Temperatures and ages of packs of beef displayed at stores in Canada

The surface temperatures and ages of 1703 retail packs of chilled, raw beef in cut or ground forms on display in a case at each of 41 Canadian retail stores were determined. For each case, data were collected from packs at pre-selected positions in the case. Data for a position were not collected if a pack of beef was not present there. Data were collected at a different time on each of 3 days, with each store being visited within l h after opening and l h before closing and between 12:00 and 14:00 h, without regard to the operation of the case defrosting cycle. The median temperatures of pack surfaces were <4?°C, between 4 and 7?°C, and >7?°C at 24, 16 and one stores, respectively. The maximum temperatures were <4?°C, between 4 and 7?°C and >7?°C at 3, 18, and 20 stores, respectively. The median ages were 0 day, 1 day, and 2 or 3 days at 19, 17 and 5 stores, respectively. The maximum ages were ?2 days, between 2 and 4 days, and >4 days at 21, 14 and six stores, respectively. Temperatures were generally lower at the backs than at the fronts of cases, on upper than on bottom shelves, and within than on the tops of stacks of packs. Temperatures were apparently not affected by the positions of packs along the lengths of cases, and did not differ at different times of day.     

Consumer acceptability and physiochemical characteristics of modified atmosphere packed beef steaks

The objective of this study was to investigate the physiochemical changes of beef steaks packed under various combinations of gasses and the relationship between consumer perception of flavour and acceptability of modified atmosphere packed beef steaks during retail display. Experimental gas atmospheres included: 40%, 50%, 60%, 70%, and 80% oxygen, with all packs containing 20% CO₂ and the make up gas N₂. Steaks were stored at 4 °C for 12 days and tested for lipid and protein oxidation, heme iron, colour, oxymyoglobin concentration, Warner–Bratzler shear force (WBSF) and consumer acceptability for the resulting cooked meat. The results from 134 consumers indicated a directional preference for the steaks stored in packs containing 40% and 80% oxygen. Samples with high oxygen levels, particularly the O₂60 and O₂70 treatments, were positively and significantly (P < 0.01) correlated to sensory toughness, and significantly (P < 0.05) negatively correlated to juiciness, as determined by consumers. However, the O₂40 samples were most negatively (P < 0.001) correlated to toughness and positively (P < 0.01) correlated to juiciness, which shows that, in general, these higher O₂ levels, >40%, imparted greater meat toughness as determined by the consumers. The greater directional acceptance of the O₂40 samples may be linked to the consumer perceived reduction in sensory toughness and increases in juiciness.     

Scandinavian consumer preference for beef steaks packed with or without oxygen

Beef steaks retail-packed with (80% O₂, 20% CO₂) or without oxygen (either skin-packed or gas-packed (69.6% N₂, 30% CO₂, 0.04% CO or 70% N₂, 30% CO₂)) were compared by consumers in Denmark (n = 382), Norway (n = 316) and Sweden (n = 374). Two pairs of two steaks – one steak packed in a high oxygen atmosphere and one packed without oxygen – were given to the consumers. They were instructed to prepare the steaks at home on two consecutive days, and two persons had to taste each steak. In Denmark, the oxygen-free packing was either gas packing with CO (69.6% N₂, 30% CO₂, 0.04% CO) or without CO (70% N₂, 30% CO₂), in Norway it was either gas packing with CO (69.6% N₂, 30% CO₂, 0.04% CO) or skin packing, and in Sweden it was either skin packing or gas packing without CO (70% N₂, 30% CO₂). The meat represented animals that were between 17 and 80 months old (Denmark) and young bulls (Norway and Sweden).     

