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The historical archive of the Greek Communist Party (paper, photographs etc) was badly affected in 1994 from a destructive flood. The aim of the paper is to report on the application of physicochemical methods to evaluate the damage and apply restoration techniques. The steps followed were: placing the ‘muddy’ material into fridges with low temperature to stop the development of the mould which was increasingly quick; cleansing and drying it, decontamination and sterilization in proper closets of 25 m3; adapt the space within the proper conditions and to insert the dried material, perform specific chemical treatment (De-acidification– Neutraliza-tion), solidify and restore by using Japanese preservation papers, place the material into folders and boxes with antacid – antifungal protection, computerize and store it electronically (digitalization). The purpose is to slow-down its chemical downgrade. The primary action that is taken for the future physicochemical course of the material is to secure stable humidity and temperature conditions as defined by scientific literature. All the above, at different levels, have contributed to the non-decomposition of cellulose.

Significance: Gas in scattering media absorption spectroscopy (GASMAS) enables noninvasive gas sensing in the body. It is developing as a tool for diagnosis and monitoring of respiratory conditions in neonates. Phantom models with relevant features to the clinical translation of GASMAS technology are necessary to understand technical challenges and potential applications of this technique. State-of-the-art phantoms designed for this purpose have focused on the optical properties and anthropomorphic geometry of the thorax, contributing to the source–detector placement, design, and optimization. Lung phantom mimicking the alveolar anatomy has not been included in the existent models due to the inherent complexity of the tissue. We present a simplified model that recreates inflated alveoli embedded in lung phantom. Aim: The goal of this study was to build a lung model with air-filled structures mimicking inflated alveoli surrounded by optical phantom with accurate optical properties (μa = 0.50 cm − 1 and μs′=5.4 cm−1) and physiological parameters [37°C and 100% relative humidity (RH)], and to control the air volume within the phantom to demonstrate the feasibility of GASMAS in sensing changes in pulmonary air volume. Approach: The lung model was built using a capillary structure with analogous size to alveolar units. Part of the capillaries were filled with liquid lung optical phantom to recreate scattering and absorption, whereas empty capillaries mimicked air filled alveoli. The capillary array was placed inside a custom-made chamber that maintained pulmonary temperature and RH. The geometry of the chamber permitted the placement of the laser head and detector of a GASMAS bench top system (MicroLab Dual O2 / H2O), to test the changes in volume of the lung model in transmittance geometry. Results: The lung tissue model with air volume range from 6.89 × 10 − 7 m3 to 1.80 × 10 − 3 m3 was built. Two measurement sets, with 10 different capillary configurations each, were arranged to increase or decrease progressively (in steps of 3.93 × 10 − 8 m3) the air volume in the lung model. The respective GASMAS data acquisition was performed for both data sets. The maximum absorption signal was obtained for configurations with the highest number of air-filled capillaries and decreased progressively when the air spaces were replaced by capillaries filled with liquid optical phantom. Further studies are necessary to define the minimum and maximum volume of air that can be measured with GASMAS-based devices for different source–detector geometries. Conclusions: The optical properties and the structure of tissue from the respiratory zone have been modeled using a simplified capillary array immersed in a controlled environment chamber at pulmonary temperature and RH. The feasibility of measuring volume changes with GASMAS technique has been proven, stating a new possible application of GASMAS technology in respiratory treatment and diagnostics.

This research aims to develop white bread shelf-life extension sachet with controlled release of antimicrobial agent prepared from multicomponent bio-based materials. The structure of antimicrobial sachet consists of two major parts i.e., controlled release part and active part. The first part produced from paper coated with ethylene vinyl alcohol (EVOH). The second one was an active part which produced from biodegradable poly(butylene succinate) (PBS) and geraniol essential oil blend. Inhibition clear zone test results showed that a suitable geraniol concentration, encapsulated in PBS, was 10 wt%. Based on the water vapor transmission test, coating paper with EVOH for three times (around 450 μm) was an optimal condition for the use as a controlled release part. Release test indicated that geraniol migration concentration increased with increasing the relative humidity (RH) in the package which correlated to the moisture liberated from bread slice. Shelf-life extension study informed that the spoilage of bread stored with antimicrobial sachet was delayed by more than three weeks. In summary, this antimicrobial sachet could be used in food shelf-life extension purpose which easily placed in any food container. This is an alternative way of food waste minimization.

