A Nationwide Audit of the Composition of Pork and Chicken Cuts at Retail

JOURNAL OF FOOD COMPOSITION AND ANALYSIS ARTICLE NO.

11, 249 –261 (1998)

FC980586

A Nationwide Audit of the Composition of Pork and Chicken Cuts at Retail D. R. Buege,*,1 B. H. Ingham,* D. W. Henderson,† S. H. Watters,† L. L. Borchert,* P. M. Crump,* and E. J. Hentges‡ *University of Wisconsin at Madison, Madison, Wisconsin 53706, U.S.A.; †University of Wisconsin at River Falls, River Falls, Wisconsin 54022, U.S.A.; and ‡National Pork Producers Council, Des Moines, Iowa, U.S.A. Received October 1, 1997, and in revised form May 26, 1998 A 1996 nationwide market basket audit of the physical composition and nutrient content of eight pork cuts and four chicken cuts was conducted to determine if differences exist between current cuts and pork cuts of 1989 (USDA Handbook 8-10) or chicken cuts of 1979 (USDA Handbook 8-5). Pork and chicken cuts were purchased from supermarket chains in five United States cities. External fat thickness was measured on pork cuts, and pork and chicken cuts were separated into lean, bone, fat, connective tissue, and skin. Lean, fat, and skin were composited by cut and city and analyzed for fat, protein, cholesterol, and fatty acids. Mean external fat thickness across all pork cuts decreased significantly (P , 0.01) from 1989, from 2.3 to 1.4 mm. Mean percentage of lean from pork cuts increased (P , 0.01), from 75 to 81%. Mean fat and cholesterol contents of lean from 1996 pork cuts were unchanged from 1989 levels (4.8% vs 5.2%; and 62 mg/100 g vs 59 mg/100 g, respectively). Mean yield of lean from bone-in, skin-on chicken cuts was unchanged from 1979. Mean fat content of lean across all chicken cuts increased (P , 0.01) from 3.0 g/100 g in 1979 to 3.9 g/100 g in 1996. Mean cholesterol content of lean from chicken cuts averaged 84 mg/100 g (1996) compared to 69 mg/100 g (1979), differences not significant. Pork fat was composed of 38% saturated/53% unsaturated fatty acids, and chicken fat contained 29% saturated/61% unsaturated fatty acids. © 1998 Academic Press

INTRODUCTION The purchase decisions of many consumers are influenced by the nutrient content of available foods. Trend information published by the Food Marketing Institute in 1996 (FMI, 1996) reported that nearly two out of three shoppers are concerned about the fat content of their diet, and one in four is concerned about cholesterol levels in foods. Although pork and other meats provide significant amounts of many valuable nutrients to the human diet, they also are a source of fat and cholesterol. Since the composition of animal products can change due to alterations in production practices, meat processing procedures, and merchandising techniques, it is important that the composition of such products be periodically monitored to ensure that consumers are provided with accurate nutrient information about these products. During the past 50 years pork producers have reduced the amount of waste fat on pigs, and closer fat trimming procedures by processors and retailers have likewise contributed to creating lower fat pork products. A nationwide market basket survey of fresh pork products conducted in 1989 (Buege et al., 1990) found cuts to be more closely trimmed 1 To whom reprint requests should be addressed at Muscle Biology Laboratory, 1805 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706. Fax: (608) 265-3110.

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0889-1575/98 $25.00 Copyright © 1998 by Academic Press All rights of reproduction in any form reserved.