Carbon dioxide flavour taint in modified atmosphere packed beef steaks

The objective of this study was to investigate the effects of carbon dioxide (CO₂) concentration (100mlCO₂/100 ml pack gas, 50mlO₂:20mlCO₂:30mlN₂/100 ml pack gas, 70mlO₂:30mlCO₂/100 ml pack gas and 80mlO₂:20mlCO₂/100 ml pack gas) on the sensory quality of modified atmosphere packed (MAP) beef steaks (M. longissimus thorasis). Steaks were stored at 4 °C for 15 days and tested for CO₂ off flavour, lipid oxidation flavour, juiciness and tenderness (up to day 12) of the resulting cooked meat as well as pH, colour, drip loss, and cooking loss. One steak from each of the experimental treatments was taken immediately from the respective MA packs and cooked before serving straight to panellists. A second steak from each of the pack was treated similarly, but left in ambient air for 30 min to let dissolved CO₂ dissipate from the meat prior to cooking and serving. The 50mlO₂:20mlCO₂:30mlN₂/100 ml pack gas treatment displayed a significantly (P ≤ 0.05) and negative correlation to CO₂ flavour which was even more pronounced for samples where the CO₂ was allowed to dissipate (Dis, P ≤ 0.001). Thus this packaging gas combination could be used to optimise the sensory quality of MAP steak. Additionally opening retail MAP packs up to 30 min prior to cooking has a benefit towards the perceived sensory quality of the cooked product.     

Sensory comparison of commercial low and high oxygen modified atmosphere packed sirloin beef steaks

The objectives of this study were to investigate the effects of using commercially low and high modified atmosphere packaging (MAP) on quality characteristics of sirloin beef steaks. Gas mixtures used included 80% O₂:20% CO₂ (O₂80), 70% O₂/30% CO₂ (O₂70) and 50% O₂/30% CO₂:20% N₂ (O₂50) and for commercial packs O₂75 ± 5%, CO₂25 ± 5%, < 5% N₂-(O₂Com). All samples were packed in similar tray and packaging film formats. The experimental parameters monitored included microbiological, physiochemical and sensory measurements (naïve assessors). Microbial counts did not exceed the recommended legal ranges over the storage period. However the numbers of LAB (lactic acid bacteria) were the highest for commercially-packed samples (O₂Com) in comparison to laboratory packaged samples (O₂80, O₂70 and O₂50). Commercially-packaged samples eventually spoiled due to the occurrence of off-flavours and off-odours and subsequently were the least acceptable to sensory naïve assessors.     

The effect of family beef taboos on beef consumption on young Taiwanese adults

A family tradition of beef taboos exists in Chinese societies. The marketplace for beef in Taiwan is imported mainly from the U.S., Australia, and New Zealand. For mechanised-farming families or even for those no longer engaged in agriculture, beef consumption is often not encouraged nor allowed by family members. Using quantitative data in the analyses, this study was undertaken to examine whether family beef taboos influenced beef consumption for young adults in Taiwan. Respondents from beef-consuming families consumed more beef (4.34 times/week: average, 150.07 g/week: cooked) than respondents from non-beef-consuming families (1.87 times/week: average, 56.67 g/week: cooked). For the respondents from non-beef-consuming families, spiritual burden was a main factor affecting their own beef consumption. The implications based on this study’s findings are provided.     

Effects of oxygen concentration on the sensory evaluation and quality indicators of beef muscle packed under modified atmosphere

Beef steaks are commonly displayed under high oxygen concentrations in modified atmosphere packs (MAP) in order to promote colour stability. Such conditions, however, may also cause quality deterioration through lipid oxidation and decreased tenderness. The objective of this study was to investigate the effects of oxygen concentration (0%, 10%, 20%, 50% and 80%) on the quality of MAP beef steaks (M. longissimus dorsi). Steaks were stored at 4°C for 15 days and tested for lipid and protein oxidation, heme iron, colour, oxymyoglobin concentration, tenderness and sensory acceptability (up to day 12) for the resulting cooked meat. Sensory panellists expressed a preference for steaks stored in packs containing 50% oxygen, despite detecting oxidised flavours under these conditions. This could be the result of adaptation to, or familiarity with, oxidised flavours by panellists.     

Physicochemical and sensory properties of restructured beef steaks containing beef heart surimi

Summary Restructured beef steaks containing beef heart surimi were prepared. Changes in flavour, texture, thiobarbituric acid-reactive substances (TBARS), and compression force of the restructured steaks were evaluated after frozen storage (−29 °C) for 1, 30, and 90 days. Incorporation of propyl gallate-washed beef heart surimi improved the steak flavour score by 7%, texture score by 30%, and cooking yield by 4%, compared to non-surimi control steaks. Addition of water-washed surimi (without propyl gallate) also improved physical properties of restructured steaks, but it induced off-flavour and rancidity development.     

