- Beef products are widely consumed and play an important role in the U.S. food system.
- Foodborne pathogens most commonly associated with beef products include STEC (shiga-toxin producing Escherichia coli) and Salmonella; improper handling and cooking have been identified as key causes of foodborne illness associated with beef products.
- The U.S. cattle inventory (as of July 1, 2014) was 95 million, with a farm gate value of approximately $44 billion.
- More than 50 percent of the total value of U.S. sales of cattle and calves comes from 5 states: Texas, Nebraska, Kansas, California, and Oklahoma.
- The average consumption of beef in the U.S. is 64 pounds per year.
- The U.S. is a top exporter of beef, with top markets being: Canada, Japan, Mexico, South Korea, and Hong Kong.
Beef cattle were first introduced to America by European colonists but the industry did not experience widespread growth until the 1800s with the advent of refrigerated rail cars. The term beef refers to meat from full grown cattle around two years of age, weighing between 1000 and 1300 pounds, and yielding approximately 450 to 600 pounds of edible red meat. The safety of the
beef supply has been a focus for U. S. regulatory agencies for over 100 years. The Department of Agriculture’s Food Safety Inspection Service (USDA-FSIS) is required by law to provide inspection for all federally-regulated beef establishments. Without an inspector present, the establishment cannot process cattle for human consumption. All beef sold in retail stores has been inspected for wholesomeness by the USDA or another state health agency and carries the “Passed and Inspected by USDA” emblem.
Agricultural animals are reservoirs for several foodborne pathogens and have a major role in their spread through food and water supplies from contact with contaminated manure. High prevalence of these pathogens is common in areas where contamination is continuous, namely farms, transportation trucks used to deliver animals, and slaughtering facilities. Between 1998 and 2008, beef accounted for 14% of foodborne illness outbreaks. The most common pathogens include: Escherichia coli O157:H7, non-O157 shiga toxin-producing E. coli (STEC), and Salmonella. CDC has reported multistate oubreaks of E. coli O157:H7 infections linked to beef products in 2007, 2008, 2009, 2010, and 2014; Salmonella Typhimurium infections associated with ground beef in 2011 and 2013, Salmonella Enteritidis associated with ground beef in 2012. One of the most devastating and well known E.Coli O157 outbreaks was associated with the hamburgers from the Jack-In-The-Box fast food chain. Follow this link to the International Outbreak Museum web page to learn more about the United States’ largest documented E.Coli O157 outbreak. Although these bacteria are destroyed by proper cooking, illnesses may result from improper handling or cooking. Good management practices during pre-harvest and processing can reduce the prevalence of foodborne pathogens associated with fresh beef products.
Although proper cooking can eradicate foodborne illness pathogens, the more control points the beef industry implements the lower the risk of carcass contamination during slaughter and processing. Implementing these practices on the farm and in the feedlot is the most cost effective way to reduce prevalence. The contamination cycle starts when animals ingest food or water contaminated with feces so feedbunks and water tanks are cleaned frequently at feedlots to help control pathogen contamination. Stresses on animals contribute to animals shedding pathogens; therefore implementation of low stress equipment and practices have become common practice at feedlots. Other pre-harvest interventions implemented include the use of direct fed microbials (DFM), microphages, and vaccinations. The DFM serve as a probiotic to help reduce incidence of pathogenic E. coli. Microphages are selected to target certain pathogens and invade and destroy bacteria, both in animals and in the feedlot environment. Some success has been reported with vaccines targeted to help reduce incidence of pathogenic E. coli and Salmonella. The intervention strategies at the farm level will never eliminate pathogen concern, however having an understanding of the on-farm sources of infection helps with better control of pathogens. At any point where fecal contamination may come in contact with other animals or even common objects such as fences, walls, or trailers, surfaces are commonly sanitized to maintain cleanliness and prevent cross contamination. This includes transportation to the processing facility and in the holding pens once the cattle have been unloaded. At many processing facilities a pre-harvest cattle wash is implemented to reduce fecal matter that could enter the facility on the hides of the animals. Along with the concern of foodborne pathogen contamination, animals are also evaluated to ensure they are fit to be slaughtered. The Federal Meat Inspection Act requires USDA to provide inspection of all live animals before entering the slaughter establishment to ensure animals are healthy and fit for slaughter. If animals are sick or have an injury, the USDA inspector will deem them as unfit for human consumption, and those animals will not enter the food supply.
