Lingonberry is a common wild berry that is often sold as jams and beverages. It naturally contains high amounts of the weak acid preservative benzoic acid making it an interesting ingredient for shelf-life extension. Despite this, their use as a raw ingredient is limited by the inherently intense sour taste. This study aimed to improve the taste of lingonberry juice by subjecting it to malolactic fermentation in order to reduce the sourness, and to investigate the benzoic acid in lingonberries as a natural preservative in juice blends by determining the microbial stability. After initial screening of lactic acid bacteria, a Lactiplantibacillus plantarum strain was used as the starter for subsequent investigations. Upon raising the pH, all malic acid was completely converted to lactic acid after seven days. The fermented juice was mixed with blackcurrant juice in different proportions. Challenge tests of the blends showed Listeria monocytogenes could not grow in any juice samples, while Candida albicans only grew in the pure blackcurrant juice. Aspergillus brasiliensis growth was delayed in all samples containing benzoic acid in a concentration-dependent manner. The sourness and astringency were substantially reduced in the juice with added L. plantarum compared to the unfermented juice. © 2024 The Authors

Bilberries (Vaccinium myrtillus) are the most common wild berries in Northern Europe. A substantial amount of the berries are picked with the objective to extract highly valued products such as anthocyanins. A smaller amount of the bilberries is used to make jams and drinks, and these are generally restricted to the domestic market. One reason is the sour taste, partly as a result of the high content of malic acid. By using certain strains of lactic acid bacteria with the ability to convert malic acid to lactic acid, the taste is predicted to be more pleasant. This process is called malolactic fermentation, and historically it has mostly been used in winemaking. After testing five different starter cultures, we identified that the strain, Lactiplantibacillus plantarum LP58, can rapidly convert malic acid to lactic acid without any loss of sugar or citric acid, which strongly indicates a successful malolactic acid fermentation. As it has been reported that other strains of L. plantarum can be used as biopreservative agents, the resulting product was also tested in terms of microbial safety after prolonged storage, and by means of metagenome sequencing. The obtained product was quite tolerant to microbial growth, but this observation was rather due to an initial heat treatment than the addition of lactobacilli. Potentially, starter cultures with documented biopreservative activity can be combined with L. plantarum LP58 to obtain a more stable product. Until then, the fermented bilberry juice must be processed and preserved like non-fermented bilberry products. © 2023, The Author(s).

Lingonberry is a popular fruit in the Nordic countries, where many variations of lingonberryproducts are available. The berry naturally contains high amounts of antioxidants andantimicrobial substances which make it an ideal natural preservative. The jui ce of lingonberryis also naturally low in pH which is often perceived as too sour in taste. To better utiliselingonberry juices as themselves or in combination with other ingredients, transformation ofthe juices is required to improve the palatability. The current study explored the possibility ofconverting malic to lactic acid using lactic acid bacteria, determine the changes in sensorycharacteristics of the fermented juices as well as blends thereof with blackcurrant juice, andinvestigate the microb ial stability of the juices when challenge tested. Lingonberries werepressed and the juices were fermented with L. plantarum. In order for the fermentation to beunimpeded due to active benzoic acid and successfully complete the conversion from malicacid to lactic acid, the pH of lingonberry juice was increased from 3.0 to 5.2. The resulting pHafter fermentation had stabilised to 4.9 after 7 days.To prepare the fermented lingonberry juices in a context of a mixture of juices, fermentedjuices were pasteurised and prepared in blends with diluted blackcurrant juice (25%) in fivedifferent proportions of lingonberry/blackcurrant juice; 0/100, 25/75, 5 0/50, 75/25, and 100/0.These five juices were evaluated with a sensory panel using descriptive analysis, along with anon fermented lingonberry juice. The juices evaluated showed that fermentation significantlyp <0.001) reduced the perceived sourness and astringency, seen from the difference betweenfermented and non fermented lingonberry juices. The fermentation had also significantlyp <0.001) increased the perceived sweetness of the juices.The five blends were also subjected to challenge tests using three microbial speciescommonly found in juices. In none of the samples the bacterium Listeria monocytogenes wereable to grow likely due to the low pH (3.07 4.98) possibly in combination with benzoic acid.The yeast, Candida albicans were only able to grow in 0/100 lingonberry/blackcurrant juice,which did not contain any benzoic acid. When testing Aspergillus brasiliensis, full growthcould only be observed in 0/100 lingonberry/blackcurrant j uice. In the blends, mould growthswere delayed in a concentration dependent manner where no growth was observed in the 100% fermented lingonberry juice even after six weeks. The challenge test overall indicated thatblends containing lingonberry juice pr event fungal growth although a high concentrationmight be required to prevent mold growth.