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of outside fat and significantly lower in fat than reported in USDA Handbook 8-10 (Pork Products: Raw, Processed, Prepared) (Anderson, 1983). Results of the 1989 study were used to update the composition of pork cuts in that Handbook in 1992 (Anderson, 1992). Chicken is an alternative choice to pork and other meat products for shoppers’ food dollars and in the minds of some consumers is perceived as lower in fat and cholesterol (FMI, 1996). The composition of chicken products as presented in USDA Handbook 8-5 (Poultry Products: Raw, Processed, Prepared) (Posati, 1979) has not been updated since 1979. Collecting pork cuts at retail stores nationwide afforded the opportunity to likewise sample chicken cuts at the same time, to determine their current composition. Therefore, the objectives of this project were (1) to determine if changes have occurred in the physical and nutrient composition of selected fresh pork cuts in retail markets since the 1989 Market Basket Study, and (2) to determine the composition of selected chicken cuts in retail markets, and to compare those findings to information in USDA Handbook 8-5. MATERIALS AND METHODS Sampling Procedures Designated pork and chicken cuts were sampled from self-service retail meat cases in five United States cities in June and July 1996. Cities chosen represented major metropolitan areas in different geographical regions of the United States, and included New York, Atlanta, Chicago, Dallas, and Los Angeles. Collectively, these cities comprise approximately 20% of the total United States population (Trade Dimensions, 1995), and each was included in the 1989 Market Basket Study of pork composition (Buege et al., 1990). Four stores were randomly selected to be sampled in each city, representing the leading retail supermarket chains in the metropolitan area. The number of chains sampled per city was determined by the relative size of each chain’s market share. Two chains were involved in the Chicago sampling, while all other cities had four chains represented. Combined market shares of the chains sampled in each city ranged from 48 to 61% of total grocery sales within each metropolitan area (Trade Dimensions, 1995). Table 1 lists the eight pork loin cuts and four chicken cuts sampled in this audit. Ground pork and ground chicken were also collected. One package of each of the pork and chicken products was selected from self-service retail cases using a random number system. Sampled products were placed into plastic bags, packed in wet ice in insulated coolers, and shipped via an overnight express delivery service to the Meat Science Laboratory at the University of Wisconsin-River Falls. In some cases not every target cut was available in sampled stores. Sample Handling and Preparation External fat trim was determined on pork cuts by measuring external fat at three to six sites per cut, following the protocol of the 1989 Market Basket Study (Buege et al., 1990). All cuts within a package were designated as part of a single sample, and a mean external fat thickness was determined for each package. Mean external fat thickness for each pork cut within a city was calculated from individual package means. Pork cuts were carefully separated into lean, external fat, seam fat, connective tissue, and bone. Chicken cuts were separated into lean, separable fat, connective tissue, bone, skin, and wing tips. Wing tips are the last joint of the chicken wing and consist almost entirely of bone, cartilage, and skin. No effort was made to recapture the free moisture

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TABLE 1 Pork and Chicken Cuts Sampled in 1996 Audit

which migrated from the cuts into the package during retail display and transport, since this loss likewise occurs in normal consumer handling of these products. Component parts were weighed and their percentages computed on a total package basis. Mean physical composition for each cut within a city was calculated from individual package results. Lean from each cut, separable fat, and skin were individually composited on a city basis. To assure homogeneity of the separable lean from each package, lean tissue collected from a package was cut into 1.2- to 2.5-cm cubes, thoroughly blended by hand, and then representatively sampled for the proper quantity to be contributed to the city composite. This predetermined quantity of lean from each retail package was placed in an individual plastic bag, vacuum-packaged, and stored at 2°C until shipment in wet ice via an overnight express delivery service to Covance Laboratories in Madison, Wisconsin, for determination of protein, fat, cholesterol, and fatty acid composition. The final physical homogenization of lean composites for each cut was accomplished at the analytical laboratory by combining, grinding, and mixing the appropriate individual package samples, prior to chemical analysis. Separated pork fat, chicken fat, and skin from all products within a city were individually combined, blended to achieve homogeneity, and then representatively sampled to provide city composites for each type of tissue. Extra care was used to assure the capture of any residual fat and moisture which may have been released from the tissues into sample bags. Because the number of retail chains sampled within a city was based upon relative market shares of its leading chains, city means for external fat thickness and physical composition and city analytical results for lean, fat, and skin were thereby weighted for chain market share within the city. Since the packages collected reflected the chain market

