Effect of the Application of Ultrasound to Homogenize Milk and the Subsequent Pasteurization by Pulsed Electric Field, High Hydrostatic Pressure, and Microwaves.

The efficacy of applying ultrasound (US) as a system to homogenize emulsions has been widely demonstrated. However, research has not yet shown whether the effect achieved by homogenizing milk with US is modified by subsequent pasteurization treatments that use new processing technologies such as pulsed electric fields (PEF), microwaves (MW), and high hydrostatic pressure (HPP). The aim of this study was, therefore, to optimize the application of US for milk homogenization and to evaluate the effect of PEF, HPP, and MW pasteurization treatments on the sensorial, rheological, and microbiological properties of milk throughout its shelf life. To homogenize whole milk, a continuous US system (20 kHz, 0.204 kJ/mL, 100%, 40 °C) was used, and different ultrasonic intensities (0.25, 0.5, and 1.0 kJ/mL) were evaluated. The optimal ultrasonic treatment was selected on the basis of fat globule size distribution and pasteurization treatments by MW (5800 W, 1.8 L/min), PEF (120 kJ/kg, 20 kV/cm) and HPP (600 MPa, 2 min, 10 °C) was applied. The ultrasound intensity that achieved the highest reduction in fat globule size (0.22 ± 0.02 µm) and the most homogeneous distribution was 1.0 kJ/mL. Fat globule size was smaller than in commercial milk (82% of volume < 0.5 µm for US milk versus 97% of volume < 1.2 µm for commercial milk). That size was maintained after the application of the different pasteurization treatments, and the resulting milk had better emulsion stability than commercial milk. After 28 days of storage, no differences in viscosity (4.4-4.9 mPa s) were observed. HPP pasteurization had the greatest impact on color, leading to higher yellowness values than commercial milk. Microbial counts did not vary significantly after 28 days of storage, with counts below 102 CFU/mL for samples incubated at 15 °C and at 37 °C. In summary, the homogenization of milk obtained by US was not affected by subsequent pasteurization processes, regardless of the technology applied (MW, PEF, or HPP). Further research is needed to evaluate these procedures' effect on milk's nutritional and functional properties.

Microbiological Food Safety of Seaweeds.

The use of seaweeds in the human diet has a long history in Asia and has now been increasing also in the western world. Concurrent with this trend, there is a corresponding increase in cultivation and harvesting for commercial production. Edible seaweed is a heterogenous product category including species within the green, red, and brown macroalgae. Moreover, the species are utilized on their own or in combinatorial food products, eaten fresh or processed by a variety of technologies. The present review summarizes available literature with respect to microbiological food safety and quality of seaweed food products, including processing and other factors controlling these parameters, and emerging trends to improve on the safety, utilization, quality, and storability of seaweeds. The over- or misuse of antimicrobials and the concurrent development of antimicrobial resistance (AMR) in bacteria is a current worldwide health concern. The role of seaweeds in the development of AMR and the spread of antimicrobial resistance genes is an underexplored field of research and is discussed in that context. Legislation and guidelines relevant to edible seaweed are also discussed.

Saccharina latissima Cultivated in Northern Norway: Reduction of Potentially Toxic Elements during Processing in Relation to Cultivation Depth.

There is an increasing interest in the use of Saccharina latissima (sugar kelp) as food, but the high iodine content in raw sugar kelp limits the daily recommended intake to relatively low levels. Processing strategies for iodine reduction are therefore needed. Boiling may reduce the iodine content effectively, but not predictably, since reductions from 38-94% have been reported. Thus, more information on which factors affect the reduction of iodine are needed. In this paper, sugar kelp cultivated at different depths were rinsed and boiled, to assess the effect of cultivation depth on the removal efficacy of potentially toxic elements (PTEs), especially iodine, cadmium, and arsenic, during processing. Raw kelp cultivated at 9 m contained significantly more iodine than kelp cultivated at 1 m, but the difference disappeared after processing. Furthermore, the content of cadmium and arsenic was not significantly affected by cultivation depth. The average reduction during rinsing and boiling was 85% for iodine and 43% for arsenic, but no significant amount of cadmium, lead, or mercury was removed. Cultivation depths determined the relative effect of processing on the iodine content, with a higher reduction for kelp cultivated at 9 m (87%) compared to 1 m (82%). When not taken into consideration, cultivation depth could mask small reductions in iodine content during rinsing or washing. Furthermore, since the final content of PTEs was not dependent on the cultivation depth, the type and extent of processing determines whether cultivation depth should be considered as a factor in cultivation infrastructure design and implementation, or alternatively, in product segmentation.

Assessment of Food Quality and Safety of Cultivated Macroalgae.

Macroalgae aquaculture is 16 times larger than fish on a mass basis, making macroalgae by far the largest group of aquacultured products [...].

Valorization of Tomato Surplus and Waste Fractions: A Case Study Using Norway, Belgium, Poland, and Turkey as Examples.

