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Wood is a hygroscopic material that absorbs and desorbs water to equilibrate to the ambient climate. Within material science, the moisture range from 0 to about 95–98% relative humidity is generally called the hygroscopic moisture range, while the exceeding moisture range is called the over-hygroscopic moisture range. For wood, the dominating mechanisms of moisture sorption are different in these two moisture ranges; in the hygroscopic range, water is primarily bound by hydrogen bonding in cell walls, and, in the over-hygroscopic range, water uptake mainly occurs via capillary condensation outside cell walls in macro voids such as cell lumina and pit chambers. Since large volumes of water can be taken up here, the moisture content in the over-hygroscopic range increases extensively in a very narrow relative humidity range. The over-hygroscopic range is particularly relevant for durability applications since fungal degradation occurs primarily in this moisture range. This review describes the mechanisms behind moisture sorption in the over-hygroscopic moisture range, methods that can be used to study the interactions between wood and water at these high humidity levels, and the current state of knowledge on interactions between modified wood and water. A lack of studies on interactions between modified wood and water in the over-hygroscopic range was identified, and the possibility of combining different methods to acquire information on amount, state, and location of water in modified wood at several well-defined high moisture states was pointed out. Since water potential is an important parameter for fungal growth, such studies could possibly give important clues concerning the mechanisms behind the increased resistance to degradation obtained by wood modification.

Moisture plays a central role in the performance of wood products because it affects important material properties such as the resistance to decomposition, the mechanical properties, and the dimensions. To improve wood performance, a wide range of wood modification techniques that alter the wood chemistry in various ways have been described in the literature. Typically, these modifications aim to improve resistance to decomposition, dimensional stability, or, to introduce novel functionalities in the wood. However, wood modification techniques can also be an important tool to improve our understanding of the interactions between wood and moisture. In this review, we describe current knowledge gaps in our understanding of moisture in wood and how modification has been and could be used to clarify some of these gaps. This review shows that introducing specific chemical changes, and even controlling the distribution of these, in combination with the variety of experimental methods available for characterization of moisture in wood, could give novel insights into the interaction between moisture and wood. Such insights could further contribute to applications in several related fields of research such as how to enhance the resistance to decomposition, how to improve the performance of moisture-induced wooden actuators, or how to improve the utilization of wood biomass with challenging swelling anisotropy.

Moisture influences most physical wood properties and plays an important role in degradation processes. Like most other porous materials, wood exhibits sorption hysteresis. That is, the moisture content is higher if equilibrium is reached by desorption than if it is reached by absorption under the same ambient climate conditions. The mechanism of moisture uptake by wood are different in the hygroscopic and over-hygroscopic moisture ranges and due to methodical issues, most studies of sorption hysteresis have been performed in the hygroscopic range. In the present study, total sorption hysteresis was separated into hysteresis in cell wall water and capillary water respectively in the whole moisture range by a novel combination of experimental techniques. Wood specimens were conditioned to several high moisture contents using a new system based on the pressure plate technique, and the distinction between cell wall water and capillary water was done with differential scanning calorimetry. The results showed that sorption hysteresis in wood cell walls exists in the whole moisture range. The cell walls were not saturated with water until the whole wood specimen was saturated which contradicts the long-held dogma that cell walls are saturated before significant amounts of capillary water are present in wood.

Wood is a porous, hygroscopic material with engineering properties that depend significantly on the amount of water (moisture) in the material. Water in wood can be present in both cell walls and the porous void-structure of the material, but it is only water in cell walls that affects the engineering properties. An important characteristic of wood is therefore the capacity for water of its solid cell walls, i.e. the maximum cell wall moisture content. However, this quantity is not straight-forward to determine experimentally, and the measured value may depend on the experimental technique used. In this study, we used a triangulation approach to determine the maximum cell wall moisture content by using three experimental techniques based on different measurement principles: low-field nuclear magnetic resonance (LFNMR) relaxometry, differential scanning calorimetry (DSC), and the solute exclusion technique (SET). The LFNMR data were furthermore analysed by two varieties of exponential decay analysis. These techniques were used to determine the maximum cell wall moisture contents of nine different wood species, covering a wide range of densities. The results from statistical analysis showed that LFNMR yielded lower cell wall moisture contents than DSC and SET, which were fairly similar. Both of the latter methods include factors that could either under-estimate or over-estimate the measured cell wall moisture content. Because of this and the fact that the DSC and SET methods are based on different measurement principles, it is likely that they provide realistic values of the cell wall moisture content in the water-saturated state.

Water is a key element for wood performance, as water molecules interact with the wood structure and affect important material characteristics such as mechanical properties and durability. Understanding wood-water interactions is consequently essential for all applications of wood, including the design of wood materials with improved durability by chemical modification. In this work, we used Raman micro-spectroscopy in combination with a specially designed moisture chamber to map molecular groups in wood cell walls under controlled moisture conditions in the hygroscopic range. We analyzed both untreated and chemically modified (acetylated to achieve two different spatial distributions of acetyl groups within the cell wall) Norway spruce wood. By moisture conditioning the specimens successively to 5, 50, and 95% relative humidity using deuterium oxide (D2O), we localized the moisture in the cell walls as well as distinguished between hydroxyl groups accessible and inaccessible to water. The combination of Raman micro-spectroscopy with a moisturizing system with deuterium oxide allowed unprecedented mapping of wood-water interactions. The results confirm lower moisture uptake in acetylated samples, and furthermore showed that the location of moisture within the cell wall of acetylated wood is linked to the regions where acetylation is less pronounced. The study demonstrates the local effect that targeted acetylation has on moisture uptake in wood cell walls, and introduces a novel experimental set-up for simultaneously exploring sub-micron level wood chemistry and moisture in wood under hygroscopic conditions.

