Browsing by Author "Miller, Markus F. (TTU)"
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Item Bio-Mapping of Microbial Indicators to Establish Statistical Process Control Parameters in a Commercial Beef Processing Facility(2022) Vargas, David A. (TTU); Rodríguez, Karla M. (TTU); Betancourt-Barszcz, Gabriela K. (TTU); Ajcet-Reyes, Manoella I. (TTU); Dogan, Onay B. (TTU); Randazzo, Emile; Sánchez-Plata, Marcos X. (TTU); Brashears, Mindy M. (TTU); Miller, Markus F. (TTU)The objective was to conduct a bio-mapping of microbial indicators to determine statistical process control (SPC) parameters at a beef processing plant to establish microbiological baselines and process control parameters to support food safety management decisions. EZ-Reach™ swabs were used to collect 100 cm2 area samples at seven different locations throughout the beef processing line at four different regions on the carcass. Each of the eight sampling days evaluated included three samples collected per sampling location/carcass region for a total of 84 samples per day. Enumeration of total aerobic bacteria, Enterobacteriaceae, and Escherichia coli was performed on each sample. Microbial SPC parameters were estimated for each sampling point. Statistical differences between sampling points for all carcass locations (p < 0.001) followed an overall trend with higher values at pre-and post-evisceration with a continuous decrease until final interventions with a slight increase in counts during the chilling process and a final increase after fabrication. Variability at sampling points is the result of the nature of the process and highlights open opportunities for improvement of the food safety system. Microbial baselines and SPC parameters will help support decision making for continuous process improvement, validation of intervention schemes, and corrective action implementation for food safety management.Item Biomapping of microbial indicators on beef subprimals subjected to spray or dry chilling over prolonged refrigerated storage(2021) Casas, Diego E. (TTU); Manishimwe, Rosine (TTU); Forgey, Savannah J. (TTU); Hanlon, Keelyn E. (TTU); Miller, Markus F. (TTU); Brashears, Mindy M. (TTU); Sanchez-Plata, Marcos X. (TTU)As the global meat market moves to never frozen alternatives, meat processors seek opportunities for increasing the shelf life of fresh meats by combinations of proper cold chain management, barrier technologies, and antimicrobial interventions. The objective of this study was to determine the impact of spray and dry chilling combined with hot water carcass treatments on the levels of microbial indicator organisms during the long-term refrigerated storage of beef cuts. Samples were taken using EZ-Reach™ sponge samplers with 25 mL buffered peptone water over a 100 cm2 area of the striploin. Sample collection was conducted before the hot carcass wash, after wash, and after the 24 h carcass chilling. Chilled striploins were cut into four sections, individually vacuum packaged, and stored to be sampled at 0, 45, 70, and 135 days (n = 200) of refrigerated storage and distribution. Aerobic plate counts, enterobacteria, Escherichia coli, coliforms, and psychrotroph counts were evaluated for each sample. Not enough evidence (p > 0.05) was found indicating the hot water wash intervention reduced bacterial concentration on the carcass surface. E. coli was below detection limits (<0.25 CFU/cm2) in most of the samples taken. No significant difference (p > 0.05) was found between coliform counts throughout the sampling dates. Feed type did not seem to influence the (p > 0.25) microbial load of the treatments. Even though no immediate effect was seen when comparing spray or dry chilling of the samples at day 0, as the product aged, a significantly lower (p < 0.05) concentration of aerobic and psychrotrophic organisms in dry-chilled samples could be observed when compared to their spray-chilled counterparts. Data collected can be used to select alternative chilling systems to maximize shelf life in vacuum packaged beef kept over prolonged storage periods.Item Effects of Sex Class, a Combined Androgen and Estrogen Implant, and Pasture Supplementation on Growth and Carcass Performance and Meat Quality of Zebu-Type Grass-Fed Cattle(2021) Huerta-Leidenz, Nelson (TTU); Jerez-Timaure, Nancy; Sarturi, Jhones Onorino (TTU); Brashears, Mindy M. (TTU); Miller, Markus F. (TTU); Moya, Alexis; Godoy, SusmiraForty-seven Zebu calves were used to determine the effects of class (bull or steer), supplementation (SUPPL, a poultry litter-based supplement or mineral supplementation), and implant (20 mg estradiol combined with 120 mg of trenbolone acetate or no implant) on growth and carcass performance and beef eating quality. The average daily gain (ADG) of implanted cattle significantly increased for steers, but not for bulls. The