Nätprovfisket i Vättern 2023

Sötvattenslaboratoriet vid institutionen för akvatiska resurser, SLU Aqua, genomförde sommaren 2023 ett nätprovfiske i Vättern. Provfisket är en del av övervakningsprogrammet för Hjälmaren, Mälaren, Vänern och Vättern, som SLU Aqua utför och är datavärd för. Provfisket genomfördes med bottensatta översiktsnät av typen 'Stora sjöarna' (Bss) mellan 2023-07-17 och 2023-08-10. De lokaler som provfiskades var Fingals, Norrgrundet, Kråk/Flisen, Tängan och Lakaskär. Väderförhållandena under provfisket var mycket dåliga, vilket ledde till att 5 nät inte kunde läggas och att 3 nät var tvungna att flyttas från planerad plats. Totalt fångades 12 arter i provfisket varav sik var den dominerande arten sett till både antal och vikt. Fångstutvecklingen analyserades för förändringar över tid med avseende på antalet fångade individer och deras längdfördelningar. Mellan åren 2005 och 2023 har antal och vikt per ansträngning ökat av lake, sik och röding, medan gers har minskat. Öringen har ökat i antal men ökningen i vikt är inte statistiskt säkerställd. Abborrens längd har ökat och gersens längd har minskat

Towards sustainable onion storage

Onion is an important component of the diets of many cultures worldwide, and also one of the most commonly produced vegetables. The onion bulb is a well-adapted storage organ and many of the harvested bulbs are stored for several months to ensure year-round availability to consumers. However, significant amounts are lost due to sprouting, loss of water, loss of dry matter, fungal infections and bacterial infections. To optimise storage and enable sales at the correct point in time to reduce losses decision support systems are needed to identify signs of quality problems. One potential such system is the monitoring of volatile organic compounds in the air of storage facilities to detect developing quality problems, such as storage diseases. In this thesis, the volatile organic compounds emanating into the headspace of onion bulbs affected by Fusarium basal plate rot, Penicillium rot or Pectobacterium-caused soft rot were investigated. The aim was to identify the compounds that are relevant as indicators of developing storage diseases, and which could be the target of future monitoring systems. Several relevant indicator compounds were found. Some of them are naturally occurring onion metabolites whose relative abundance changed, including methyl propyl disulfide and dimethyl disulfide. Others, such as ethenylbenzene and 2,3-butanediol are products typical of fungal or bacterial metabolism. Other systems for storage monitoring may include physiological measurements to predict quality changes such as sprouting. Therefore, the thesis also investigated the connection between selected physiological indicators and sprouting. It was found that the changing concentrations of glucose, fructose and sucrose, and the decreasing dry matter contents of the bulbs had a significant connection to the start of sprouting

Maleimide grafting onto polysaccharides via mild condition esterification and its impact on their structure

This study proposes an innovative approach to tailor the properties of two polysaccharides, microcrystalline cellulose (MCC) and potato starch, through chemical modification in dispersion. The methodology involves the grafting of 6-Maleimidohexanoic acid (6-MHA) moieties onto hydroxyl groups of the polysaccharides without dissolving them in order to keep their native structure preserved. To overcome the slow and inefficient reaction between carboxylic acids of 6-MHA and hydroxyl groups of the polysaccharides, a vinyl ester of 6-MHA was synthesized through the transvinylation of 6-MHA acid with vinyl acetate. The resulting 6-MHA ester was employed to introduce a new functionality to polysaccharides’ hydroxyl groups via transesterification, catalyzed by potassium carbonate. To enhance the reactivity, the polysaccharides were mercerized prior to modification process. The efficiency of the transesterification reaction between the vinyl ester of 6-MHA and the hydroxyl groups of the polysaccharides was confirmed using Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Thermal behavior analysis was carried out using thermogravimetric analysis (TGA), while changes in crystallinity resulting from the modification were assessed through X-ray diffraction analysis (XRD). Finally, the impact of the modification on the morphology of polysaccharides was examined with environmental scanning electron microscopy (ESEM). Despite changes in microstructure, MCC kept its macrostructure remained morphologically unchanged while the granular structure of starch was damaged. Maleimide grafting onto MCC and starch has the potential to turn them into thermally reversible materials for various applications such as debondable adhesive or coating