Prevalence of Shiga toxin-producing Escherichia coli in beef

Over the past two decades, many human illness outbreaks were attributed to consumption of undercooked beef products containing Shiga toxin-producing Escherichia coli (STEC). The illnesses included mild or bloody diarrhea, hemorrhagic colitis, and the life-threatening hemolytic uremic syndrome (HUS). Tracing these outbreaks to O157 and an increasing number of non-O157 STEC strains suggests that beef safety concerns will continue to rise and may negatively affect the beef industry. To effectively address these concerns, it is critical to evaluate the role of beef in STEC infections. In this review, published reports on beef contamination were evaluated to assess prevalence rates and health risks of STEC isolates. Global testing of beef showed wide ranges of prevalence rates of O157 (from 0.01% to 54.2%) and non-O157 (from 1.7% to 62.5%) STEC. Of the 155 STEC serotypes found in beef, 31 and 25 are known to cause HUS and/or other illnesses, respectively.     

Effects of breed and a concentrate or grass silage diet on beef quality in cattle of 3 ages. II: Meat stability and flavour

This study examined the effect of breed and diet on meat quality, defined as lipid stability, colour shelf life and sensory quality. Ninety-six steers were used, half Aberdeen Angus (AA) cross and half Holstein-Friesian (HF). They were reared from 6 months of age on a standard concentrate diet or grass silage and slaughtered at 14, 19 or 24 months of age. Breed had small effects on quality with lower lipid stability in muscle of 24 month-old HF (P<0.05). Sensory scores were similar between the breeds, the few differences being in favour of AA. Diet had the biggest effects on meat quality, in all 3 age groups. The grass silage diet produced higher plasma and muscle levels of vitamin E, lower lipid oxidation in loin steaks measured at 4 and 7 days of retail display and better colour stability (saturation) during shelf life in MAP (O(2):CO(2); 75:25) (all P<0.001). The high values for lipid oxidation in the concentrate-fed steers were linked to high muscle PUFA concentrations and low levels of vitamin E.     

Listeria monocytogenes: Occurrence in beef and identification of the main contamination points in processing plants

This study aimed to establish the occurrence of Listeria spp., especially L. monocytogenes and its main serotypes, in beef and processing plants. A total of 443 samples were obtained from equipment, installations and products from 11 meat processing establishments from Paraná state, Brazil. All samples were analyzed using USDA methodology for Listeria spp. detection, followed by species identification. The occurrence of Listeria spp. in the samples was 38.1% of which 51.4% were from equipment, 35.4% from installations and 30.2% from products. The identified species were: L. monocytogenes (12.6%), L. innocua (78.4%), L. seeligeri (1.2%), L. welshimeri (7.2%) and L. grayi (0.6%). The identified serotypes of L. monocytogenes were 1/2a and 4b. The results demonstrate the significance of equipment and installations as sources of contamination by Listeria spp. and L. monocytogenes in the processing of beef and meat products.     

Moisture sorption isotherm of fresh lean beef and external beef fat

The moisture sorption isotherm (MSI) of lean beef and fat beef was experimentally determined. The experimental procedure used was that of the COST 90 project with some modifications to accelerate equilibration. The procedure was validated with the standard reference material microcrystalline cellulose. The MSI of the beef at the highest humidity range was obtained by accelerating equilibration with changes of salts, using a low water activity salt for some time. This procedure was reliable for beef samples but not for the fat samples. No significant changes were found for lean beef in the temperature range 5–40 °C. Three models, GAB, Peleg and Lewicki, were used to fit the experimental data. The best fit was obtained with the GAB equation. The fat MSI was determined at 5, 15 and 25 °C and it was best fitted with the Lewicki model.     

