suspended the use of meat and bone meal in animal feed and took other aggressive steps to prevent the disease

Many unanswered questions remain, however, about the extent of the disease’s transmissibility and the width of possible exposure for both humans and animals. Answers come slowly because of the long incubation period and the current diagnostic limitations (post mortem examination being the only conclusive method).20

1“Consumer Willingness-to-Pay for Flavor in Beef Steaks: An Experimental Economic Approach,” From Cornhusker Economics, in the Stockman Grassfarmer, August 2001: 33.
2“Illustrations of Beef Marbling,” in John R. Romans et al., The Meat We Eat, 14th ed. (Interstate Publishers Inc., Danville, Illinois, 2001) Color Pictures.
3Ben Hardin, “Predicting Tenderness in Beefsteaks,” Agricultural Research, November 1999, in Robinson 55.
4John R. Romans et al., The Meat We Eat, 14th ed. (Interstate Publishers Inc., Danville, Illinois, 2001) 902.
5National Cattlemen’s Beef Association, “Beef’s Nutrient Bundle,” Cattle and Beef Handbook, (National Cattlemen’s Beef Association, Englewood, CO, Sixth printing June 1999) p. A-3. B-7.
6Chuck Rightmire, “Study Says Consumers Can Identify Implanted Beef,” Western Livestock Reporter, 1 September 1999: 1 & 9.
7S. K. Duckett et al., “Effect of Anabolic Implants on Beef Intramuscular Lipid Content,” Journal of Animal Science, Vol. 75, No. 5, May 1999: 1100-1104.
8Romans 670 and 672.
9Romans 50.
10Romans 59-63.
11A. L. Nutsch et al., “Steam pasteurization of commercially slaughtered beef carcases: evaluation of bacterial populations at five anatomical locations,” Journal of Food Protection, Vol. 61, 1998: 571, in Romans 20.
12Prasai, R. K., et al., “Microbiological Effects of Acid Decontamination of Beef Carcasses at Various Locations in Processing,” J. Food Prot., Vol. 54, 1991: 868 in Romans 23.
13Joseph Weber, “Keeping the Bugs Off Beef,” Business Week, 6 March 2000: 52.
14M. I. Oklo, “Bacterial Drug Resistance in Meat Animals: A Review,” Int. J. Zoonoses, Vol. 13, No. 3, September 1986: 143-152.
15M. Teuber et al., “Veterinary Use and Antibiotic Resistance,” Curr. Opin. Microbiology, Vol. 4, No. 5, October 2001: 493-499.
16S. D. Holmberg, “Drug Resistant Salmonella from Animals Fed Antibiotics,” New England Journal of Medicine, Vol. 311, 1987: 617-622.
17J. S. Spika et al., “Chloramphenicol-resistant Salmonella newport traced through hamburger to dairy farms,” New England Journal of Medicine, Vol. 316, 1987: 565-580.
18F. Diez-Gonzalez et al., “Grain Feeding and the Dissemination of Acid-Resistant Escherichia coli from Cattle,” Science, Vol. 281, 1998: 1666.
19D. E. Herriott, “Association of Herd Management Factors with Colonization of Dairy Cattle by Shiga Toxin-Positive Escherichia coli O157,” Journal of Food Protection, Vol. 61, No. 7, July 1998: 802-807.
20Mary H. Cooper, “Mad Cow Disease,” CQ Researcher, Vol. 11, No. 8, 2 March 2001: 162-179.

No comments:

Post a Comment