The study was performed at Billerudkorsnäs at the section Box Lab which offers knowledge and solutions for packaging. Paper that can be used to create packaging interacts with the surrounding environment, but has only been tested for a few climates. This thesis aims to investigate more climates and see how paper is affected by humidity and temperature and try to determine the cause of the results. The methods used to measure this was primary tensile test and moisture content analysis but also a test to evaluate creep was performed in climates with high humidity. From this, the mechanical properties of the paper were calculated. The test was performed in a climate chamber and the choice of methods was limited by what could be performed in the climate chamber. The materials tested were chosen to give a good representation of what is commonly used in the containerboard business. The climates for testing were selected from the ability of the climate chamber as well as interesting climates for the company. The results show that the papers are weakest at high RH, but the results indicate that the temperature solely impacts the properties of the paper. The highest moisture content does not necessarily mean the lowest value for a chosen property. The causes for the results are not clear since the patterns found are not bound to a certain quality but rather to paper in general. Therefore, more research on the area is suggested to try to determine what causes the material to react to temperature.

Aims The purpose of this study was to evaluate the effects of altered environmental conditions on the persistence of Francisella tularensis bacteria and Venezuelan equine encephalitis virus (VEEV), on two material types. Methods and results Francisella tularensis (F.t.) and VEEV were inoculated (c. 1 × 108 colony-forming units or PFU), dried onto porous and nonporous fomites (glass and paper), and exposed to combinations of altered environmental conditions ranging from 22 to 60°C and 30 to 75% relative humidity (RH). Viability of test organism was assessed after contact times ranging from 30 min to 10 days. Inactivation rates of F.t. and VEEV increased as both temperature and/or RH were increased. Greater efficacy was observed for paper as compared to glass for both test organisms. Conclusions The use of elevated temperature and RH increased rate of inactivation for both organisms and greater than six log reduction was accomplished in as little as 6 h by elevating temperature to approximately 60°C. Significance and impact of the study These results provide information for inactivation of nonspore-forming select agents using elevated temperature and humidity which may aid incident commanders following a biological contamination incident by providing alternative methods for remediation.

Gold nanoparticles (AuNPs) were directly synthesized and anchored on lignocellulose fiber without an external immobilizing agent via a facile green approach using unbleached kraft (UBK) softwood pulp. The obtained AuNPs were confirmed by UV–vis diffuse reflectance spectroscopy, field-emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The antioxidant behavior of the as-prepared AuNP-UBK fiber nanocomposite was evaluated by free radical scavenging of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH). The nanocomposite fiber exhibited greatly enhanced radical scavenging activity compared to that of the pure fiber. As a consequence, AuNP-UBK nanocomposite paper showed exceptional antioxidant performance with a radical scavenging rate of over 98%, which is attributed to the synergistic effects of adsorption by the fiber–fiber network and subsequent catalytic activity of the AuNPs. This research indicated that AuNP-UBK fiber nanocomposites could be a new candidate for antioxidant active packaging for use in food preservation.

Given the increasing number of connected devices as a consequence of the Internet of Things (IoT) revolution, the issue of the removal and recycling of electronics is becoming more and more urgent. In this context, biodegradable electronics is expected to be one of the biggest technological revolutions to tackle this problem. Following this direction, in this work we present the fabrication and characterization of temperature and humidity sensors based on biodegradable materials with the goal of making their removal easier as well as reducing their environmental impact. In particular, these multi-sensing devices were fabricated following a screen-printing process using a carbon-based paste and a conjugated polymer, both on paper and on a water soluble substrate. The results are more than promising and show how with our biodegradable sensors it is possible to obtain a sensitivity of 1 dec/20%RH to moisture content and around 0.04%/°C sensitivity to temperature. It is demonstrated that the simplicity and flexibility of the fabrication approach followed in this work paves the way to a set of new “green” IoT nodes that could be extended to wide range of sensing applications.