Antioxidative activity of carnosine in gamma irradiated ground beef and beef patties

The activity of carnosine as a natural antioxidant in gamma irradiated ground beef and beef patties was studied. Samples of ground beef, in the absence and presence of 0.5% or 1.0% carnosine, as well as raw and cooked beef patties prepared with 1.5% salt (NaCl), in the absence and presence of 0.5% or 1.0% carnosine, were gamma irradiated at doses of 0, 2, and 4 kGy. The extent of oxidation in irradiated and non-irradiated samples of ground beef and raw beef patties was then determined during refrigerated (4 ± 1 °C) and frozen (−18 °C) storage, while determined for cooked beef patties during refrigerated storage only. Moreover, the determination of metmyoglobin (MetMb) accumulation and sensory evaluation for the visual color were carried out for samples of ground beef and raw patties. The results indicated that salt or salt and cooking accelerated the oxidative processes and significantly increased the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in the prepared non-irradiated samples. However, salt slowed down the accumulation of MetMb in raw patties. Irradiation treatments and storage in the absence of carnosine significantly (P < 0.05) increased the PV and TBARS in samples, at higher rates in salted or salted and cooked beef. Moreover, irradiation and storage significantly (P < 0.05) increased the formation of MetMb in ground beef and raw patties in the absence of carnosine. Addition of carnosine significantly (P < 0.05) reduced the oxidative processes and MetMb formation (proportionally to the used concentration) in samples post-irradiation and during storage. Furthermore, carnosine exerted significant efficacy in maintaining an acceptable visual red color post-irradiation and during storage of ground beef and raw patties. These results demonstrate that carnosine can be successfully used as a natural antioxidant to increase the oxidative stability in gamma irradiated raw and cooked meat products.     

Quality and bacteriological consequences of beef carcass spray-chilling: Effects of spray duration and boxed beef storage temperature

The effects of water spray-chilling on beef carcass traits and muscle quality, bacteriology and retail case life were determined in a research abattoir. Chilling treatments were compared using 10 crossbred steer carcasses (280 ± 4 kg) at each spray duration (4, 8, 12 and 16 h) and each vacuum storage temperature (1, 4, 8 and 12 °C). Control sides were air-chilled (1 °C, 24 h) while spray-chilled sides were sprayed with an intermittent water mist at 1 °C in four, 60 s cycles/h for the initial 4-16 h of chilling. The effects of storage temperature were evaluated using vacuum packaged longissimus thoracis (LT) muscle at post-chill intervals of 2, 16, 30 and 44 days. Chilling treatment effects were similar at all spray-chill durations and LT vacuum storage times and temperatures. Carcass spray-chilling did not effect pH, lean colour, % moisture, sarcomere length, shear value or weight loss during the vacuum storage of LT muscle. Carcass fat colour tended to brighten as spray duration was extended up to 12 h, but there was a grey discoloration of fat at spray durations beyond 12 h. Chilling treatment had only marginal effects on anaerobic bacteria during the vacuum storage of LT muscles, or aerobic bacteria during the retail display of rib-eye steaks, and the retail case life of steaks was largely unaffected by spray-chilling. A linear relationship between spray-chill duration and carcass weight loss was determined and carcass shrinkage was reduced by 0.08 g/100 g for every hour of spray-chilling. It was estimated that a major beef processing abattoir could utilize spray-chilling to save more than 2000 kg daily in carcass shrinkage, without compromising quality or increasing spoilage losses.     

Factors associated with surface iridescence in fresh beef

The objective of this study was to investigate factors associated with surface iridescence in fresh beef. Eight muscles were evaluated for occurrence of surface iridescence: Biceps femoris (BF), Gluteus medius (GM), Longissimus lumborum (LD), Psoas major (PM), Rectus femoris (RF), Semimembranosus (SM), Semitendinosus (ST), and Tensor fasciae latae (TF). Incidence of surface iridescence was 91% for ST, 34% for SM, 27% for LD, 20% for GM, 12% for RF, 9% for BF, 8% for TF, and 6% for PM (P<0.05). Factors associated with surface iridescence in the ST were further examined because iridescence was observed to a much higher degree in the ST as compared with other muscles evaluated. Greater ST surface iridescence was associated with larger ribeye areas, more youthful lean maturity scores, higher L^*, a^* and b^* colorimeter values, lower ultimate pH values, and faster cooking (P<0.05).     