SUPPL treatment increased ADG by 8.63% from day 0 to end, and shortened in 73.3 d the time to reach 480 kg BW (p < 0.01). Compared to bulls, the steer carcasses exhibited more desirable maturity and finish scores, thicker back fat (p < 0.05), and yielded greater (p < 0.01) percentages of high-value boneless subprimals (HVBLS) (+1.64%) and total cuts (1.35%). The SUPPL bulls dressed 2.63 and 1.63% greater than non-supplemented bulls and SUPPL steers, respectively (p < 0.05). Meat sensory quality was subtly affected (p < 0.05) by sex class or supplementation. The implant did not affect (p > 0.05) shear force or sensory ratings. The supplementation improved key growth performance traits while it adversely affected tenderness-related sensory traits. The implant enhanced the rate of gain of steers only, without improving cut-out yields or inducing adverse effects on palatability traits in both steers and bulls.Item Efficacy of Common Antimicrobial Interventions at and above Regulatory Allowable Pick-Up Levels on Pathogen Reduction(2023) Blandon, Sabrina E. (TTU); Vargas, David A. (TTU); Casas, Diego E. (TTU); Sarasty, Oscar (TTU); Woerner, Dale R. (TTU); Echeverry, Alejandro (TTU); Miller, Markus F. (TTU); Carpio, Carlos E. (TTU); Sanchez-Plata, Marcos X. (TTU); Legako, Jerrad F. (TTU)The objective of this study was to evaluate the food safety efficacy of common antimicrobial interventions at and above required uptake levels for processing aids on the reduction of Shiga-toxin producing E. coli (STEC) and Salmonella spp. through spray and dip applications. Beef trim was inoculated with specific isolates of STEC or Salmonella strains. Trim was intervened with peracetic or lactic acid through spray or dip application. Meat rinses were serially diluted and plated following the drop dilution method; an enumerable range of 2–30 colonies was used to report results before log transformation. The combination of all treatments exhibits an average reduction rate of 0.16 LogCFU/g for STEC and Salmonella spp., suggesting that for every 1% increase in uptake there is an increase of 0.16 LogCFU/g of reduction rate. There is a statistical significance in the reduction rate of Shiga-toxin producing Escherichia coli in relation to the uptake percentage (p < 0.01). The addition of explanatory variables increases the R2 of the regression for STEC, where all the additional explanatory variables are statistically significant for reduction (p < 0.01). The addition of explanatory variables increases the R2 of the regression for Salmonella spp., but only trim type is statistically significant for reduction rate (p < 0.01). An increase in uptake percentages showed a significant increase in reduction rate of pathogens on beef trimmings.Item Establishment of a preliminary baseline of Salmonella presence on pork and goat carcasses harvested in the Bahamas to address food and nutritional security interventions(2018) Hanlon, Keelyn E. (TTU); Echeverry, Alejandro (TTU); Miller, Markus F. (TTU); Brashears, Mindy M. (TTU)• Small island developing states, such as the Bahamas, struggle with productive agricultural systems. This ultimately influences the food and nutritional security of the country. • Agricultural production systems need to be established in small island states, such as the Caribbean to improve food and nutritional security. • Baselines of foodborne pathogens, such as Salmonella, are documented in many developed regions throughout the world. There are gaps in these baselines, however, which need to be established to effectively target food safety intervention strategies.Item Flavor Development of Ground Beef from 3 Muscles, 3 USDA Quality Grades, and 2 Wet-Aging Durations(2024) Hernandez, M. Sebastian (TTU); French, Caroline N. (TTU); Legako, Jerrad F. (TTU); Thompson, Leslie D. (TTU); Miller, Markus F. (TTU); Brooks, J. Chance (TTU)The objective of this study was to understand the influence of USDA quality grade, muscle, and aging duration on ground beef flavor development. Prime (PR), Low Choice, and Standard quality grade beef subprimals were collected and aged for either 21 or 42 d. Following aging, subprimals were fabricated into gluteus medius (GM), biceps femoris (BF), and serratus ventralis (SV) then ground and formed into patties. Raw patties were designated for proximate composition, fractionated fatty acids, and thiobarbituric acid reactive substances (TBARS). Cooked patties were designated for consumer sensory analysis, volatile compound analysis, and TBARS. Patties were cooked on a preheated griddle to 72°C. All data were analyzed as split-split plot where quality grade served as the whole plot factor, muscle as the subplot factor, and aging duration as the sub-subplot factor. Significance was determined at P < 0.05. A quality grade × muscle interaction was observed for moisture, where