Reduction of Pathogens Using Hot Water and Lactic Acid on Beef Trimmings

Beef trimmings from young or mature beef cattle were obtained commercially. Trimmings within age type then were inoculated with about 6.0 log₁₀ CFU/mL of rifampicin-resistant. Escherichia coli O157:H7 and Salmonella typhimurium (ATCC 13311) were randomly assigned to 1 of 3 treatments (control; 95 °C hot water alone, or with 2% L-lactic acid). After treatment, trimmings were ground, held for 0, 14, 28, or 42 d in chub packages at 4 °C, and total aerobic plat counts, E. coli O157:H7, and S. typhimurium counts were determined. Non-inoculated trimmings were also treated and samples were evaluated for pH, fat, moisture, TBA, meat color by colorimeter, and meat color, and odor by trained sensory panels. Trimmings treated with water or hot water plus lactic acid reduced levels of E. coli O157:H7 and S. typhimurium and tended to be darker after treatment. Meat odor in the final product was not affected by treatment.     

Solubilized Cellulose and Dehydrated Potato Extract in Cooked, Low-fat Comminuted Beef

ABSTRACT The optimal level of use of NP-5, a dehydrated potato extract, and solubilized cellulose (SC), a highly functional form of cellulose in a comminuted beef product was determined so that water holding capacity (WHC), cooking yield and resistance to rancidity would be maximized. NP-5 was a very effective antioxidant and water binding ingredient at 1.5%. Addition of SC resulted in a more moist product and improved the cooking yield compared to the control. Addition of NP-5 and SC resulted in extended overall storage stability.     

Triose Phosphate Isomerase as an Endogenous Time-temperature Integrator to Verify Adequacy of Roast Beef Processing

Bovine muscle type had a large influence on the initial activity and heat stability of triose phosphate isomerase (TPI). TPI activity in the round muscles was more heat labile than in the chuck muscles. Residual TPI activity in bovine semimembranosus muscle was determined after cooking using adequate and corresponding inadequate U.S. Department of Agriculture processing schedules. In both water bath and pilot oven studies, TPI activity was similar in adequately processed beef (about 2 U/g) and increased when inadequately processed by reducing the holding time by 0.5 and 1.0 log at each temperature. Taken together, these results suggested that TPI could be used as an endogenous time-temperature indicator to verify processing adequacy of roast beef if the muscle used in the product was known.     

Effects of storage under a modified atmosphere on the microbiological and organoleptic qualities of ground beef prepared from pasteurized manufacturing beef

A 40‐kg lot of manufacturing beef, i.e. meat used for the production of ground beef products, was collected at a beef packing plant. The lot was divided into two batches. One batch was pasteurized by immersion in water at 85 °C for 60 s, the other batch was not pasteurized. Both batches were then ground. The ground meat was packed in overwrapped trays, which were master packaged under a modified atmosphere of 70% O₂ : 30% CO₂. The master packs were stored at 2 °C for up to 12 days. At the time of pack preparation and at 2‐day intervals, a master pack containing pasteurized and another pack containing unpasteurized meat, were opened and retail packs from each master pack were displayed at 4 °C for 3 days. Samples for microbiological analysis were obtained at the times of opening master packs and at the end of display. Displayed meat was assessed daily for colour, discoloration and retail appearance, and for odour intensity and acceptability at the end of display. After either a period of storage or a period of storage and display, the numbers of bacteria recovered from pasteurized meat were less than the numbers recovered from unpasteurized meat. The colour of pasteurized meat was perceived as being paler than that of unpasteurized meat, but discoloration was similar or less, and retail appearance was similar or better for pasteurized than unpasteurized meat at all times. The odours of displayed, pasteurized meat were generally somewhat less intense and more acceptable than those of unpasteurized meat. The findings indicate that pasteurization of manufacturing beef to improve the microbiological safety of ground beef provides a product of acceptable appearance and enhanced stability during storage under a modified atmosphere and subsequent display in air.     

