Ultrasound Technology as Inactivation Method for Foodborne Pathogens: A Review

An efficient microbiological decontamination protocol is required to guarantee safe food products for the final consumer to avoid foodborne illnesses. Ultrasound and non-thermal technology combinations represent innovative methods adopted by the food industry for food preservation and safety. Ultrasound power is commonly used with a frequency between 20 and 100 kHz to obtain an “exploit cavitation effect”. Microbial inactivation via ultrasound derives from cell wall damage, the oxidation of intracellular amino acids and DNA changing material. As an inactivation method, it is evaluated alone and combined with other non-thermal technologies. The evidence shows that ultrasound is an important green technology that has a good decontamination effect and can improve the shelf-life of products. This review aims to describe the applicability of ultrasound in the food industry focusing on microbiological decontamination, reducing bacterial alterations caused by food spoilage strains and relative foodborne intoxication/infection.

Applications of ultrasound techniques in tandem with non-destructive approaches for the quality evaluation of edible oils

Edible oils include triglycerides that are extracted from oil seeds or fruits such as sunflowers, palms, olives, soys, rapeseeds, cocoa and many others. They are the elementary origins of unsaturated fats and vitamins especially vitamin 'E' in people's diets. Edible oils are at risk of intentional (such as inadequate storage conditions) and unintentional adulteration, so it is necessary to pay attention to their safety, health and fraud. Generally, this evaluation can be destructive or non-destructive. There are numerous methods to evaluate quality of edible oils which include sensory analysis, chemical analysis, chromatography, ultrasound, etc. The Ultrasonic approach is a non-destructive way and also fast, accurate, inexpensive, repeatable, portable and simple. Combination of ultrasound with other techniques such as electronic nose, electronic tongue, visible spectroscopic fingerprints, chemical descriptors, Raman spectroscopy, mid-infrared and machine vision, will improve quality evaluation and detection accuracy. This review summarizes the ultrasound idea and the latest knowledge of its application with other techniques on evaluation of edible oils.

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.

Phase separation technology based on ultrasonic standing waves: A review

The current understanding and developments of phase separation technology based on ultrasonic standing waves (USWs) are reviewed. Most previous reviews have focused on microscale applications of this technology in the fields of biological materials and food processing. This review covers different applications of ultrasonic separation technology, especially in petrochemical industry. The kinetic mechanism of ultrasonic, design of reactors, separation principles, and related applications are discussed in detail. We lay special stress on the motion characteristics of particles in USWs. According to the particle numbers, particle properties, and frequency characteristics, the separation principles are reasonably categorized as: (1) Bands effect; (2) Acoustophoretic coefficient; (3) Particle density; (4) Sweep frequency. Diverse separation principles improve the universality of ultrasonic separation technology. However, acoustic streaming and acoustic cavitation are two of the main challenges in the application of ultrasonic separation. Based on the current research, the future research can focus on the following aspects: (1) Explore the mechanism of ultrasonic demulsification; (2) Establish unified evaluation criteria for acoustic separation systems; (3) Develop the basis for determination of acoustic cavitation and non-cavitation.

Effect of Ultrasound Technology on Food and Nutritional Quality

Ultrasound technology has been successfully demonstrated for several food processing and preservation applications. The majority of food processing applications reported refer to liquid foods. Ultrasound has been applied to solid foods in some niche applications, e.g., tenderization of meat, mass transfer applications, and drying. Similar to any other technology, ultrasound also has some positive and negative effects on food quality depending on the application and processing conditions employed. This chapter outlines various applications of ultrasound to food and its effect on food and nutritional quality.

Extraction of olive oil assisted by high-frequency ultrasound standing waves

High-frequency ultrasound standing waves (megasonics) have been demonstrated to enhance oil separation in the palm oil process at an industrial level. This work investigated the application of megasonics in the olive oil process on laboratory and pilot scale levels. Sound pressure level and cavitational yield distribution were characterised with hydrophones and luminol to determine associated physical and sonochemical effects inside the reactor. The effect of water addition (0%, 15%, and 30%), megasonic power levels (0%, 50%, and 100%), and malaxation time (10min, 30min, and 50min) was evaluated using response surface methodology (RSM) in a 700g batch extraction process. The RSM showed that the effect of the megasonic treatment (585kHz) in the presence of a reflector is more prominent at longer malaxation time (50min) and at higher water addition (30%) levels post-malaxation. Longer megasonic treatment of the malaxed paste (up to 15min; 220kJ/kg) increased oil extractability by up to 3.2%. When treating the malaxed paste with the same specific energy, higher oil extractability was obtained with longer treatments and low megasonic power levels in comparison to higher power levels and shorter times. Megasonic treatment of the paste before malaxation (585kHz, 10min, 146kJ/kg) and no water addition provided an increase in oil extractability of up to 3.8% with respect to the non-sonicated control. A double sonication intervention, before and after malaxation, using low (40kHz) and high (585kHz) frequency, respectively, provided up to 2.4% increase in oil extractability. A megasonic intervention post-malaxation (400 and 600kHz, 57-67min, 18-21kJ/kg) on a pilot scale using early-harvest olive fruits resulted in up to 1.7% extra oil extractability. Oil extracted under a high sonication frequency (free radical production regime) did not impact on olive oil quality parameters at reactor characterisation levels. Megasonic standing wave forces can enhance olive oil separation at various stages of the olive oil extraction process.