Yun-Hwa P. Hsieh, Carla J. Wetzstein, and Nancy R. Green

An AAES study has identified a widespread problem in Alabama retail markets: much of the state's fresh ground pork and pork sausage contain significant amounts of meats other than pork. The major adulterating species in these pork products are beef, poultry, and mutton. Mixing undeclared species in meat products is illegal under food labeling regulations mandated and monitored by the United States Department of Agriculture (USDA), as well as by state agencies. Apart from regulatory requirements, prevention of undeclared species in meat products is important for economic, religious, and health reasons.

A total of 129 samples, including 42 ground pork samples and 87 fresh pure-pork sausage products, were collected by Alabama food inspectors from different manufacturers and retail stores across the state as part of routine, regulatory sample collections. Samples were analyzed to detect beef, poultry, and mutton substitution and to confirm that pork was actually used in the products. Researchers used Enzyme-Linked Immunosorbent Assay, a sensitive technique that can identify proteins from specific animal tissues.

Ninety percent of the ground pork samples, all of which were market-made, contained beef and/or poultry (Table 1). Sheep tissue was not found in the ground pork samples. The 87 pork sausage samples included 42 name-brands and 45 market-made products. Overall, 54% of the pork sausage samples contained undeclared meat. Twelve percent of the name-brands were in violation of labeling regulations, while 93% of market-made sausage was adulterated.

Of the 38 adulterated ground pork samples, 99% contained beef, and 18% contained poultry (Figure 1). Of the 47 adulterated sausage samples, 96% contained beef; 38%, poultry; and 2%, mutton. In ground pork, 84.6% of the adulterated samples were contaminated by one species, and 15.4% were contaminated by two species (Figure 2). In adulterated pork sausage samples, 62% were contaminated with a single species, 36% with two species, and 2% with three species.

Figure 1. The pattern of species contamination in adulterated ground pork and pork sausage samples.

Figure 2. The distribution of contaminating species in fresh pork samples.

Since beef is more expensive than pork, there is no apparent economic reason for the addition of beef to pork products. Results indicated that the primary problem centers around the meat grinding operation. Market managers readily admitted that they did not routinely clean grinders when changing from ground beef to another meat. Poultry, on the other hand, is cheaper than pork, indicating the possibility of intentional adulteration for economic reasons. The addition of lamb meat to pork is thought to be done to utilize the unmarketable trimmings left from expensive meats and to extend the bulk of pork products. Fatter trimmings from beef or poultry also could be added to ground pork products to extend bulk. USDA allows a fat limit of 50% for fresh pork sausage, while regular ground beef can contain only 30% fat. There is no fat content limit for fresh ground pork.

Most of the adulterated meat contained 1-10% of undeclared species (Table 2). Low concentrations (less than 1 %) of meat contamination may be due to poor market grinder cleaning practices. However, the presence of higher concentrations and multiple undeclared species in meat products are likely indications of intentional adulteration.

As revealed in this study, current retail practice in Alabama meat markets shows a widespread species adulteration. In the past, the Alabama Department of Agriculture did not implement the meat species monitoring program at the retail level due to insufficient facilities and technology. Recently, Alabama strengthened its retail meat regulatory program to discourage meat adulteration.

Hsieh is an Assistant Professor, Wetzstein is a Graduate Research Assistant, and Green is a Professor of Nutrition and Food Science.