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shares, equal amounts of lean, fat, or skin were contributed from each package in forming the respective city composites for chemical analyses. Protein, Fat, Cholesterol, and Fatty Acid Content City composite samples of lean, fat, and skin were analyzed for nutrient composition. Sample composition was determined according to the following standard methods: protein (Kjeldahl nitrogen 3 6.25; AOAC 955.04C and 979.09); fat (chloroform z methanol extraction; AOAC 983.23); and cholesterol (as trimethylsilylethers; AOAC 976.26). A known amount of 5a-cholestane was added to cholesterol samples during extraction as an internal standard. Analysis of cholesterol was performed on a HP 5890 Series II gas chromatograph using an Ultra 2 column (25 m 3 0.32 mm id 3 0.17-mm film; Hewlett Packard) with flame ionization detector (FID). The carrier gas was He, at 2.0 ml/min with a split ratio of 12:1 and temperature programming to elute cholesterol: injector 250°C; detector 300°C; column 190°C for 2 min, 20°C/min to 230°C, hold 3 min; 1°C/min to 245°C, and 5°C/min to 295°C. Portions of the total fat extracted from fat and skin composites were used for fatty acid analysis after derivitization to the appropriate methyl esters (AOCS, 1981). Methyl esters of fatty acids having 8 to 22 carbon atoms were separated on a HP 5890 Series II GC with DB-Wax column (30 m 3 0.53 mm id 3 1.0-mm film; Hewlett Packard) and FID detector. Carrier gas was He, 1.0 ml/min with a split flow ratio of 8:1. Temperature programming to elute fatty acid methyl esters was as follows: injector 250°C; detector 300°C; column 120°C for 2 min; 10°C/min to 150°C; 3.5°C/min to 210°C with a 13 min hold at 210°C. The fatty acid methyl esters were quantitated using external standards. Energy values were derived by multiplying the amounts of protein and total fat by factors 4.27 and 9.02 (kcal), respectively, assuming a negligible amount of carbohydrate in each product. At the start of this study Covance Laboratories conducted homogeneity studies on composited samples to verify that blending was adequate to provide representative results from a single analytical subsample. Results of five replicate subsamples from a lean composite of boneless loin roasts gave a coefficient of variation (CV) of 3.7% for total fat, on a mean fat level of 6.1%. Five replicated subsamples of lean from composited chicken thigh yielded a CV of 1.4% for cholesterol, on a mean cholesterol level of 99 mg/100 g. Five replicated subsamples from a pork fat composite produced CV’s of 0.5% or less for the five fatty acids present at levels greater than 1.5 g/100 g. In addition to internal and external standards required for analyses, Covance Laboratories routinely runs in-house quality control materials with each batch of samples to verify analytical accuracy and precision. In-house controls are validated against Standard Reference Material from the National Institute of Standards and Technology wherever such are available. Results from 110 analyses of a standard waffle material for cholesterol yielded a CV of 4.3%, on a mean cholesterol content of 25 mg/100 g. From 60 analyses of a standard oil blend for fatty acids, the CV ranged from 1.2% for palmitic acid to 3.6% for eicosenoic acid (20:1). These results demonstrated that the laboratory blending process was effective in producing a homogeneous sample and verified acceptable accuracy and precision of chemical analyses (Beecher, 1996). Statistical Analysis Means and standard error of the mean were computed by the Statistical Analysis System (SAS Institute, Inc. 1991). Paired t tests (Snedecor and Cochran, 1991) were used

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TABLE 2 City Weighting Factors Based upon Regional Pork and Poultry Consumption a