Solution Enhancement and Post-enhancement Storage Effects on the Quality, Sensory, and Retail Display Characteristics of Beef Triceps Brachii Muscles

Beef triceps brachii muscles (6 d postmortem; n= 15; muscle sections n= 45) were sectioned into 3rds and allocated to 1 of 3 treatments. The treatments were untreated (CNT), or injected at a 12% pump rate with either tap water‐only (H₂O) or a solution comprising tetrasodium pyrophosphate and sodium chloride (TSPP/ NaCl) at 0.4% and 1.0% target final product weight concentrations, respectively. Each muscle (comprising all 3 treatments) was then allocated to 2, 14, or 28 d of vacuum‐packaged 1°C storage. Purge losses during storage were greatest (P < 0.05) for H₂O muscles and least (P < 0.05) for TSPP/NaCl muscles. Purge losses also increased (P < 0.05) from 2 d to 14 d of storage. Steaks enhanced with TSPP/NaCl had less (P < 0.05) free water and lower (P < 0.05) cooking losses than either CNT or H₂O steaks. Storage duration did not affect (P > 0.05) Warner‐Bratzler shear force (WBS) or sensory tenderness, but juiciness decreased (P < 0.05) with increased storage duration. While storage duration did not impact (P > 0.05) instrumental color characteristics, aerobic plate counts generally increased during storage. The TSPP/NaCl steaks had lower (P < 0.05) WBS values and improved (P < 0.05) sensory tenderness and juiciness characteristics compared with CNT or H₂O steaks. While CNT steaks had greater (P < 0.05) L* values (lightness) than TSPP/NaCl steaks, TSPP/NaCl steaks had similar (P > 0.05) oxymyoglobin proportions (630/580 nm) and a* values (redness) as CNT steaks. These results suggest enhancement with TSPP/NaCl can improve triceps brachii yield and palatability characteristics. Increased post‐enhancement storage did not impact or worsened palatability while increasing purge losses, suggesting general deleterious effects of increased postmortem storage for this muscle.     

Modeling the inactivation of Escherichia coli O157:H7 and Uropathogenic E. coli in ground beef by high pressure processing and citral

Escherichia coli O157:H7 are a well-known intestinal foodborne pathogen which were responsible for numerous foodborne illness outbreaks. Uropathogenic E. coli (UPEC) are common contaminants in meat and poultry, and may cause urinary tract infections after colonizing the gastrointestinal tract followed by accidental transfer of contaminated feces from the anus to the urethra. High pressure processing (HPP) has been demonstrated an effective means in reducing pathogenic E. coli levels in meat and poultry. Citral, an antimicrobial, also demonstrated some inactivation effect on pathogenic E. coli in ground beef (ca. 0.5–1.0 log CFU/g reduction at 1% w/w without HPP). With HPP alone, to achieve 5 log CFU/g reduction required a 500 MPa level and 15 min (for both O157:H7 and UPEC). However, 1% of citral addition may lower the pressure requirement to 380 MPa and 15 min which could reduce the food quality damage. To effectively inactivate E. coli O157:H7 and UPEC in meat, high pressure processing (HPP) in combination with the antimicrobial citral was studied. Ground beef inoculated with E. coli O157:H7 or UPEC were treated at different HPP conditions (250–350 MPa; 10–20 min), and citral (0.75–1.25%, w/w) following a central composite experimental design. Quadratic linear regression equations were developed to describe and predict the reductions of E. coli O157:H7 (R² = 0.93, p < 0.001) and UPEC (R² = 0.92, p < 0.001). Dimensionless nonlinear models consisting of three impact factors were also developed and compared with the linear models. These models were experimentally validated. Citral enhanced the inactivation of pathogenic E. coli, increasing the effectiveness of the HPP process. The models may assist the food industry and regulatory agencies in risk assessment of E. coli O157:H7 and UPEC on ground meats.     

