Properties of Oaxaca Cheese Elaborated with Ultrasound-Treated Raw Milk: Physicochemical and Microbiological Parameters.

The effect of ultrasound-treated fresh raw milk upon yield, physicochemical and microbiological quality of Oaxaca cheese was evaluated under a factorial design. The ultrasound frequencies tested were 25 and 45 kHz, during 15 or 30 min. The cheeses made with the ultrasonicated milk (30 min, high-intensity ultrasound, HIU) had greater luminosity without significant changes in hue or chroma, as compared to the controls with no HIU. The yield improved significantly (by up to 2.8 kg/100 L of milk), as the ultrasound treatment time increased. Such cheese yield is attributable to the higher protein content, which was up to 1.5% higher, after sonication. Long-treatment time (30 min) at 25 kHz significantly lowered mesophilic bacteria counts down to limits allowed by current regulations and favors the growth of lactic acid bacteria (LAB) while lowering mold and yeast counts. The absence of E. coli and Salmonella spp. and the decrease in S. aureus counts in Oaxaca cheese were attributed to the mixing of the paste with hot water, inherent to the traditional elaboration process, and to the antagonistic effect of the ultrasound-triggered increased LAB on pathogenic bacteria. Since the artisanal elaboration of Oaxaca cheese does not comply with the current Mexican regulations regarding mesophiles, ultrasound could be a suitable technology to protect its genuine elaboration process with raw milk.

The Physicochemical, Microbiological, and Structural Changes in Beef Are Dependent on the Ultrasound System, Time, and One-Side Exposition.

The effect of high-intensity ultrasound (HIU) system (bath, 37 kHz and 90 W/cm2; or probe, 24 kHz and 400 W) and application time (25 or 50 min, one-side exposition) on the properties of bovine Longissimus lumborum after 7 d of storage at 4 °C was studied. The bath system significantly increased the lightness of the muscle, while other color parameters (a*, b*, hue, and chroma) were not different from the control. The water holding capacity and shear force decreased significantly (3.1-5% and 0.59-0.72 kgf, respectively) in sonicated meat independently of the system, favoring the tenderization of the muscle after storage. Microstructural changes observed in the HIU-exposed surface provided evidence of a higher area of interfibrillar spaces (1813 vs. 705 µm2 in the control), producing tenderization of the muscle, compared with the control. HIU significantly increased counts of total aerobic and coliform bacteria, especially after 50 min of ultrasonication. HIU also increased lactic acid bacterial counts in the bath system. Single-sided muscle exposition to ultrasound may produce sufficient significant changes in muscle properties, which could decrease long treatment times that would be needed for the exposition of both sides. HIU in bath systems increases tenderness by modifying meat ultrastructure, with no significant changes in physicochemical parameters. Nevertheless, microbiological quality may need to be considered during the process due to a slight increase in bacterial counts.

Post-mortem ultrasound and freezing of rabbit meat: Effects on the physicochemical quality and weight loss.

High intensity ultrasound (HIU) is a technique with the potential to improve meat quality, however, more research is needed on its application within the chain of cold storage and freezing. This study evaluates the effect of HIU (40 kHz, 9.6 W/cm2, 20 and 40 min) and post-mortem development on the yield and physicochemical quality of rabbit meat in samples treated with HIU pre- and post-storage in a freezer (120 h at -20 °C). Twenty rabbit carcasses were vacuum packed 12 h post-mortem, placed in a fridge at 4 °C for 24 h, and divided in two groups (HIU application before or after freezing), before assigning the treatments. The results show that HIU before freezing produced intense and bright orange-yellow colours, whereas its application after freezing resulted in pale red tones. HIU application accelerates rigor mortis resolution when it is applied before freezing and causes a significant decrease in pH immediately following the HIU treatment. Post-freezing application of HIU is not recommended because it considerably increased weight loss and toughening of the meat when long exposure times were used (40 min). In contrast, a short treatment duration with HIU mitigated the effects of freezing and produced significant increases in water-holding capacity (WHC) after cold storage. The yield (weight loss) of the rabbit meat was not affected when HIU was applied pre-freezing. The application of HIU pre-freezing constitutes a promising technology because it increased the tenderness and the WHC of rabbit meat. However, more research is needed to improve the appearance before scaling up to industrial levels.

