Time matters when ultrasonicating beef: The best time for tenderness is not the best for reducing microbial counts

Abstract

Research on the effects of high‐intensity ultrasound (HIU) on meat quality properties shows contradictory results. The latter has been sometimes attributed to limited exposure time, not enough to cause cellular modifications. This study evaluated the effect of different exposure times (0, 10, 20, and 40 min) of HIU (37 kHz, 90 W cm−2) on physicochemical properties including; pH, color, tenderness, and microbial counts of two different portions of beef Longissimus lumborum (cranial–caudal). No significant effect of loin portion was observed (p > .05). Ultrasonication time caused a 20.7% toughness reduction of beef (p < .05). However, ultrasonication time also increased hue from 0.62 to 0.76 from red to orange values (p < .05), but it did not affect important coordinates such as a* or C*. Ultrasound caused an increase in the pH from 5.46 to 5.6 (p < .05), but pH was not affected by the time. The highest tenderness was achieved at 40 min of sonication. Significant reductions of mesophiles, psychrophiles, and coliforms were observed after ultrasonication when compared to control (p < .05). The best ultrasonic condition for microbial reduction was at 10 min, when the lowest microorganism counts were achieved, with a subsequent growth when increasing ultrasonication time. Practical Applications High‐intensity ultrasound application appears to be a promising method to increase tenderness in beef. However, optimum time, intensity, and methodology for its application have to be defined, because the variations may affect other quality characteristics such as color or microbial contamination. To find ideal parameter values may help the industry to take decisions on the design of specialized equipment for ultrasonication of meat.

Ultrasound for Meat Processing: Effects of Salt Reduction and Storage on Meat Quality Parameters

“…The microstructure of the meat samples before and after ultrasound-assisted brining was observed with a scanning electron microscope (SEM). The meat samples of size 1 × 1 × 0.25 cm were fixed in 3% glutaraldehyde for 1h; samples were dehydrated in a series of ethanol solutions (10,20,30,50,70, 90, 100%) and dried at critical point CO 2 (Critical Point Dryer (CPD) Quorum E3100, Quorum Technologies Ltd., Lewes, UK). Samples were observed under a Zeiss Ultra Plus Field Emission SEM (Carl Zeiss Ltd., Jena, Germany).…”

“…Similar observations were reported [49], where it was shown that low-frequency ultrasound (70 kHz) increased the growth rate of bacterial cells on polyethylene surface compared to growth without ultrasound; the authors suggested that by increasing the rate of transport of oxygen and nutrients to the cells, US processing could influence the growth of bacteria [49]. The authors reported that a treatment of 10 min was the best US condition (37 kHz, 90 W) to achieve microbial reduction in beef, while increased treatment time led to increased bacterial growth [50]. On the other hand, Kang et al [17] have reported a significant (p < 0.05) increase in E. coli cell numbers in beef samples after US processing, suggesting that extended ultrasound treatment could be needed to inactivate the microorganisms present on the meat surface.…”

Physicochemical characteristics and shelf life of beef treated with high‐intensity ultrasound

“…Physicochemical characteristics are major concerns in the meat industry as product acceptance levels by consumers is fully dependent on them (i.e., texture or tenderness, color, and juiciness (Grunert et al., 2004). The application of HIU in beef increases the tenderness (Alves et al., 2018; Chang et al., 2015; Diaz‐Almanza et al., 2019; Peña‐Gonzalez et al., 2017) and accelerates aging without negative impacts on other technological and sensory attributes (Peña‐Gonzalez et al., 2017). Enhanced tenderness values have been achieved at 40 min (37 kHz and 90 W/cm 2 ) of sonication (Diaz‐Almanza et al., 2019).…”

“…The application of HIU in beef increases the tenderness (Alves et al., 2018; Chang et al., 2015; Diaz‐Almanza et al., 2019; Peña‐Gonzalez et al., 2017) and accelerates aging without negative impacts on other technological and sensory attributes (Peña‐Gonzalez et al., 2017). Enhanced tenderness values have been achieved at 40 min (37 kHz and 90 W/cm 2 ) of sonication (Diaz‐Almanza et al., 2019). In addition US does not negatively affect color ( L *, a *, b *, C *), but increases hue values (Carrillo‐Lopez, Luna‐Rodriguez, et al., 2019; Diaz‐Almanza et al., 2019).…”

“…Enhanced tenderness values have been achieved at 40 min (37 kHz and 90 W/cm 2 ) of sonication (Diaz‐Almanza et al., 2019). In addition US does not negatively affect color ( L *, a *, b *, C *), but increases hue values (Carrillo‐Lopez, Luna‐Rodriguez, et al., 2019; Diaz‐Almanza et al., 2019). HIU also decreases pH (Carrillo‐Lopez, Luna‐Rodriguez, et al., 2019; Carrillo‐Lopez, Huerta‐Jimenez, et al., 2019) and improves the water‐holding capacity of meat (Carrillo‐Lopez, Huerta‐Jimenez, et al., 2019; Stadnik et al, 2008).…”