to compare values across all pork or chicken cuts between the current audit and earlier Handbook 8 values. To provide a nationwide perspective for this sampling, city results for external fat thickness, physical composition, and nutrient analyses, which were physically weighted for chain market share within a city, were further mathematically weighted by region market share within the United States in calculating national means. Weight factors used to reflect regional pork and poultry consumption were determined in the “Eating in America Today” study (NLMB, 1994). Table 2 gives the regional weight factors for the cities sampled. RESULTS AND DISCUSSION Table 3 lists the mean external fat thickness measured on pork cuts sampled in the five metropolitan areas. Mean fat thickness on each of the eight cuts was less than 2.1 mm, and external fat was less on boneless than on bone-in cuts. For all cuts, mean 1996 external fat thickness was less than, or equal to, mean cut measurements from 1989. Across all comparable cuts, 1996 external fat thickness means were significantly less than in 1989 (P , 0.01; 1.4 mm in 1996 vs 2.3 mm in 1989). Meat retailing in the 1980s was characterized by a strong trend in closer trimming of external fat from fresh meat products, and results of this study suggest that this trend has continued for pork cuts into the 1990’s. The mean physical composition of pork cuts across all cities sampled is also given in Table 3. Mean total recovery of separated tissues among pork cuts ranged from 98.5 to 99.4% (data not shown). The amount of separable lean available from purchased pork cuts ranged from 92% in tenderloin to 62% in rib chops. In a comparison of the percentage lean of pork cuts in this audit with results of the 1989 Market Basket Study, in all cases, mean percentage lean was higher in 1996 cuts. Across all eight pork cuts collectively, mean percentage of raw, trimmed lean increased significantly from 1989 to 1996 (P , 0.01; 75% lean vs 81% lean, respectively). The increased lean yield for cuts in this 1996 audit is at least partially due to closer trimming of external fat by processors and retailers and may also reflect an increased muscularity and reduced fatness among pigs due to changing genetics within the swine industry. Overall, the percentage total separable fat and per-

Mean External Fat Thickness and Physical Composition of Raw Pork Cuts

TABLE 3

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TABLE 4 Mean Physical Composition of Raw Chicken Cuts

centage total refuse (bone, fat, and connective tissue) were higher in bone-in products (rib chops, sirloin roasts, and loin chops) than in boneless cuts. Bone-in cuts also had higher percentages of seam fat than external fat. The mean physical composition of chicken cuts across all cities is given in Table 4. Mean total recovery yield of separated tissues among chicken cuts ranged from 98.6 to 99.1% (data not shown). Percentage separable lean was very similar for drumsticks, thigh, and breasts (56 –58%), but substantially less for chicken wings (35%). Collectively across all chicken cuts, percentage lean means were not significantly different between the 1996 audit and 1979 Handbook 8-5 information. All pork cuts in this study yielded higher percentages of raw, trimmed lean (62 to 92%) than any of the bone-in, skin-on chicken cuts (35 to 58%). Table 5 presents nationwide means for energy, protein, fat, and cholesterol content of raw trimmed lean from pork and chicken cuts. Protein content ranged from 20.9 g/100 g (rib chop) to 23.2 g/100 g (boneless loin chop) for pork cuts, and from 18.9 g/100 g (drum) to 22.6 g/100 g (breast) for chicken. Mean protein contents within all pork cuts and within all chicken cuts were not different from Handbook 8-10 and Handbook 8-5 values, respectively. Mean fat content across all pork cuts (Table 5) was statistically unchanged (4.8 g/100 g in audit vs 5.2 g/100 g in Handbook 8-10). The fat content of raw trimmed lean of chicken breasts (2 g/100 g lean) was lower than values for drumstick, thigh, and wing (4 –5 g/100 g lean). Across all four chicken cuts collectively, mean fat content of trimmed lean was significantly higher in this audit than in the Handbook (P , 0.01; 3.9 g/100 g in audit vs 3.0 g/100 g in Handbook 8-5). With the exception of lower fat chicken breast (2.1 g/100 g lean) and pork tenderloin (2.9 g /100 g lean) and higher fat pork rib chops (6.9

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BUEGE ET AL. TABLE 5 Mean Composition of Raw Pork and Chicken Cuts (Trimmed Lean Only)

g/100 g lean), the fat content of the raw separable lean of the remaining raw pork and chicken cuts ranged from 3.8 to 5.3 g/100 g lean. The energy content of the raw trimmed lean of the eight pork cuts ranged from 118 to 151 kcal/100 g lean (Table 5). Across all pork cuts collectively, mean kcal was unchanged from Handbook 8-10 values. The mean calorie content of the separable lean of the four chicken cuts ranged from 115 to 126 kcal/100 g lean (Table 5). While breast contained less fat than the other three chicken cuts, it was also higher in protein, bringing its energy value close to other chicken cuts in this study. There was no difference in mean energy content