Critical bleeding causes over 2 million deaths a year. Early hypofibrinogenemia is a strong predictor of mortality in critically bleeding patients. The early replenishment of fibrinogen can significantly improve outcomes. However, over replenishment can also be dangerous. Furthermore, there is no rapid, cheap, hand-held diagnostic that can aid critically bleeding patients in fibrinogen replacement therapy. In this study, we have developed a hand-held paper diagnostic that measures plasma fibrinogen concentrations. The diagnostic has the potential to be used as a point of care device both inside and outside of hospital settings. It can vastly reduce the time to treatment for fibrinogen replacement therapy. The diagnostic is a two-step process. First, thrombin and plasma are added onto horizontially-orientated paper strips where the fibrinogen is converted into fibrin, drastically increasing the plasma's hydrophobicity. Second, an aqueous blue dye is pipetted onto the strips and allowed to wick through the fibrin. The distance the blue dye wicks through the strip correlates precisely to the fibrinogen concentration. The diagnostic can provide results within a minute. It can distinguish low fibrinogen concentrations (ie.2 g/L) from normal fibrinogen concentrations. It shows remarkable reproducibility between healthy individuals. It is unaffected by common blood conditions such as acidosis, blood alcohol, severe hypertriglyceridemia, severe haemolysis and warfarin administration. Finally, it is unaffected by humidity and can withstand cold temperatures.

Ninhydrin was implemented as the primary police method of developing latent fingermarks on paper, cardboard and some other porous surfaces from the late 1960s. Some researchers have used individual amino acids, or mixtures of amino acids, as a method of testing the effectiveness of reagent formulations. It was not however known whether simple mixtures of amino acids could effectively emulate latent fingermarks in reactions with reagents such as ninhydrin. The first part of this study compared the effects of ninhydrin fingermark treatments used internationally in various police laboratories on test targets created by inkjet printing graduated concentrations of a representative mixture of amino acids in a series of blocks on paper. Variations in intensity of development were observed between laboratories which used various formulations and heat and humidity post treatment protocols. In a further trial in 2015 several participants in the International Fingerprint Research Group (IFRG) meeting processed test targets in their own laboratories and submitted them for measurement. Again, variation in developed intensity was observed. The depletion of the activity of ninhydrin solutions during use was also investigated in early evaluations of the test targets. An established fingerprint laboratory then processed a number of samples from a batch of targets to examine batch consistency. This was followed by designing a new test target which enabled comparisons between the developed intensity of printed test target blocks alongside depletion series of split, natural donor fingermarks. A panel of 20 donors provided depletion fingermarks and four ninhydrin formulations and treatment protocols were used. The developed test target blocks were scanned, intensity of development measured, and the results compared with the fingermark development which was evaluated by three assessors using two types of scale. Good correlation between the intensity of the developed test targets and latent fingermark quality and intensity scores was observed with the four ninhydrin treatment protocols, including some which used deliberately downgraded ninhydrin concentrations. This type of evaluation was carried out a second time to investigate modified heat and humidity protocols. The use of such test targets for routine reagent quality control and process verification would appear to be far more accurate and reliable than the use of small numbers of donor fingermarks. It is not clear why the different ninhydrin formulations investigated in the latter part of the work have very different optimum post treatment heating regimes.

International audience; The Covid-19 coronavirus, SARS-CoV-2, is inactivated much faster on paper (3 h) than on plastic (7 d). By classifying materials according to virus stability on their surface, the following list is obtained (from long to short stability): polypropylene (mask), plastic, glass, stainless steel, pig skin, cardboard, banknote, cotton, wood, paper, tissue, copper. These observations and other studies suggest that SARS-CoV-2 may be inactivated by dryness on water absorbent porous materials but sheltered by long-persisting micro-droplets of water on waterproof surfaces. If such physical phenomenons were confirmed by direct evidence, the persistence of the virus on any surface could be predicted, and new porous objects could be designed to eliminate the virus faster.