Hide-On Food Safety Control
Skeletal muscle from healthy cattle have generally been considered sterile prior to slaughter, with the exception of lymph nodes. Hides are a primary source for bacteria contamination on beef carcasses that could carry contamination through the whole production process if not addressed and controlled.
Beef cattle are humanely stunned and rendered unconscious/insensible before the exsanguination process (removal of blood). Because the hide is considered a contaminated exterior surface, two knives are used to exsanguinate the beef carcasses. One knife is used to cut through the hide and another sterilized knife is used to sever the arteries in the sterile interior of the carcass to avoid cross contamination with the exterior of the hide via the knife (knives are sterilized between carcasses).
After the beef carcasses have undergone the exsanguination step, several food safety intervention options may be utilized to decontaminate the hide before it is removed from the carcass to prevent cross contamination on the sterile exterior of the hide-off carcass. Some processors will use a hot water wash designed to rinse and scrub dirt and fecal material from the exterior of the hide along with some thermal destruction of bacteria. Chemicals, such as trisodium phosphate, chlorine, or acidified chlorine may also be used to decontaminate hides. Once the hide is clean, the process of removing the hide begins.
Hide removal is the most time consuming and intricate step in the beef slaughter process as there are multiple steps conducted to prevent contamination of the internal carcass. Removal begins with a knife use at the hocks and midlines, and knife sterilization is key to preventing contamination. Steps such as placing paper on the inside flaps of hides to prevent them from swinging and touching the outside surface of clean carcasses are small steps that can have a large impact in preventing contamination to the carcasses. The initial opening of the hide is often trimmed to remove the exterior pieces of tissue that may have come in contact with the hide. Steam vacuuming is also used to decontaminate the limb removal sites at the hocks and shanks. Organic acids (lactic acid or citric acid) may be applied to the midline of the ventral (under) side of the beef carcasses before the peritoneal (internal cavity) cavity of the carcass is opened for evisceration (removal of viscera/organs).
Pre-evisceration and Evisceration
Many processors have pre-evisceration food safety interventions in place before the removal of the visceral organs takes place. This often times includes an organic acid spray and/or a hot water wash which helps to ensure decontamination of bacteria that may have occurred during the hide removal and before the evisceration process. Good manufacturing practices (GMP) must be in place for the removal of the viscera. It is imperative that no breakage of the rumen or intestines occurs that could contaminate the carcass. Knives are sterilized between processing each carcass to avoid cross contamination.
A 1993 outbreak of E. coli O157:H7 associated with undercooked ground beef patties served at a fast food chain resulted in USDA-FSIS, implementing a Zero Tolerance standard. This mandated no tolerance for visible fecal, milk or ingesta on the beef carcasses which must be excised or trimmed away from the carcasses to prevent contamination.
Final Carcass Interventions
After all processing steps for preparing the beef carcass are complete, there are typically a series of interventions before the carcass enters the cooler. Multiple hurdle technology is the most effective method for
controlling the risk of pathogens in meat and poultry products both pre- and post-harvest. Post-harvest interventions, both physical and chemical, i.e. chilling, carcasses washes, steam pasteurization, hot water pasteurization, and chemical treatments as sprays and immersions are the most effective interventions used in plants today. Typically beef carcasses undergo tested pathogen reduction interventions such as hot water pasteurization or steam pasteurization followed by treatment with an antimicrobial acid spray before entering the cooler for chilling.
Beef carcasses are chilled after harvest, typically via spray chilling methods. In the carcass coolers for approximately 24 hours following processes, carcasses are chilled with refrigeration and cold water to help drop the temperature of the carcasses rapidly to prevent growth of microorganisms. The water helps aid in the chilling process and also can serve as an antimicrobial intervention via washing which may include the addition of low concentration acids to hinder bacteria growth.
After the carcasses are properly chilled, the fabrication process begins (the disassembly of the carcass into wholesale and retail cuts). This process is done on sanitary surfaces with sterilized equipment. Employees
cutting beef have knife sterilizers and appropriate GMP dress while processing the beef products first into primal and subprimal cuts and then saleable products (i.e. roast, steaks, etc.). During this process, producers have organic acid spray cabinets for wholesale, retail, and trimmings destined for ground beef, to further inhibit microbial growth before the products are packaged. Depending on customer requirements, the processor will collect samples for microbial testing, to provide customers with a certificate of analysis or negative documentation for target organisms.