There is a large potential in Europe for valorization in the vegetable food supply chain. For example, there is occasionally overproduction of tomatoes for fresh consumption, and a fraction of the production is unsuited for fresh consumption sale (unacceptable color, shape, maturity, lesions, etc.). In countries where the facilities and infrastructure for tomato processing is lacking, these tomatoes are normally destroyed, used as landfilling or animal feed, and represent an economic loss for producers and negative environmental impact. Likewise, there is also a potential in the tomato processing industry to valorize side streams and reduce waste. The present paper provides an overview of tomato production in Europe and the strategies employed for processing and valorization of tomato side streams and waste fractions. Special emphasis is put on the four tomato-producing countries Norway, Belgium, Poland, and Turkey. These countries are very different regards for example their climatic preconditions for tomato production and volumes produced, and represent the extremes among European tomato producing countries. Postharvest treatments and applications for optimized harvest time and improved storage for premium raw material quality are discussed, as well as novel, sustainable processing technologies for minimum waste and side stream valorization. Preservation and enrichment of lycopene, the primary health promoting agent and sales argument, is reviewed in detail. The European volume of tomato postharvest wastage is estimated at >3 million metric tons per year. Together, the optimization of harvesting time and preprocessing storage conditions and sustainable food processing technologies, coupled with stabilization and valorization of processing by-products and side streams, can significantly contribute to the valorization of this underutilized biomass.

Assessment of food quality and microbial safety of brown macroalgae (Alaria esculenta and Saccharina latissima).

BACKGROUND: There has been a rapid increase in the number of seaweed farms in the Western world, and it is crucial for these companies and their customers to have standardized methods for quality assessment and optimization. The aim of this study was to adapt known methods for food-quality determination for the analysis of seaweed quality, including color, texture, and microbiology, and to discuss optimal heat treatments for the popular macroalgae Saccharina latissima and Alaria esculenta. RESULTS: The development of an attractive, green color during heating was highly specific to species, freezing history, and part of the thallus. Resilience and thermostability were also species dependent. Low microbial numbers (1-3 log cfu/g) for total aerobic count, psychrotrophic bacteria, and spore-forming bacteria were found, but Bacillus spp. were isolated. No enterococci, coliforms, pathogenic vibrios, or Listeria monocytogenes were detected. CONCLUSION: The methods employed were able to describe clearly the physical and microbial qualities of A. esculenta and S. latissima, and quality changes during processing. Based on the results, optimal cooking for a minimum of 15 min at 95 °C was suggested for S. latissima. Fresh and frozen A. esculenta showed the greenest color after heating for 5-9 s at a high temperature (> 85 °C). If a higher heat load is needed to achieve safe and stable food products, using fresh and not frozen A. esculenta is highly recommended, as fresh specimens remain green even after 15 min at 95 °C. © 2018 Society of Chemical Industry.

Comparative Evaluation on the Quality and Shelf life of Atlantic Salmon (Salmo salar L.) Filets Using Microwave and Conventional Pasteurization in Combination with Novel Packaging Methods.

A comparative evaluation on the effect of carbon dioxide (CO2 ) on quality and shelf life of Atlantic salmon loins pasteurized with microwave and conventional technology was conducted. The experimental design allowed CO2 to enter the salmon muscle before (soluble gas stabilization [SGS] + vacuum) or after pasteurization (CO2 emitter + vacuum), whereas the control samples (vacuum only) were not presented for CO2 . This setup resulted in six different groups; three heated with microwaves and three with conventional pasteurization. The core temperature of microwave samples was 58.8 ± 2.2 °C, whereas the surface temperature was equal to the oven temperature (62 °C) during conventional pasteurization and close to the core temperature during microwave pasteurization (57.6 ± 1.4 °C). Microwave-heated samples showed higher microbial growth; decreased shelf life; and darker (lower L* -value), more reddish (higher a* -value), and yellowish (higher b* -value) colors compared to conventional-heated salmon. Lowest liquid loss (LL) was observed in salmon packaged with the CO2 emitter, whereas a SGS step prior to pasteurization did not affect the LL negatively as compared to samples packaged in vacuum only. Treatment with CO2 , independent of the prestep using SGS or an emitter, resulted in increased shelf life. Protein denaturation, microbial growth, product color, product shelf life, and sensory properties of the salmon loin were significantly affected by the applied pasteurization method (microwave- or conventional pasteurization). However, the heat load was probably too high to detect differences resulting from the pretreatment using SGS or packaging with CO2 emitter. PRACTICAL APPLICATION: Recent developments with increased time pressure from both work and past time activities have led to a tremendous increase in the demand for convenient, tasty ready-to-use food options. Furthermore, contemporary trends for consumption of fresh or lightly processed seafood stress the need to develop processing methods that allow a fulfillment of these demands, while still offering a reasonable shelf life. Carbon dioxide in combination with either microwave or conventional pasteurization is innovative processing technology that can meet consumer's demand of such products.

Change in the color of heat-treated, vacuum-packed broccoli stems and florets during storage: effects of process conditions and modeling by an artificial neural network.

BACKGROUND: Vacuum-packed broccoli stems and florets were subjected to heat treatment (60-99 °C) for various time intervals. The activity of peroxidase was measured after processing. Thermally processed samples were then stored at 4 °C for 35 days, and the color of the samples was measured every 7 days. Effects of parameters (heating temperature and duration, storage time) on the color of broccoli were modeled and simulated by an artificial neural network (ANN). RESULTS: Simulations confirmed that stems were predicted to be more prone to changes than florets. More color loss was observed with longer processing or storage combinations. The simulations also confirmed that higher temperatures during heat processing could retard color changes during storage. For stems treated at 80 °C for short durations, color loss was more predominant than both 65 and 99 °C, probably due to the incomplete inactivation of enzymes besides more tissue damage, with increased enzyme access to the substrate. CONCLUSION: The greenness of both stems and florets during storage can be better preserved at higher temperatures (99 °C) and short times. The simulation results revealed that the ANN method could be used as an effective tool for predicting and analyzing the color values of heat-treated broccoli. © 2018 Society of Chemical Industry.