regardless of muscle, PR subprimals had the lowest moisture percentage (P < 0.05). Raw TBARS was not influenced by any interactions or main effects (P > 0.05). Individually, the BF and 42 d aged subprimals had the greatest cooked malondialdehyde concentration (P < 0.05). Patties from GM aged for 21 d were rated higher for flavor liking compared to GM aged for 42 d and SV aged for 21 and 42 d (P < 0.05). GM patties aged for 21 d were rated higher for overall liking compared to GM patties aged for 42 d (P < 0.05). Quality grade did not influence any lipid-derived volatile compounds (P > 0.05). The SV produced less Maillard reaction products (P < 0.05). Aging for 42 d increased lipid-derived volatiles (P < 0.05). Consumer liking of aged product is dependent on muscle. Aging recommendations should be muscle-specific to maximize beef eating experience.Item In-Plant Intervention Validation of a Novel Ozone Generation Technology (Bio-Safe) Compared to Lactic Acid in Variety Meats(2021) Vargas, David A. (TTU); Casas, Diego E. (TTU); Chávez-Velado, Daniela R. (TTU); Jiménez, Reagan L. (TTU); Betancourt-Barszcz, Gabriela K. (TTU); Randazzo, Emile; Lynn, Dan; Echeverry, Alejandro (TTU); Brashears, Mindy M. (TTU); Sánchez-Plata, Marcos X. (TTU); Miller, Markus F. (TTU)The objective of this experiment was to compare the antimicrobial efficacy of an aqueous ozone intervention and a lactic acid solution on natural microbiota of variety meats in a commercial beef processing plant. EZ-Reach™ swabs were used to collect 100 cm2 area samples before and after ozone and lactic acid intervention application for three different offals (head, heart, and liver). Each repetition included 54 samples per variety meat and antimicrobial for a total of 162 samples per repetition. Enumeration of total aerobic bacteria (APC) and Escherichia coli (EC) was performed on each sample. Microbial counts for both microorganisms evaluated were significantly reduced (p < 0.001) after lactic acid immersion (2–5%) and ozone intervention for all variety meats, with the exception of ozone intervention in EC counts of the heart samples. APC after lactic acid intervention was reduced on average by 1.73, 1.66, and 1.50 Log CFU/sample in the head, heart, and liver, respectively, while after ozone intervention, counts were reduced on average by 1.66, 0.52, and 1.20 Log CFU/sample. EC counts after lactic acid intervention were reduced on average by 0.96, 0.79, and 1.00 Log CFU/sample in the head, heart, and liver, respectively, while after ozone intervention, counts were reduced on average by 0.75, 0.62, and 1.25 Log CFU/sample. The aqueous ozone antimicrobial scheme proved to be a promising intervention for the in-plant reduction of indicator levels in variety meats, specifically heads, hearts, and livers.Item In-plant validation of novel on-site ozone generation technology (Bio-safe) compared to lactic acid beef carcasses and trim using natural microbiota and salmonella and e. coli o157:H7 surrogate enumeration(2021) Casas, Diego E. (TTU); Vargas, David A. (TTU); Randazzo, Emile; Lynn, Dan; Echeverry, Alejandro (TTU); Brashears, Mindy M. (TTU); Sanchez-Plata, Marcos X. (TTU); Miller, Markus F. (TTU)The purpose of this study was to evaluate the antimicrobial efficacy of an aqueous ozone (Bio-Safe) treatment and lactic acid solutions on natural microbiota and E. coli O157:H7 and Salmonella surrogates on beef carcasses and trim in a commercial beef processing plant. For every repetition, 40 carcass and 40 trim swabs (500 cm2 ) were collected. Samples were taken using EZ-Reach™ swabs, and plated into aerobic plate count (APC), coliform, and E. coli Petrifilm™ for enumeration. In addition, a five-strain cocktail (MP-26) of E. coli surrogates was inoculated onto trim. For every trim surrogate repetition, 30 trim pieces were sampled after attachment and after ozone intervention. Samples were diluted and counts were determined using the TEMPO® system for E. coli enumeration. Ozone and lactic acid interventions significantly reduced (p < 0.003) bacterial counts in carcasses and trim samples. Moreover, lactic acid further reduced APC and coliforms in trim samples compared to ozone intervention (p < 0.009). In the surrogate trials, ozone significantly reduced (p < 0.001) surrogate concentration. Historical data from the plant revealed a reduction (p < 0.001) of presumptive E. coli O157:H7 in trim after a full year of ozone intervention implementation. The novel technology for ozone generation and application as an antimicrobial can become an alternative option that may also act synergistically with existing interventions, minimizing the risk of pathogens such as Salmonella and E. coli O157:H7.Item Influence of demographic factors on sheepmeat sensory scores of American, Australian and Chinese consumers(2020) O'Reilly, Rachel A.; Pannier, Liselotte; Gardner, Graham