HACCP Monitoring and Control of Pathogenic Hazards
All USDA-FSIS federally inspected beef plants are required to HACCP (Hazard Analysis Critical Control Points) systems. HACCP is a systematic approach to risk assessment by identifying and controlling biological, chemical and physical hazards associated with meat and poultry products while providing documentation of the production of safe, wholesome and unadulterated meat products. FSIS has increased efforts to control foodborne pathogens by increasing requirements and regulatory efforts such as Listeria monocytogenes testing, and the addition of non-O157 STEC (O21, O45, O103, O111, O121, O145) to the adulterant list for ground beef products and trim . CDC has recognized that the implementation of HACCP into meat and poultry systems has contributed to the reduction in the incidence of foodborne illness overall in the United States since 1996. Each inspected beef plant has HACCP plans for their system that have undergone risk assessment and implementation of critical control points to help prevent, eliminate, and reduce biological hazards.
Sanitation and GMPs
Sanitation is an imperative pre-requisite program for a beef plant’s HACCP plan. By having clean facilities and equipment, the beef plants can successfully control bacteria. Sanitation is done with detergents and sanitizers designed for meat processing facilities to help clean fat and protein residues along with eliminating bacteria biofilms. The processing area is cleaned every night before the start of production with a complete wash down, detergent foaming, scrubbing, and multiple hot water rinses and sanitizing steps. Along with daily cleaning, programs are in place for operational sanitation procedures during the processing day to keep facilities and equipment clean.
Along with facility cleanliness, beef plants also have strict GMP programs for their employees. Common practices include: hair nets, frocks, gloves, rubber boots, hand washing, no jewelry, knife sterilization, operational table clean-up, and boot sanitizers.
Antibiotics may be given to prevent or treat disease in cattle but all medications given to cattle require a withdrawal period; this means animals are not given any medication for the required amount of time prior to slaughter. During the withdrawal period residues of the medicine or antibiotics exit the animal’s system. At slaughter random samples (typically kidneys) are taken by FSIS and tested for residues, with very low percentages of residue violations being reported.
Many steps are in place to ensure the product at the retail level is safe for human consumption but safe handling of meat products may not be practiced at home. When shopping, consumers should make sure that beef products are cold (< 40°F), put in a plastic bag before placing in the grocery cart, and purchased last in order to control temperature and avoid cross-contamination with other foods. Temperature control is extremely important with beef products prior to cooking; meat should always be properly stored and thawed. Fresh beef should be consumed within three days of purchasing or it should be frozen. Safe handling recommendations for consumers include storing meat below ready to eat foods in the refrigerator; thawing either in the refrigerator, microwave or under cold running water; washing hands before and after handling meat; using clean knives and cutting boards designated for meat; always washing utensils well in hot soapy water after each use, and using a meat thermometer to ensure ground beef or tenderized steaks are cooked to a minimum temperature of 160°F, and steaks and roasts are cooked to a minimum of 145°F.
In 2014, Americans consumed a total of 24.1 billion pounds of beef amounting to $95 billion dollars. While the retail price of Choice beef has steadily been increasing (current average $5.97/lb), the overall consumption of beef has steadily decreased since 2007 (28.1 lb/person). In the Population Survey Atlas of Exposures 2006-2007, 46.2% of the survey cohort reported eating beef at home within the past 7 days. Furthermore, 26.1% of the survey population reported eating beef outside of the home within the past 7 days.
Beef is a source of complete protein as well as an excellent source of phosphorus, protein, selenium, Vitamin B12 and zinc and a good source of iron, niacin, Vitamin B6, and Riboflavin. In fact, red meat account for 61% of vitamin B-12 in the U.S. food supply. This nutritional powerhouse plays a role in helping with red blood cell development and preventing iron deficiencies, one of the most common nutritional deficiencies in the U.S. Conjugated linoleic acid (CLA), a derivative of the essential fatty acid, linoleic acid, may potentially protect against cancer, heart disease, and diabetes and may enhance immune function. Beef accounts for approximately 36% of the total amount of CLA consumed.