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across all chicken cuts in the audit and comparable values from Handbook 8-5 (121 kcal in audit vs 117 kcal in Handbook 8-5). In general, the lean from these chicken cuts provide less food energy than lean from sampled pork cuts, due to chicken’s slightly lower fat and protein levels. However, only 17 calories separated the mean of the eight pork cuts (138 kcal/100 g raw lean) from the mean of the four chicken cuts (121 kcal/100 g raw lean). Pork tenderloin is similar to chicken cuts in energy content of the trimmed lean. Mean cholesterol values for raw trimmed lean among the eight pork cuts were similar, ranging from 59 to 67 mg/100 g lean (Table 5). Collectively, audit cuts did not differ significantly from Handbook 8-10 values in cholesterol content, averaging 62 mg/100 g lean in the audit vs 59 mg/100 g lean in Handbook 8-10. While the mean cholesterol content of the trimmed lean of raw chicken breast (64 mg/100 g lean) was similar to the lean of pork cuts studied, cholesterol values for chicken thigh, drum, and wing were higher than chicken breast and pork cuts (90 –92 mg/100 g lean). Mean cholesterol values for all chicken cuts in this audit were, collectively, not significantly different from Handbook 8-5 values (84 mg/100 g vs 69 mg/l00 g, respectively). Lean from chicken wings showed the greatest change in cholesterol content from previous handbook information, increasing from 57 mg/ 100 g lean in the Handbook 8-5 to 90 mg/100 g lean in the audit. While nutrient values for trimmed lean represent nationwide means from direct chemical analysis of city lean composites, results for lean and fat (pork) or lean, fat, and skin (chicken) reflect the composition of total edible portions of entire cuts as purchased in retail packages. Nutrient values for such cuts were determined by merging the mean physical composition of a given cut from a city sampling with the nutrient composition determined for that city/cut lean composite, city fat composite, and city skin composite. Such nutrient results determined for a cut within a city were then weighted for regional consumption, and averaged across all cities to produce national cut means (Table 6). Protein contents for total cuts as purchased were lower than values based upon trimmed lean only, due to the protein-diluting effect of included fat and skin. Protein means determined in this audit for the separable lean and fat of pork cuts were not different from comparable Handbook 8-10 values (20.9 g/100 g in audit vs 20.1 g/100 g in Handbook 8-10). Protein in combined lean, fat, and skin of all four chicken cuts was lower than comparable Handbook 8-5 information (P , 0.01; 17.7 g/100 g in audit vs 19.0 g /100 g in Handbook 8-5). When trimmable fat and skin are included in the composition of pork and chicken cuts, their fat content will necessarily be higher than in trimmed lean only. While the mean fat content of the raw separable lean across the eight pork cuts averaged 4.9 g/100 g, the mean fat content for the total lean and fat associated with those cuts was 9.5 g/100 g. Based upon these findings, following dietary recommendations to remove trimmable fat from cuts before consuming (USDA/USDHHS, 1995) would result in an average fat decrease of 48% across the eight raw cuts. Across all cuts the mean fat content of total edible portions of pork cuts in this audit was not different than Handbook 8-10 values (means: 9.5 g/100 g in audit vs 11.0 g/100 g in Handbook 8-10). Similar to pork cuts, the fat content of the lean, fat, and skin of chicken cuts increased from levels in separable lean only. While the fat content of the separable lean of the four chicken cuts ranged from 2.1 to 4.8 g/100 g lean, the fat content of those same four products as purchased varied from 9.7 to 19.6 g/100 lean, fat, and skin (Tables 5 and 6). This increase in fat in chicken cuts as purchased is primarily due to the presence of skin, which comprised 8 –25% of physical composition (Table 4) and has a fat content of 40%. The mean fat content of separable lean, fat, and skin across all four 1996 chicken cuts was