High-Frequency Focused Ultrasound on Quality Traits of Bovine Triceps brachii Muscle.

This aim of this study was to evaluate the effect of high-frequency focused ultrasound (HFFU) on quality traits of bovine Triceps brachii. Four treatments (0, 10, 20, and 30 min) of HFFU (2 MHz and 1.5 W/cm2) were applied to bovine T. brachii muscle. Immediately after treatment, evaluations of color, pH, drip loss, water holding capacity, and shear force in meat were undertaken. The application of HFFU slightly decreased (p < 0.05) the redness of meat. In addition, a significant (p < 0.05) decrease in the shear force of meat was observed after the application of HFFU at 30 min. No effect (p > 0.05) was observed on other color parameters, drip loss, and water holding capacity of meat. Overall, HFFU improved beef tenderness without negative impacts on color, pH, drip loss, and water holding capacity of meat. HFFU offers the option of tenderizing specific muscles or anatomical regions of the beef carcass. These findings provide new insights into the potential application of ultrasound in meat processing.

Recent advances in the application of ultrasound in dairy products: Effect on functional, physical, chemical, microbiological and sensory properties.

Alternative methods for improving traditional food processing have increased in the last decades. Additionally, the development of novel dairy products is gaining importance due to an increased consumer demand for palatable, healthy, and minimally processed products. Ultrasonic processing or sonication is a promising alternative technology in the food industry as it has potential to improve the technological and functional properties of milk and dairy products. This review presents a detailed summary of the latest research on the impact of high-intensity ultrasound techniques in dairy processing. It explores the ways in which ultrasound has been employed to enhance milk properties and processes of interest to the dairy industry, such as homogenization, emulsification, yogurt and fermented beverages production, and food safety. Special emphasis has been given to ultrasonic effects on milk components; fermentation and spoilage by microorganisms; and the technological, functional, and sensory properties of dairy foods. Several current and potential applications of ultrasound as a processing technique in milk applications are also discussed in this review.

To Provide a Double Feeder in Growing Pigs Housed under High Environmental Temperatures Reduces Social Interactions but Does Not Improve Weight Gains.

Heat stress and competition for food are two major challenges in pigs reared in intensive conditions. The aim of the present work was to study the effect of providing a double feeder for pigs reared under two different environmental temperatures. In addition, two types of flooring, of 100% slat and 30% slat 70% concrete, were also considered. A total of 256 pigs in the growing-finishing period (from 27 kg to 110 kg) were housed using two environmental temperatures: control (from 18 °C to 25 °C) and heat stress (above 30 °C six hours a day). They were housed in 32 pens of 8 pigs each, distributed into 4 rooms (16 with one feeder and 16 with two). Pigs subjected to temperatures above 30 °C up to six hours had lower body weight gains than pigs subjected to a maximum temperature of 25 °C, confirming that thermal stress negatively affects performance in pigs. In addition, heat stress affected the final product by decreasing the lean percentage of carcasses by 2.6%. A double feeder reduced the presence of negative social behavior, especially in the feeding area, but body weight was lower than when one single feeder was used. A 30% slat 70% concrete floor showed better results in the pig stress indicators and body weights than 100% slat. It is concluded that providing a double feeder in the pens, although reducing the presence of negative social interactions, negatively affected body weight, in comparison to pigs fed with just one feeder.

Natural Oregano Essential Oil May Replace Antibiotics in Lamb Diets: Effects on Meat Quality.

A study was conducted to investigate the effect of oregano essential oil (OEO) and monensin sodium on the oxidative stability, colour, texture, and the fatty acid profile of lamb meat (m. Longissimus lumborum). Twenty Dorper x Pelibuey lambs were randomly divided into five treatments; control (CON), monensin sodium (SM, Rumensin 200® 33 mg/kg), a low level of OEO (LO, 0.2 g/kg dry matter (DM)), a medium level of OEO (MO, 0.3g/ kg DM), and a high level of OEO (HO, 0.4 g/kg DM). Dietary supplementation of OEO at any concentration lowered the compression strength in comparison with CON and SM. MO had the highest a* values (7.99) and fatty acid concentration (C16:1n7, C18:1n9c, C18:1n6c, C20:1n9, and C18:2n6c) during storage for 7 d at 3 °C. Lipid oxidation was not promoted (p > 0.05) by the moderated supplementation of oregano essential oil; however, OEO at 0.3 g/kg DM showed a slight lipid pro-oxidant effect. Dietary supplementation of MO and SM had the same effect on colour, tenderness, and the fatty acid profile of lamb (L. lumborum). It was demonstrated that oregano essential oil was beneficial for lambs feeding, and it could be a natural alternative to replace monensin in lamb diets with improvements in the quality of the meat.