Occurrence of Campylobacter, Listeria monocytogenes, and extended-spectrum beta-lactamase Escherichia coli in slaughterhouses before and after cleaning and disinfection

To prevent foodborne illness, adequate cleaning and disinfection (C&D) is essential to remove pathogenic bacteria from the slaughter environment. The aim of this study was to determine the presence of Campylobacter spp., Listeria monocytogenes, and extended-spectrum beta-lactamase-producing Escherichia coli (ESBL E. coli) before and after C&D in slaughterhouses. Samples from food- and non-food contact surfaces taken before and after C&D in one red meat and one poultry slaughterhouse were analyzed for the target bacteria. Whole-genome sequencing and antimicrobial susceptibility testing were performed. In total, 484 samples were analyzed. Campylobacter spp. were isolated from 13.0% to 15.5% of samples before C&D in the red meat and poultry slaughterhouse, respectively. Listeria monocytogenes was isolated before C&D in 12.5% and 5.2% of samples in the red meat and poultry slaughterhouse, respectively. It was noted that C. jejuni was detected on multiple surfaces and that L. monocytogenes showed potential persistence in one slaughterhouse. After C&D, L. monocytogenes was found in one sample. ESBL E. coli was not detected either before or after C&D. These findings show the possibility to remove pathogenic bacteria from slaughter and meat processing facilities, but also indicate that deficiencies in slaughter hygiene pose a risk of cross-contamination of meat

Voluntary biodiversity credits

Biodiversity is rapidly declining worldwide, which threatens ecosystems that provide support for food production, clean water, and climate stability. A major challenge to protecting biodiversity is that there is insufficient funding for nature conservation and restoration. Approximately 30% of the global land area is covered by forests used for wood production. In Sweden and other European countries, these production forests are economically important and present valuable opportunities for biodiversity preservation, restoration, and sustainable management. However, without viable economic incentives that stewards how to best balance productivity with ecological integrity, declines in biodiversity will likely persist. Biodiversity credits are an innovative financial tool that can compensate private forest owners for their contributions to biodiversity enhancement to address funding gaps and encourage participation in conservation initiatives. By purchasing biodiversity credits, companies can fund initiatives such as forest restoration, habitat protection, and species conservation. This thesis reviewed biodiversity credits as a market-based mechanism to incentivize conservation and restoration efforts in production forests in a manner that aligns with policies such as the EU Nature Restoration Law. Clear regulatory frameworks and reliable verification systems are needed for biodiversity credit implementation to be successful. However, biodiversity credit design still needs to be optimized to sufficiently balance conservation, carbon sequestration, and wood production. Creation of a well-structured biodiversity credit market will allow Sweden and the EU to make nature conservation a financially viable and scalable solution to ensure that forests remain productive while retaining their rich biodiversity

Prevalence and Severity of Pale, Soft, and Exudative (PSE)-like zones in crossbred pigs (Hampshire x Yorkshire): Insights into Season, Gender, Slaughter weight and Technological Meat Traits

Pale, soft, and exudative (PSE)-like zones in pork is a growing concern, affecting several meat quality attributes as well as production economics. This study investigates the prevalence and severity of PSE-like zones in Swedish commercial crossbred pigs (Yorkshire dam x Hampshire sire), focusing on the effects of the key factors such as season, gender, slaughter weight and technological meat quality traits. A total of 192 pigs were sampled during four seasons (autumn, winter, spring, summer) and assessed for post-slaughter PSE-like zones. Results revealed that season significantly influenced the prevalence of PSE-like zones, with a notably lower prevalence observed in summer compared to other seasons. Gender differences were also significant, with female pigs showing a higher incidence of PSE-like zones compared to immuno-castrated males. Additionally, slaughter weight was significantly associated with the prevalence of PSE-like zones, while the proportion of affected muscle weight notably influenced severity levels. Among technological meat quality traits, lightness (L*) and yellowness (b*) showed strong associations with both prevalence and severity, while redness (a*) demonstrated a significant association solely with severity. Additionally, ultimate temperature (Temp24h) had a significant effect on prevalence of PSE-like zones. These findings underscore the importance of season-specific environmental management and handling practices to minimize the prevalence and severity of PSE-like zones. Future strategies integrating genetic selection, stress reduction measures, and optimized slaughter processes hold potential for improving meat quality outcomes in commercial pork production systems