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BUEGE ET AL. TABLE 6 Mean Composition of Raw Pork and Chicken Cuts (Lean, Fat and Skin)

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significantly higher than the comparable value from Handbook 8-5 (P , 0.05; 14.8 g/100 g in audit vs 12.3 g/100 g in Handbook 8-5). Dietary recommendations also strongly encourage removal of trimmable fat and skin from chicken cuts to reduce fat in the diet (USDA/USDHHS, 1995). Results across all raw chicken cuts in this study suggest that such action would reduce the total fat content of cuts as purchased by 74% (14.8 g/100 g lean, fat, and skin vs 3.9 g/100 g lean only). Energy values for total edible portions of the eight pork cuts ranged from 134 to 208 kcal/100 g lean and fat (Table 6), and 163 to 248 kcal/100 g lean, fat, and skin for the four chicken cuts. Energy values for raw separable lean and fat from pork cuts were collectively not different than comparable Handbook 8 information (175 kcal in audit vs 185 kcal/100 g lean and fat in Handbook 8-10). Energy values from the audit and Handbook 8-5 across all four chicken cuts were different (P , 0.05; 209 kcal in audit vs 192 kcal/100 g lean, fat, and skin in Handbook 8-5). Cholesterol values determined for the lean and fat portions of pork cuts from the 1996 audit (Table 6) were very similar to results for trimmed lean only (Table 5), with mean cholesterol levels across all eight cuts of 62 mg/100 g lean vs 64 mg/100 g lean and fat. Cholesterol values for lean and fat across pork cuts studied were not different from comparable Handbook 8-10 values (64 mg/100 g in audit vs 63 mg/100 g in Handbook). Cholesterol levels in the lean, fat, and skin of sampled chicken cuts were 5 to 17 mg/100 g higher than values for lean only (Tables 5 and 6). These differences were larger than noted between pork cuts compared on a lean only, and lean and fat basis, and are mainly due to the fact that chicken skin has an elevated cholesterol content and makes up a sizeable portion of these chicken products. The relative increase in cholesterol content in the separable lean, fat, and skin reflected the percentage of skin present in various chicken products. The cholesterol values determined for both chicken fat and chicken skin in this study were higher than information reported in Handbook 8-5 (98 mg vs 58 mg/100 g raw fat, and 131 mg vs 109 mg/100 g raw skin). Ground pork and ground chicken were also sampled from retail in this audit. Per 100 g raw portions, ground pork averaged 1.7 g higher in protein, 7.5 g higher in fat, 74 kcal higher in energy, and 34 mg lower in cholesterol than ground chicken (Table 6). The elevated cholesterol level in ground chicken suggests that the product contains skin or some other tissue which is a rich source of cholesterol. Mean cholesterol and fat content of ground pork in the audit were not significantly different from comparable Handbook 8-10 values. Nutrient information on ground chicken was not reported in Handbook 8-5. Table 7 provides the mean fatty acid composition of city composites of pork fat, chicken fat, and chicken skin. Mean quantities of fatty acids in these tissues are presented (g/100 g raw fat or skin), and the fatty acid composition is also expressed as a percentage of total chemical fat in the tissues. The mean fatty acid profiles found in this audit for both pork and chicken are not significantly different from information reported in the USDA Handbooks. Overall, 53% of the fatty acids in pork fat are unsaturated, compared to 61% unsaturated fatty acids in chicken fat and chicken skin. In a comparison of pork and chicken fat, pork fat contains approximately 9% more saturated fatty acids, 4% less monounsaturated fatty acids, and 5% less polyunsaturated fatty acids. When present in the diet, the 18-carbon saturated fatty acid, stearic acid, does not raise serum cholesterol (Grundy, 1994). If the quantity of that fatty acid present is subtracted from the total amount of saturated fat present in pork and chicken fat, then these fats differ by only 2% in their content of remaining saturated fatty acids (25.4% for pork