The Effect of High-Intensity Ultrasound on the Physicochemical and Microbiological Properties of Mexican Panela Cheese.

High-intensity ultrasound could be an alternative to pasteurization for cheeses made with fresh raw milk, the properties of which must be preserved as part of their intangible cultural heritage, such as Panela cheese in Mexico. This research aimed to study the effect of the amplitude (50% and 100%) and application time (0, 5, and 10 min) of ultrasound treatment of fresh raw milk, on the yield and microbiological and physicochemical qualities of Panela cheese after 24 h of storage at 4 °C. The yield was increased to 24.29% with 10 min of ultrasonication, although the amount of exudate was higher in the ultrasonic product than in the control (20.33%). As the ultrasonication time increased, the yellowness (b*) increased significantly, while the hue angle decreased (with values close to 90°), resulting in evident yellow tones in cheeses made with milk treated for 10 min. The pH significantly increased from 6.6 to 6.74 with 5 min of ultrasound, but decreased to 6.37 with 10 min of ultrasonication. Although no significant differences were found in fat content, the protein significantly increased with 5 min of sonication, but it decreased markedly when ultrasound was applied for 10 min. Ultrasound treatment with amplitudes of 50% effectively decreased the counts of coliform bacteria regardless of ultrasonication time. However, the mesophilic bacteria increased by a 0.9 log with an amplitude of 100% and 10 min treatment. The results showed that ultrasound improved the yield and microbial, nutritional, and physicochemical properties of Panela cheese.

High-intensity ultrasound applied on cured pork: Sensory and physicochemical characteristics.

This research aimed to evaluate the physicochemical characteristics and their relationship with sensory properties of cured porcine m. longissimus lumborum assisted by high-intensity ultrasound (HIU, 37 kHz, 22 Wcm-2). An experiment was designed with three factors at two levels each: type of curing (immersion or ultrasound-assisted -UA-), immersion time (30 or 90 min), and steak thickness (1.27 or 2.54 cm). After treatment and 7 days of storage at 4°C, the percentage of salt, pH, CIE L* a* b* color, water holding capacity (WHC), and shear force were determined in the samples. A quantitative descriptive analysis was performed using eight trained panelists. The HIU significantly increased the percentage of NaCl (p < .0005) and decreased the color saturation of the meat (p < .05), but did not affect the luminosity, redness (a*), yellowness (b*), pH, WHC, or shear force (all p > .05). The thickness of the steak had significant effects on almost all of the evaluated variables. Samples with 1.27 cm thickness had lower shear force, higher WHC and salt percentage (p < .0001). In agreement with this, the sensory profiles showed that the 1.27 cm samples treated with HIU for 30 min were perceived as less tough (more tender) and juicier.

Does ultrasound equally improve the quality of beef? An insight into longissimus lumborum, infraspinatus and cleidooccipitalis.

Quality of bovine longissimus lumborum, infraspinatus and cleidooccipitalis muscles after high-intensity ultrasound (HIU; 40 kHz and a power of 11 W/cm2 for 0, 40, 60, and 80 min) and aging (0, 7 and 14 d) was evaluated. The effects of HIU on pH and color of meat were not considered negative. HIU improved water holding capacity (WHC) of l.lumborum and infraspinatus only after aging. Whereas, the WHC of cleidooccipitalis increased immediately after sonication. The total collagen of HIU treated samples was significantly lower compared to the untreated samples. Ultrasonication for 80 min was the most effective for infraspinatus and cleidooccipitalis. Toughness decreased with HIU, iii nfraspinatus and l.lumborum tenderized more than cleidooccipitalis. HIU application and 7 d aging is an excellent combined treatment to improve tenderness of the three muscles. Infraspinatus was the most tender meat. HIU could help industry to improve the quality of beef as it helps in tenderization and accelerates maduration particularly of l.lumborum.

Bacterial control and structural and physicochemical modification of bovine Longissimus dorsi by ultrasound.