Extractives found in the heartwood of a moderately durable conifer ( ) were compared with those found in a non-durable one ( ). We identified and quantified heartwood extractives by extraction with solvents of different polarities and gas chromatography with mass spectral detection (GC-MS). Among the extracted compounds, there was a much higher amount of hydrophilic phenolics in larch (flavonoids) than in spruce (lignans). Both species had similar resin acid and fatty acid contents. The hydrophobic resin components are considered fungitoxic and the more hydrophilic components are known for their antioxidant activity. To ascertain the importance of the different classes of extractives, samples were partially extracted prior to subjection to the brown-rot fungus for 2-8 weeks. Results indicated that the most important (but rather inefficient) defense in spruce came from the fungitoxic resin, while large amounts of flavonoids played a key role in larch defense. Possible moisture exclusion effects of larch extractives were quantified via the equilibrium moisture content of partially extracted samples, but were found to be too small to play any significant role in the defense against incipient brow-rot attack.

MEAT INSPECTION AND CONTROL IN THE SLAUGHTER HOUSE Meat inspection, meat hygiene and official control tasks in the slaughterhouse have always been of major importance in the meat industry and are intimately related to animal diseases and animal welfare. Huge steps have been taken over more than a century to prevent the transmission of pathogenic organisms and contagious diseases from animals to humans. Various factors influence the quality and safety of meat, including public health hazards (zoonotic pathogens, chemical substances and veterinary drugs) and animal health and welfare issues during transport and slaughter. Meat inspection is one of the most important programmes in improving food safety and its scope has enlarged considerably in recent decades. Globalization has affected the complexity of the modern meat chain and has provided possibilities for food frauds and unfair competition. During the last two decades many food fraud cases have been reported that have caused concern among consumers and the industry. Subsequently, meat inspection has been faced with new challenges. Meat Inspection and Control in the Slaughterhouse is an up-to-date reference book that responds to these changes and reflects the continued importance of meat inspection for the food industry. The contributors to this book are all international experts in the areas of meat inspection and the official controls limited to slaughterhouses, providing a rare insight into the international meat trade.This book will be of importance to students, professionals and members of the research community worldwide who aim to improve standards of meat inspection procedures and food safety.

Campylobacter spp., especially C. jejuni , is the most common zoonotic pathogen in humans worldwide. In Nordic countries, the prevalence of C. jejuni in broilers, which is an important reservoir of human infections, is generally low. Thus, other sources of domestically acquired infections besides chicken meat need to be considered. Game birds are known to carry a variety of zoonotic agents, including Campylobacter . The aim of this study was to investigate Campylobacter spp. carriage in a flock of reared pheasants at hunting in two successive samplings to better understand the dynamics of Campylobacter infections in pheasants. Overall, 72% of the intestinal samples were positive for Campylobacter spp. by direct culture on mCCDA. C. jejuni was the only species identified. The isolates were genotyped using whole genome sequencing (WGS), multilocus sequence typing (MLST), and ad hoc whole genome MLST (wgMLST). Two distinct C. jejuni clones were identified among the 18 isolates studied, representing MLST sequence types (STs) ST-45 and ST-699. The ST-45 isolates were closely related to previous human clinical isolates using core genome MLST (cgMLST). In contrast, the ST-699 isolates forming the dominant clone in the latter sampling were quite distinct from previously described cgMLST profiles from different hosts and sources worldwide. In conclusion, the intestine of reared pheasants is commonly colonized by C. jejuni and may carry genotypes relevant to infections in livestock and humans. Hygienic measures are needed to limit the spread of infection in reared flocks. Especially farmers and hunters having direct contact with pheasant offal need to be aware of the associated zoonosis risk to protect themselves and their working dogs alike. Biosecurity measures to improve the safety and reduce the zoonosis risk associated with pheasant farming should be further investigated.

Background European hedgehogs ( Erinaceus europaeus) are widely distributed across Europe. They may play an important role by spreading zoonotic bacteria in the environment and to humans and animals. The aim of our work was to study the prevalence and characteristics of the most important foodborne bacterial pathogens in wild hedgehogs. Results Faecal samples from 148 hospitalised wild hedgehogs originating from the Helsinki region in southern Finland were studied. Foodborne pathogens were detected in 60% of the hedgehogs by PCR. Listeria (26%) and STEC (26%) were the most common foodborne pathogens. Salmonella, Yersinia , and Campylobacter were detected in 18%, 16%, and 7% of hedgehogs, respectively. Salmonella and Yersinia were highly susceptible to the tested antimicrobials. Salmonella Enteritidis and Listeria monocytogenes 2a were the most common types found in hedgehogs. All S. Enteritidis belonged to one sequence type (ST11), forming four clusters of closely related isolates. L. monocytogenes was genetically more diverse than Salmonella , belonging to 11 STs. C. jejuni ST45 and ST677, Y. pseudotuberculosis O:1 of ST9 and ST42, and Y. enterocolitica O:9 of ST139 were also found. Conclusions Our study shows that wild European hedgehogs should be considered an important source of foodborne pathogens, and appropriate hygiene measures after any contact with hedgehogs and strict biosecurity around farms are therefore important.