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BUEGE ET AL. TABLE 7 Mean Fatty Acid Composition of Raw Separable Pork Fat, Separable Chicken Fat, and Chicken Skin

fat vs 23.7% for chicken fat). This suggests that ingested pork and chicken fat may have similar effects on serum cholesterol. In summary, raw pork cuts evaluated in this 1996 five city, 20 store nationwide audit

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displayed a reduced external fat trim and an increased proportion of trimmed lean in the cuts, but fat and cholesterol contents were not significantly different from 1989 products. Raw chicken cuts studied were not different from 1979 Handbook information in lean yields, had increased fat in the trimmed lean, and were not statistically different in cholesterol. From an overall nutritional standpoint, the pork and chicken cuts studied did not differ appreciably in the nutrients determined in this nationwide audit. In general, the group of pork cuts studied had slightly more fat in the trimmed lean than the chicken cuts, while chicken cuts had slightly more cholesterol in the separable lean than pork cuts, per 100 g raw portions. The saturated fatty acid contents of pork and chicken fat are very similar, when adjusted for levels of stearic acid which does not elevate serum cholesterol in humans. This study also affirms the benefit to dietary fat reduction from removing skin and separable fat from chicken, and separable fat from pork, before cooked product is consumed. ACKNOWLEDGMENTS We thank the students and staff of the Animal and Food Science Department at the University of WisconsinRiver Falls for their diligent efforts in processing cuts in preparation for chemical analysis. We express our appreciation to Dr. Gary Beecher of the USDA’s Food Composition Laboratory for his suggestions related to the design of this study, and the analytical procedures used. This study was sponsored by a grant from the National Pork Producers’ Council, Des Moines, Iowa.

REFERENCES Anderson, B. A. (1983). Composition of Foods, Pork Products: Raw, Processed, Prepared. United States Department of Agriculture, Human Nutrition Information Service, Agriculture Handbook No. 8 –10. Anderson, B. A. (1992). Composition of Foods, Pork Products: Raw, Processed, Prepared. United States Department of Agriculture, Human Nutrition Information Service, Agriculture Handbook No. 8 –10. AOAC (1990). Official Methods of Analysis, 16th ed. AOAC International, Washington, DC. AOCS (1981). Official Methods and Recommended Practices of the American Oil Chemists’ Society, 4th ed. American Oil Chemists’ Society, Champaign, IL. Beecher, G. R. (1996). Research Chemist, USDA Food Composition Laboratory, Beltsville Human Nutrition Research Center, Beltsville, MD. Personal communication. Buege, D. R., Held, J. E., Smith, C. A., Sather, L. K., and Klatt, L. V. (1990). A Nationwide Survey of the Composition and Marketing of Pork Products at Retail, Research Bulletin 3509. College of Agricultural and Life Sciences, University of Wisconsin-Madison. FMI (1996). Trends in the United States—Consumer Attitudes and the Supermarket. Food Marketing Institute, Washington, DC. Grundy, S. M. (1994). Influence of stearic acid on cholesterol metabolism relative to other long chain fatty acids. Am. J. Clin. Nutri. 60, 986S–990S. NLMB (1995). Uniform Retail Meat Identity Standards. National Livestock and Meat Board, Chicago, IL. NLMB (1994). Eating in America Today: A Dietary Pattern and Intake Report. National Livestock and Meat Board, Chicago, IL. Posati, L. P. (1979). Composition of Foods, Poultry Products: Raw, Processed, Prepared. Science and Education Administration, United States Department of Agriculture, Agriculture Handbook No. 8 –5. SAS (1991). SAS User’s Guide. SAS Institute, Inc., Cary, NC. Snedecor, G. W., and Cochran, W. G. (1991). Statistical Methods, 8th ed. Iowa State Univ. Press, Ames, IA. Trade Dimensions (1995). Special Report: A Guide to Market Level Store Statistics. Trade Dimensions, Stanford, CT. USDA/USDHHS (1995). Dietary Guidelines for Americans, 4th ed. United States Department of Agriculture and United States Department of Health and Human Services, Home and Garden Bulletin No. 232.