A multifactorial study to evaluate the effect of three ultrasound intensities (16, 28 and 90 Wcm-2), two sonication times (20 and 40 min), and two storage times (0 and 7 days at 4 °C) on physicochemical properties, microbiological counts, and microstructure of bovine Longissimus dorsi was performed. The results showed that ultrasound (US) did not modify luminosity (P = 0.42), redness (a*, P = 0.45), or yellowness (b*, P = 0.94). However, the hue angle increased with US treatment and during storage (P = 0.04), showing an important degradation in the color of meat treated with 16 Wcm-2. The pH and shear force decreased during storage at 4 °C (P = 0.01). Although US did not have any significant effects on the tenderness of the meat, the interfibrillar areas increased drastically in samples treated with 16, 28 and 90 Wcm-2 (P < 0.0001). US was effective in controlling mesophilic and psychrophilic bacteria during storage at 4 °C when intensities of 90 Wcm-2 were used (P < 0.0001), whereas decontamination of coliform bacteria was efficient independently of ultrasonication intensity, as long as a long sonication time (40 min) was used.

Ultrasound and meat quality: A review.

High intensity ultrasound (HIU) offers an alternative to traditional methods of food preservation, and is regarded as a green and promising emerging technology. Ultrasound generates acoustic cavitation in a liquid medium, developing physical forces that are considered the main mechanism responsible for changes in exposed materials. In meat, ultrasound has been successfully used to improve processes such as mass transfer and marination, tenderization of meat and inactivation of microorganisms. It is also an alternative to traditional meat ageing methods for improving the quality properties of meat. Moreover, the combination of ultrasonic energy with a sanitizing agent can improve the effect of microbial reduction in foods. This review describes recent potential applications of ultrasound in meat systems, as well as physical and chemical effects of ultrasound treatment on the conservation and modification of processed meat foods. Finally, the ultrasound application parameters must be deep explored and established before the method can be scaled to industrial levels.

Ultrasound as a potential process to tenderize beef: Sensory and technological parameters.

In this study, the effects of high intensity ultrasound (HIU), applied after storage, on the physical, microstructural, and sensory characteristics of beef were evaluated. Samples of four beef m. Longissimus dorsi muscle were stored in vacuum at 4 °C for 0, 7 or 14 days and then ultrasonicated (40 kHz, 11 W/cm2) for 60 min. Beef stored for 7 d prior to ultrasonication displayed increased pH and luminosity, reduced redness and saturation value, higher hue angle, and variable changes in water holding capacity. Shear force of sonicated meat was lower than that of control samples at all storage times. HIU also increased the tenderness and fragmentation of meat (P < 0.05) measured by texture profile analysis. The microstructure of sonicated meat showed a visible reduction in the size of fascicles, greater interfibrillary spaces, and thinner endomysium. These effects were enhanced with the storage of meat previous to HIU treatment. Meat stored for 14 d and then treated with ultrasound was perceived to have a more intense fresh meat smell and oily flavor (P < 0.05). However, it was also perceived to be a paler grayish brown color compared to control samples stored for the same duration. Ultrasonicated meat also presented a greater intensity of metallic taste (P < 0.05) and a more tender and moist texture (P < 0.05). Overall, application of HIU of meat after meat was stored affects textural and microstructural properties and accelerates aging without negative impacts on other technological and sensory attributes. Therefore, HIU application after storage has potential as a safe method for tenderizing bovine meat when handled under the conditions in this study.

Estrés oxidativo y el uso de antioxidantes en animales domésticos / Oxidative stress and the use of antioxidants in domestic animals

Los radicales libres o especies reactivas al oxigeno (ROS) se producen continuamente en el organismo como consecuencia de los procesos metabólicos normales y fuentes exógenas como el ejercicio intenso, situaciones de estrés, factores ambientales y agentes contaminantes (drogas y pesticidas). Un radical libre es una molécula o átomo que presenta al menos un electrón no apareado. Cuando la producción de ROS es excesiva, el resultado es el estrés oxidativo, término que se relaciona con el daño a las biomoléculas: proteínas, lípidos, carbohidratos y ADN. Asi mismo, se le ha relacionado con enfermedades que afectan a humanos y animales. La presente revisión tiene como objetivo revisar aspectos básicos del estrés oxidativo, así como la utilización de antioxidantes en las diferentes especies de animales domésticos