Inhibitory activity of Asian spices on heterocyclic amines formation in cooked beef patties

Heterocyclic amines (HCAs) are mutagenic compounds formed when foods are cooked at high temperatures. Numerous reports have shown that natural antioxidants from spices, fruits, chocolate, and tea can inhibit formation. In this study, we evaluated HCA formation in the presence of 5 of Asian spices: galangal (Alpinia galangal), fingerroot (Boesenbergia pandurata), turmeric (Curcuma longa), cumin (Cuminum cyminum), and coriander seeds (Coriandrum sativum). HCA levels were compared to patties containing rosemary (Rosmarinus officinalis), of which the inhibitory effect is well documented. Inhibition of HCA formation by the spices was evaluated in beef patties cooked at 204 °C (400 °F) for 10 min. All spices were mixed into patties at 0.2% before cooking, and HCAs levels were measured in the final product. All patties, including the control, contained 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl -6-phenylimidazo [4,5-b]pyridine (PhIP). The average HCA content of the control patties was 7 ng/g MeIQx and 6.53 ng/g PhIP. Turmeric (39.2% inhibition), fingerroot (33.5% inhibition), and galangal (18.4% inhibition) significantly decreased HCAs compared with the control. But, only turmeric and fingerroot were as effective as rosemary in preventing HCA formation. The HCA inhibition in patties containing spices was significantly correlated to the total phenolic content (R(2) = 0.80) and the scavenging activity (R(2) = 0.84) of the spices as measured by the 2,2-diphenyl-β-picrylhydrazyl assay. Results of this study suggest that addition of Asian spices can be an important factor in decreasing the levels of HCAs in fried beef patties.     

Retail display evaluation of steaks from select beef strip loins injected with a brine containing 1% ammonium hydroxide. Part 1: Fluid loss, oxidation, color, and microbial plate counts

Select beef loin pairs (n = 10) were injected (10% pump) with brine containing either 4.5% sodium-based phosphates, (CON), or 1% ammonium hydroxide treatment (AHT). Both brines also contained 3.6% NaCl and 1% Rosemary Herbalox. Steaks cut from loins were high oxygen (80% O(2)/20% CO(2)) modified atmosphere packaged, stored 4 d at 4 °C in the dark to simulate transportation, and then placed in retail display for 14 d (4 °C). On day 0, 7, and 14 of retail display steak properties were measured. Purge from AHT steaks was higher than CON (P < 0.05). Panelists were not able to visually discriminate between AHT and CON steaks through the first 6 d of retail display. After day 6, panelists rated AHT steaks higher for muscle color, percent discoloration, and overall color. Steaks from both treatments started at day 0 retail display with similar total plate counts (P > 0.05). Microbial counts increased more rapidly for AHT steaks than CON steaks (P < 0.05). AHT and CON steaks were not different in terms of lipid oxidation through day 7 retail display. By day 14 retail display CON steaks were above the threshold for consumer perception of oxidized flavors in fresh meat. However, results also indicated the AHT and CON steaks were no longer acceptable by day 14 in terms of color, were questionable in terms of microbial load, and likely were beyond their reasonable shelf life. Based on retail display properties, results indicated 1% AHT could successfully replace 4.5% SP in a meat injection brine. Practical Application: The research in this report compares steaks that have been injected with a commercial brine formulated with SP to steaks that have been injected with a brine, where the SP in the formulation are replaced with 1% AHT. Ammonium hydroxide is an USDA-FSIS approved ingredient in brines injected into fresh meats. Successful replacement of sodium phosphate with ammonium hydroxide would allow processors to significantly reduce the sodium content of injected fresh meat.     

Omega-3 fatty acids affected human perception of ground beef negatively

The objective was to determine the impact of increasing levels of Eicosapentaenoic acid (EPA; C20:5n3) and Docosahexaenoic acid (DHA; C22:6n3) on beef palatability. Two commercial supplements of EPA and DHA were added to 85% lean ground beef patties (176.2 ± 3.76 g) with different levels (0, 0.3, 0.4, 0.5, 0.6, 0.7, and 1% as-is). Olive oil was added so that all patties contained 1% added lipid. A control treatment was also prepared with no supplement or olive oil. Sensory evaluation and fatty acid analysis was conducted. Ground beef flavor decreased linearly (P<0.001) with increasing levels of EPA and DHA. Off-aroma and off-flavor increased linearly and then plateaued with increasing levels of EPA (P<0.0001). In conclusion, EPA had a greater negative impact on beef palatability than DHA. Also, the panelists were more sensitive to EPA in off-flavor perception than off-aroma.