Liana Drummond

Vacuum Cooling of Meat Products: Current State-of-the-Art Research Advances

Vacuum cooling (VC) is commonly applied for cooling of several foodstuffs, to provide exceptionally rapid cooling rates with low energy consumption and resulting in high-quality food products. However, for products such as meat and cooked meat products, the higher cooling loss of vacuum cooling compared with established methods still means lower yields, and important meat quality parameters can be negatively affected. Substantial efforts during the past ten years have aimed to improve the technology in order to offer the meat industry, especially the cooked meat industry, optimized production in terms of safety regulations and guidelines, as well as meat quality. This review presents and discusses recent VC developments directed to the cooked meat industry. The principles of VC, and the basis for improvements of this technology, are firstly discussed; future prospects for research and development in this area are later explored, particularly in relation to cooling of cooked meat and meat products.

Immersion vacuum cooling of cooked beef – Safety and process considerations regarding beef joint size

Cooked beef samples (1, 2, and 3kg; 4.7, 5.6, and 6.2cm average radius, respectively) were cooled from ∼72 to 4°C core temperature using either air blast (AB), immersion vacuum (IVC) or vacuum (VC) cooling. IVC cooled larger samples within 4h and took less than 2.5h between 72 and 10°C. IVC cooling times were on average shorter than AB and longer than VC for all sizes. Differences increased with size. IVC and AB cooling losses were comparable (P>0.05) while lower on average (P<0.05) than VC losses for same size samples. Additionally, samples between 1.0 and 4.3kg (4.2-8.7cm average radius) were cooled by either IVC or VC. Cooling times were between 2.8 and 5.5h for IVC and between 1.1 and 3.2h for VC. There was a significant effect (P<0.01) of sample size on IVC cooling times. Cooling profiles of larger samples were tested using USDA cooling growth model for Clostridium perfringens in beef broth. According to the model, none of the analyzed profiles would support significant growth of the bacteria.

Effects of processing parameters on immersion vacuum cooling time and physico-chemical properties of pork hams.

The effects of agitation (1002 rpm), different pressure reduction rates (60 and 100 mbar/min), as well as employing cold water with different initial temperatures (IWT: 7 and 20°C) on immersion vacuum cooling (IVC) of cooked pork hams were experimentally investigated. Final pork ham core temperature, cooling time, cooling loss, texture properties, colour and chemical composition were evaluated. The application for the first time of agitation during IVC substantially reduced the cooling time (47.39%) to 4.6°C, compared to IVC without agitation. For the different pressure drop rates, there was a trend that shorter IVC cooling times were achieved with lower cooling rate, although results were not statistically significant (P>0.05). For both IWTs tested, the same trend was observed: shorter cooling time and lower cooling loss were obtained under lower linear pressure drop rate of 60 mbar/min (not statistically significant, P>0.05). Compared to the reference cooling method (air blast cooling), IVC achieved higher cooling rates and better meat quality.

Temperature evolution and mass losses during immersion vacuum cooling of cooked beef joints - A finite difference model.

A finite difference model was developed to describe and predict the temperature and mass loss evolution in reconstructed beef joints during immersion vacuum cooling. Fast cooling is obtained within beef pores and at beef surface when evaporation in the surrounding liquid is high. The cooling rate diminishes as the vacuum chamber pressure stabilizes and the liquid temperature reaches its lower value. The maximum deviation between measured and calculated temperatures was within 5°C for the beef (core and surface) and within 7°C for the surrounding liquid (measured at the bottom of the container). Absolute differences between predicted and experimental mass losses for the liquid and beef sample were around 2% and 1%, respectively. Mass losses are higher during the first period when evaporation is the main mode of heat transfer. Mechanical agitation in the surrounding liquid is suggested as a way to further reduce cooling times and to prevent uneven cooling.

Vacuum Cooling of Foods

Abstract Vacuum cooling is a rapid evaporative cooling technique that is mainly achieved through evaporation of part of the moisture of the product under vacuum. The advantages of vacuum cooling include shorter processing time, extended product shelf life, and improved product quality and safety. These have consequently increased its popularity among food manufacturers and research scientists. Initially, this chapter outlines the principles and equipment of vacuum cooling. Further, it reviews the current status of vacuum cooling in various sectors of the food processing industry, including well-established commercial applications and recent advances of the process and equipment, research and development, and future prospects. The advantages and disadvantages of the technique compared with other cooling methods are also discussed, as well as factors that affect its performance.