Alternative domestic rodent pest management approaches to address the hazardous use of metal phosphides in low- and middle-income countries

Metal phosphides, particularly aluminium phosphide (AlP) and zinc phosphide (Zn3P2), are widely used in low- and middle-income countries (LMICs) as rodenticides in urban and domestic environments due to their low cost and high toxicity to rodent pests. However, they are also highly toxic to humans with no antidote available and have been associated with numerous fatal cases of intentional and accidental poisoning. This paper reviews alternatives to metal phosphide use for rodent pest management in urban and domestic environments, highlights case studies of effective alternative approaches, and provides recommendations for research and policy. This review identifies numerous alternative methods available for managing rodent pests in domestic/urban settings that can replace metal phosphides. These include chemical methods, i.e. rodenticides, and non-chemical methods, e.g. rodent-proofing, sanitation and trapping. However, because the majority of chemical rodenticides qualify as highly hazardous pesticides due to acute human health toxicity, environmental toxicity, and/or bioaccumulation, simply selecting substitute chemical rodenticides to replace metal phosphides are likely to replace one set of hazards with others. Thus, careful risk and hazard assessments are needed when considering substituting with other chemicals. Overall, we need to move away from current levels of rodenticide reliance towards more integrated and ecologically based approaches

“It is not a complicated question but it is very complex” – Insights on school ground greening from practitioners

School ground vegetation supports children’s health, learning, and ecosystems but faces challenges in implementation and management, with limited research addressing the entire greening process. This study investigates what green practitioners in Sweden experience as challenges when implementing and managing school ground vegetation. Expert interviews were conducted with 26 experienced practitioners and revealed issues across the implementation chain. Challenges were categorized into direct and indirect factors. Direct factors included practical concerns such as avoiding monocultures, preventing soil compaction, and differing opinions on species selection, planting size, fencing, and managing children’s movement. Indirect factors focused on lack of knowledge of either the benefits of vegetation or what is needed for its establishment among the actors surrounding the respondents. Using the Policy Arrangement Approach, the study analysed how actors, rules, resources, and discourses shape implementation. The analysis highlighted the significance of regulations and the need for increased knowledge of both outdoor pedagogy and vegetation requirements

Mellangrödor efter stärkelsevete som förfrukt till sockerbetor – försök på Kronoslätt

Syftet med fältförsöken på Kronoslätt, 2018-2021, var att undersöka om eftersådda sommarmellangrödor, sådda i mitten av augusti, och etablerade efter skörd av stärkelsevete, kan vara lämpliga förfrukter till sockerbetor. Särskilt fokus låg på att identifiera alternativa mellangrödor till oljerättika i växtföljder med raps eller andra kålväxter. Vi utvärderade om honungsört, blodklöver, bovete och purrhavre kunde bidra till en förbättrad ekonomi i sockerbetsodlingen, god ogräskontroll, ökad markkolsinbindning och nematodkontroll, när mellangrödorna odlades som förfrukt.Resultaten visar att ogödslade mellangrödor, särskilt renbestånd av honungsört samt en blandning av honungsört och blodklöver, kan vara intressanta alternativ. Dessa två framstår även som ekonomiskt fördelaktiga, jämfört med att odla sockerbetor med oljerättika som förfrukt på en lättlera och i en växtföljd med sockerbetor, korn, höstraps och höstvete. I jämförelse med oljerättika så tyder försöken på att de ogödslade mellangrödorna honungsört samt blandningen av honungsört och blodklöver, i snitt över tre år, kan ge ett ökat ekonomiskt netto för sockerbetorna, på ca 750 resp. ca 1400 kr/ha och år, när stöd erhålls för odling av mellangrödorna (11 SEK/€)