E.; Garmyn, Andrea J. (TTU); Luo, Hailing; Meng, Qingxiang; Miller, Markus F. (TTU); Pethick, David W.Along with animal production factors, it is important to understand whether demographic factors influence untrained consumer perceptions of eating quality. This study examined the impact of demographic factors and sheepmeat consumption preferences on eating quality scores of American, Australian and Chinese untrained consumers. M. longissimus lumborum (LL) and m. semimembranosus (SM) were grilled according to sheep Meat Standards Australia protocols and evaluated by 2160 consumers for tenderness, juiciness, flavour and overall liking. Linear mixed effects models were used to analyse the impact of demographic factors and sheepmeat consumption habits on eating quality scores. Consumer age, gender, number of adults in a household and income had the strongest effect on sensory scores (P ≤ 0.05), although, the impact was often different across countries. Frequency of lamb consumption had an impact on sensory scores of American, Australian and Chinese consumers but larger sample sizes in some underrepresented subclasses for Australian and Chinese consumers are needed. Results suggest it is important to balance sensory panels for demographic factors of age, gender, number of adults and income to ensure sensory preferences are accurately represented for these particular populations.Item Microbial growth study on pork loins as influenced by the application of different antimicrobials(2021) Vargas, David A. (TTU); Miller, Markus F. (TTU); Woerner, Dale R. (TTU); Echeverry, Alejandro (TTU)The use of antimicrobials in the pork industry is critical in order to ensure food safety and, at the same time, extend shelf life. The objective of the study was to determine the impact of antimicrobials on indicator bacteria on pork loins under long, dark, refrigerated storage conditions. Fresh boneless pork loins (n = 36) were split in five sections and treated with antimicrobials: Water (WAT), Bovibrom 225 ppm (BB225), Bovibrom 500 ppm (BB500), Fit Fresh 3 ppm (FF3), or Washing Solution 750 ppm (WS750). Sections were stored for 1, 14, 28, and 42 days at 2–4◦C. Mesophilic and psychrotrophic aerobic bacteria (APC-M, APC-P), lactic acid bacteria (LAB-M), coliforms, and Escherichia coli were enumerated before intervention, after intervention, and at each storage time. All bacterial enumeration data were converted into log10 for statistical analysis, and the Kruskal–Wallis test was used to find statistical differences (p < 0.05). Initial counts did not differ between treatments, while, after treatment interventions, treatment WS750 did not effectively reduce counts for APC-M, APC-P, and coliforms (p < 0.01). BB500, FF3, and WS750 performed better at inhibiting the growth of indicator bacteria when compared with water until 14 days of dark storage.Item Multiple Interventions for Improving Food Safety Practices in 2 Small Beef Abattoirs of Honduras and Associated Impacts on Risk-Mitigation Management(2020) Casas, Diego (TTU); Calle, Alexandra (TTU); Bueso, Mariely (TTU); Huerta-Leidenz, Nelson (TTU); Miller, Markus F. (TTU); Brashears, Mindy M. (TTU)Mitigation of risk for Shiga toxin-producing Escherichia coli (STEC) and Salmonella contamination was evaluated after a multiple-intervention approach (comprising food safety education and training, implementation of customized food safety practices and programs, and environmental monitoring programs with audits and corrective actions) in 2 small Honduran beef abattoirs. Previously, neither abattoir had food safety programs in place nor were they subjected to strict food safety regulatory surveillance. Abattoirs A and B were sampled on 4 nonconsecutive months each. Swab samples of abattoir A (n = 160, 40 samples per sampling date) and abattoir B (n = 78, 16-22 samples per sampling date) were taken from direct and indirect food contact surfaces, screened by BAX real-time polymerase chain reaction (PCR) assays and confirmed using immunomagnetic separation, selective media, and latex agglutination. In abattoir A, Salmonella presence was negligible, whereas presumptive STECs were present in 10%, 12.5%, 0%, and 5% of the environmental samples respective to each sampling month, indicating a reduction of STEC (P =.06) by the third and fourth sampling months. Conversely, presumptive STEC presence was negligible in abattoir B, whereas Salmonella presence for each sampling month was of 5.6%, 6.3%, 27.3%, and 0.0%, respectively. Upon the increased pathogen presence detected on the third sampling month, additional actions were taken to reinforce the implementation of food safety practices and programs, which resulted in a Salmonella reduction to 0% by the fourth sampling month (P =.013). The satisfactory results strongly suggest that a multiple-intervention