Cleaning, cleanliness, and hygiene are all undeniably central factors in human well-being, impacting both sensory experiences and the mitigation of infection spread. With the ongoing societal shift towards increased digitalization and automation, there is a growing interest in leveraging technology to rationalize and improve cleaning processes. Cleaning management systems utilizing connected sensors have emerged to optimize cleaning schedules in diverse settings such as restaurants, healthcare facilities, offices, shops, warehouses, and public spaces. This literature review report explores the vast landscape of publications addressing the topic of sensors that may provide viable data for decision-making algorithms in cleaning management systems. It also includes a few illustrating examples of commercially available sensors, as well as a list of some cleaning management systems on the market that employ sensors and data. Such systems may for instance exploit consumption data, detect visitor presence, and are often utilizing gas sensors. Gas sensors, being able to measure air quality, are maybe of particular interest for improving cleaning of restrooms. Some may be able to detect pure gases (like carbon dioxide), some react to several gases, and some are able to capture complex odours. Literature indicates that advancements in nano materials will likely lead to stable, energy-efficient gas sensors with increased sensitivity and selectivity. Electronic noses, arrays of gas sensors trained by algorithms, enable detection of complex odours and may enhance the selectivity of gas sensors. However, challenges persist, urging the need for continued improvement in gas sensor technology and smell sensing solutions, especially if to be integrated into Internet of Things (IoT) solutions. The review outlines various principles underlying gas sensors, emphasizing the preference for stable, low-energy technologies in IoT applications. While chemiresistive sensors exhibit promise, historical limitations in their sensitivity and selectivity have led to preferring other principles for certain applications, such as non-dispersive infrared and photoacoustic spectroscopy sensors. The review also describes technologies available for detecting other phenomena, including optical, ultrasound, and radar sensors. It is also underscored the potential in combining multiple sensor technologies to comprehensively assess soiling, tailored to specific environmental contexts. Despite significant progress, literature indicates that much work remains to fully exploit the capabilities of these integrated techniques for timely and efficient cleaning in diverse settings.

The cultivation of brown macroalgae, such as Laminaria ssp. and Saccharina latissima, has increased extensively during the last decades; according to a report by Food and Agriculture Organisation of the United Nations1 , the cultivation of brown seaweeds exceeded 16 M tons worldwide as per 2019. At the Swedish West coast, the most cultivated brown alga is S. latissima – Sugar kelp – and it is mainly produced for food purposes. The S. latissima body consists of a blade, a stipe and a holdfast. The holdfast and stipe are stiff and tough and not useful for food in its raw state; instead, they become a side stream in the production. Fermentation of the stipes and holdfasts could be a way of improving their food properties, but the traditionally used and food-safe microorganisms employed for fermentation of soybeans, cereals, and other plant-based substrates are adapted to grow on plant carbohydrates such as starch and cellulose. This could be an obstacle when attempting to use algae as a substrate, since they are mainly constituted of other carbohydrates, such as alginate, laminarin, fucoidan and mannitol. For fungi to grow on algal biomass there should be a need for enzymes that can degrade the algal carbohydrates to release sugar units to be taken up by the fungal cells, but we did not find any reports on known food-safe fungi specialized on algae. Therefore, we wanted to test different pre-treatments, with the aim to make the algal carbohydrates accessible for established and safe fungi, traditionally used for fermentation of plant material, so that they would be able to ferment the algal biomass. Our project aimed at assessing the feasibility of using side streams (stipes and holdfasts) from S. latissima as a substrate for solid-state fermentation and to make initial total protein analyses of the product. The goal was to present a proof-of-concept – a model product – for future studies of e.g. amino acid composition, nutritional value, bioavailability, sensorics and environmental impact. The long-term impact target was to enable sustainable and profitable valorization of a presently unused side stream.