Background 

With the United States Department of Agriculture – Food Safety and Inspection Service (USDA-FSIS) declaration of Escherichia coli O157:H7 and Shiga-toxin producing E. coli (STEC) as adulterants in non-intact raw beef products and intact raw beef products intended for non-intact use, the addition of antimicrobial interventions has become standard procedure during beef harvest and further processing. The concept of using consecutive decontamination processes in beef packing plants as a means of improving the microbiological quality of beef carcasses is beneficial (Bacon et al., 2000) to reduce microbiological contamination of beef carcass surfaces that can occur during the beef harvest process. However, because most carcass decontamination treatments do not sterilize the carcass, microorganisms remaining on carcass surfaces can easily be transferred onto freshly cut surfaces during carcass fabrication, and subsequently carried through grinding operations (Pohlman et al., 2002).  

Beef safety and quality are continuous challenges for the meat industry. With foodborne pathogens being of upmost concern, antimicrobial interventions are commonly used as a method to reduce the prevalence of pathogenic bacteria throughout the beef production process. A study conducted by Bacon et al. (2000) validated that sequential multiple hurdle interventions reduce bacteria on beef carcasses more effectively than any one intervention alone. The application of multiple interventions also can lead to the oxidation of fat and lean surfaces, which may ultimately affect the quality of ground beef products. In the past, ground beef processors have expressed concern related to the quality of beef raw materials, especially characteristics such as discoloration, off-odors, and flavors. In addition to the effectiveness of antimicrobial treatments, the impact of such treatments on meat quality factors such as color and odor (Pohlman et al., 2002) must also be considered. The objective of this research was to determine the effects of multiple applications of antimicrobial interventions on quality characteristics of beef.  

Methodology 

Eight universities (Texas A&M University, Texas Tech University, California Polytechnic State University, University of Florida, University of Missouri, North Dakota State University, Oklahoma State University, and Penn State University) collected 10 types of beef steaks (Top Blade, bone-in Ribeye, boneless Ribeye, bone-in Top Loin, boneless Top Loin, T-Bone, Porterhouse, Top Sirloin, Top Round, and Bottom Round) from 12 US cities (Houston, TX; Tampa, FL; Seattle, WA; New York City, NY; Denver, CO; Las Vegas, NV; Los Angeles, CA; Philadelphia, PA; Kansas City, MO; San Francisco, CA; Atlanta, GA; Chicago, IL). In each city, retail chains comprising the top 33% of the market share were identified and contacted to provide four stores to sample per chain. Additionally, one club store was sampled per city. In five cities (Houston, TX; Tampa, FL; Denver, CO; Las Vegas, NV; Philadelphia, PA), three types of beef steaks (boneless Ribeye, boneless Top Loin, Top Sirloin) were collected from a foodservice establishment. Brand designation, marketing claims, enhancement with percentage pumped, sodium content, form of tenderization, and any other important features were recorded on each steak, and each steak was measured for average external fat thickness and steak thickness. Approximately 60% of retail steaks (n = 1,319) were used for consumer sensory panels conducted at six universities, and the remainder of the retail steaks were used for Warner-Bratzler shear force. Foodservice steaks (n = 464) were divided in half and used for consumer sensory panels and Warner-Bratzler shear force. All steaks were cooked to an internal temperature of 70°C. Consumer sensory panels rated samples for overall like, overall like of tenderness, level of tenderness, overall like of flavor, level of beef flavor, overall like of juiciness, and level of juiciness. Four antimicrobial treatment combinations (hot water applied to hot carcass followed by hot carcass lactic acid application; hot water applied to hot carcass followed by hot carcass lactic acid application, followed by a pre-fabrication cold forequarter lactic acid spray; hot water applied to hot carcass followed by hot carcass lactic acid application, followed by a pre-fabrication cold forequarter acidified sodium chlorite spray; hot water applied to hot carcass followed by hot carcass lactic acid application, followed by a pre-fabrication cold forequarter Beefxide spray); in addition to a control (hot carcass lactic acid spray only), were used in this study. Following carcass treatments (Figure 1), trimmings were assigned to one of four treatment groups (acidified sodium chlorite, Beefxide, lactic acid or control). Trimmings were sprayed following forequarter fabrication, and were subsequently held in cold storage for 48 h prior to grinding. Ground beef patties were produced from each trimming subgroup (n = 40) and designated for shelf-life (Figure 2), consumer panel, or trained panel evaluation. Beef patty temperature, pH and color (L*, a*, b*) measurements were taken on the day of patty production, in addition to daily color measurements taken over the 5 d shelf-life period.  

Findings 

Overall, no single treatment combination appeared to significantly influence consumer perception (Figures 1, 2, and 3) or instrumental measurements (Table 1) of beef patty quality. While some visual darkening of patty color occurred by the completion of the shelf-life period, few significant changes were seen in color space values for each treatment combination (Table 2). 

Implications 

In general, findings from this study support that food safety interventions, while effective in reducing microbiological counts on product surfaces, do not negatively impact beef patty quality.