牛肉肠褪色反应机制及控制

对牛肉肠易氧化褪色的原因进行了研究，认为牛肉自身色素蛋白含量高及产品不饱和脂肪酸含量高，是造成牛肉肠易褪色的主要原因。同时，提出了用切断油脂自动氧化的链锁反应、螯合金属离子、调整ｐＨ值、减少氧化残留量等措施，来延缓产品褪色反应的进行。     

Performance of cold-set binding agents in re-formed beef steaks

Four cold-setting gel-forming binding agents were compared in preparation of re-formed steaks from strips of each of two muscles, M. triceps brachii-caput longum (TB) from the shoulder, and M. pectoralis profundus (PP) from the brisket, of steer forequarter. The binding agents, which were commercial preparations, were Activa, containing transglutaminase enzyme as active ingredient, Fibrimex, containing the blood plasma fractions fibrinogen and thrombin, Textor, containing a modified starch, and alginate, containing sodium alginate and Ca⁺⁺. Binding of the cooked steaks and of slices therefrom, was satisfactory for the first three of the above but relatively weak for the alginate agent. Colour of steaks was affected by binder, in that Activa and Textor treatments gave lighter, redder and yellower (higher L∗, a∗, b∗ values) steaks than did the other two. Overall acceptability ratings by taste panels corresponded with those for flavour in the case of TB steaks, with Activa and Fibrimex samples scoring highest (P < 0.05). For the less tender PP steaks, the highest acceptability score was for the Textor samples, reflecting their scoring best for tenderness. Warner–Bratzler shear force values corresponded with tenderness ratings in that Textor samples had lowest shear values for both muscles, but the differences were not significant. The overall conclusion, considering cohesion, appearance, cooking yield and sensory quality of the products, was that the Activa binder performed best and would facilitate the production of good-quality chilled re-formed beef steaks from various low-value beef muscles, and without addition of sodium chloride if so desired.     

Stratification of toughness in beef roasts

Most meat scientists adopt a reductionist approach to the study of meat toughness, taking a few intramuscular cores from one or more muscles to simplify the enormous complexity of toughness in all the retail cuts derived from a whole carcass. This is a valid approach to a complex problem, but we should also start to consider how consumers respond to bulk meat such as steaks and roasts. Probing whole roasts reveals a complex internal structure, detectable by both connective tissue fluorescence and resistance to penetration. The dorsal aponeurosis of the Longissimus thoracis is a major connective tissue stratum in beef rib roasts and its properties are correlated with those of adjacent intramuscular connective tissues. When the aponeurosis is cooked, its reflectance first increases with protein denaturation, then decreases with gelatinisation. Heat-induced contraction is concurrent with the increase in reflectance. Gelatinisation is reduced if the aponeurosis is mechanically restrained to resist contraction. Thus, mechanical restraint interacts with heat penetration in explaining stratification of toughness in bulk meat.     

Evaluation of a dehydrated beef protein to replace sodium-based phosphates in injected beef strip loins

A dehydrated beef protein (DBP) was evaluated as a replacement for the phosphate added to beef injection brines. U.S. Select strip loins (n=20) were injected to 110% of their initial weight with a brine containing 3.6% salt and 4.5% sodium phosphate (CON) or 3.6% salt and 5% dehydrated beef protein (DBP). DBP loins had less fluid loss after 30 min. Steaks from both treatments lost similar amounts of fluid during storage. Total fluid loss was lower for DBP injected product. Lipid oxidation (TBARS) products were 0.23-0.60 mg/Kg higher for DBP steaks. DBP steaks were slightly less red than CON steaks according to instrumental measurements. Sensory panel evaluation, however, indicated no differences in redness. DBP steaks were less tender according to trained sensory panel. Results indicated the DBP to be effective in increasing brine retention and a viable alternative to phosphates when used in brines injected into beef strip steaks.     

Demographics and beef preferences affect consumer motivation for purchasing fresh beef steaks and roasts

Surveys completed by 1370 consumers determined the motivational factors affecting consumer purchasing decisions for fresh beef steaks and roasts in three regions in the United States. Females placed greater importance on tenderness, ease of preparation, and nutritional value of steaks and roasts when compared to males. Age influenced tenderness, product consistency, and nutritional value of steaks, but influenced flavor, product consistency, and nutritional value of roasts. Consumers felt juiciness, nutritional value, and natural products were less important in determining their purchasing choices of steaks and roasts as their level of education increased. The preferred degree of doneness of steaks influenced the value placed on six of the nine purchasing motivators. Beef preferences and demographics influenced consumer purchasing decisions for fresh beef steaks and roasts. Results from this study can be used to help identify factors to positively influence purchasing decisions within targeted market segments.