approach is crucial to improve food safety in this type of premises.Item Quantitative Bio-Mapping of Salmonella and Indicator Organisms at Different Stages in a Commercial Pork Processing Facility(2022) Bueno López, Rossy (TTU); Vargas, David A. (TTU); Jimenez, Reagan L. (TTU); Casas, Diego E. (TTU); Miller, Markus F. (TTU); Brashears, Mindy M. (TTU); Sanchez-Plata, Marcos X. (TTU)The purpose of this study was to develop a quantitative baseline of indicator organisms and Salmonella by bio-mapping throughout the processing chain from harvest to final product stages within a commercial conventional design pork processing establishment. Swab samples were taken on the harvest floor at different processing steps, gambrel table, after polisher, before final rinse, after the final rinse, post snap chill, and after peroxyacetic acid (PAA) application, while 2-pound product samples were collected for trim and ground samples. The samples were subjected to analysis for indicator microorganism enumeration, Aerobic Count (AC), Enterobacteriaceae (EB), and generic Escherichia coli (EC), with the BioMérieux TEMPO®. Salmonella prevalence and enumeration was evaluated using the BAX® System Real-Time Salmonella and the SalQuant™ methodology. Microbial counts were converted to Log Colony-forming units (CFU) on a per mL, per g or per sample basis, presented as LogCFU/mL, LogCFU/g and LogCFU/sample, prior to statistical analysis. All indicator microorganisms were significantly reduced at the harvest floor (p-value < 0.001), from gambrel table to after PAA cabinet location. The reduction at harvest was 2.27, 2.46 and 2.24 LogCFU/mL for AC, EB and EC, respectively. Trim sample values fluctuated based on cut, with the highest average AC count found at neck trim (2.83 LogCFU/g). Further process samples showed the highest AC count in sausage with a mean of 5.28 LogCFU/g. EB counts in sausage (3.19 LogCFU/g) showed an evident increase, compared to the reduction observed at the end of harvest and throughout trim processing. EC counts showed a similar trend to EB counts with the highest value found in sausage links (1.60 LogCFU/g). Statistical microbial process control (SPC) parameters were also developed for each of the indicator microorganisms, using the overall mean count ((Formula presented.)), the Lower control limit (LCL) and Upper control limit (UCL) at each sampling location. For Salmonella prevalence, a total of 125/650 samples were found positive (19%). From those positive samples, 47 samples (38%) were suitable for enumeration using the BAX® System SalQuant™, the majority detected at the gambrel table location. From those enumerable samples, 60% were estimated to be between 0.97 and 1.97 LogCFU/sample, while the rest (40%) were higher within the 2.00–4.02 LogCFU/sample range. This study provides evidence for the application of indicator and pathogen quantification methodologies for food safety management in commercial pork processing operations.Item The Effects of Castration, Implant Protocol, and Supplementation of Bos indicus-Influenced Beef Cattle under Tropical Savanna Conditions on Growth Performance, Carcass Characteristics, and Meat Quality(2022) Huerta-Leidenz, Nelson (TTU); Jerez-Timaure, Nancy; Rodas-González, Argenis; Sarturi, Jhones Onorino (TTU); Brashears, Mindy M. (TTU); Miller, Markus F. (TTU); Brashears, Michel Todd (TTU)The effects of castration, supplementation, and implant protocol (IP) on growth, carcass characteristics, and meat quality of grass-fed cattle were evaluated. Two experiments followed a two-way ANOVA and a 2 × 2 factorial arrangement. Experiment-I, 99 bulls were evaluated for: (a) supplementation (mineral (MS) or strategic protein-energy supplementation (SS)), and (b) IP (repeated (day-0 and day-90) Zeranol-72 mg implantation (Zeranol–Zeranol) or Trenbolone Acetate-140 mg/Estradiol-20 mg (day-0) followed by Zeranol-72 mg (day-90) (TBA/E2–Zeranol)). Experiment II, 50 animals were evaluated for: (a) IP (like Experiment-I), and (b) male class (steers vs. bulls). In Experiment-I, SS bulls had greater growth rate, carcass yield, and yield of high-valued boneless lean cuts than MS bulls, while decreasing (p < 0.05) time to harvest. Steaks from SS-bulls on TBA/E2– Zeranol IP were more (p = 0.05) tender than SS/Zeranol–Zeranol counterparts. Experiment-II bulls had greater growth than steers, but decreased (p < 0.05) carcass quality aspects. Zeranol–Zeranol increased (p <0.01) meat tenderness of steers. Interactions (p < 0.05) affected cutability (Experiment-II) and meat sensory traits (Experiment-I/II). The SS improved growth, carcass yield, and shortened days until harvest of bulls, while TBA/E2–Zeranol IP positively affected tenderness in bull meat only. Castration improved carcass quality while the implant effects on cutability and tenderness were male-class dependent.