Environmental and health concerns are driving the need for new materials in food packaging to replace poly- or perfluorinated compounds, aluminum layers, and petroleum-based polymers. Cellulose nanofibrils (CNF) have been shown by a number of groups to form excellent barrier layers to oxygen and grease. However, the influence of lignin-containing cellulose nanofibrils (LCNF) on film barrier properties has not been well reported. Herein, thin films (16 g/m2) from LCNF and CNF were formed on paper substrates through a filtration technique that should mimic the addition of material at the wet end of a paper machine. Surface, barrier and mechanical attributes of these samples were characterized. The analysis on the surface free energy and water contact angle pointed to the positive role of lignin distribution in inducing a certain degree of water repellency. The observed oxygen transmission rate (OTR) and water vapor permeability (WVP) values of LCNF-coated samples were nearly similar to those with CNF. However, the presence of lignin improved the oil proof performance, these layered designs exhibited an excellent resistance to grease (kit No. 12). The attained papers with LCNF coat were formed into bowl-like containers using metal molds and a facile oven drying protocol to evaluate their resistance to oil penetration over a longer period. The results confirmed the capability of LCNF layer in holding commercially available cooking oils with no evidence of leakage for over five months. Also, an improvement in the tensile strength and elongation at break was observed in the studied papers. Overall, the proposed packaging material possesses viable architecture and can be considered as a fully wood-based alternative for the current fluorocarbon systems.

The rapid development of wearable sensing technology exhibits unprecedented opportunities for artificial intelligence by establishing an interactive interface between the physical and the virtual worlds. Energy preservation and multi-functional integration are central for the enhancement of perception and sustainability of wearable electronics. Herein, to address the above two critical challenges, we presented a printed silk-fibroin-based triboelectric nanogenerator (PS-TENG), which can efficiently scavenge the bio-mechanical energy and precisely detect components of environmental humidity and human body motions simultaneously. An industrial mass-fabrication technology, i.e. screen-printing process, was successfully optimized to manufacture graphite-based microscale surface patterns atop polymeric soft substrate to form interdigital electrodes, which was covered by a thin layer of silk fibroin to realize the PS-TENG. The proposed wearable PS-TENG exhibited a remarkable output performance, and the voltage, the current and the power density achieved up to 666 V, 174.6 μA, 412 μW/cm2, respectively. Furthermore, this ultra-thin foldable PS-TENG possesses incredible features for multi-functional wearable sensing. With the help of the unique selective absorption property of silk fibroin, it was firstly reported that the existing states of water molecules (i.e., liquid and gaseous) in the air were successfully distinguished. Moreover, as attractive potential applications, it was demonstrated to accurately discriminate the health situation of human body (i.e., respiratory monitoring and joints motion recognizing) based on the capacitive and the triboelectric principles respectively, which is a novel combination of passive sensing and active sensing mechanisms within a single wearable device.

Ricin is a highly-toxic compound derived from castor plant beans. Several incidents involving contamination of residences and buildings due to ricin production or dissemination have occurred in recent years. The goal of this study was to determine whether ricin bioactivity could be attenuated in reasonable time via simple modifications of the indoor environment. Attenuation was assessed on six different materials as a function of temperature, relative humidity (RH), and contact time, using both a pure and crude preparation of the toxin. Ricin bioactivity was quantified via a cytotoxicity assay, and attenuation determined as the difference in ricin recovered from test and positive controls. The results showed that pure ricin could be attenuated successfully, while the crude ricin was generally more persistent and results more variable. We found no significant attenuation in crude ricin after two weeks at typical indoor environmental conditions, except on steel. Attenuation mostly improved with increasing temperature, but the effect of RH varied. For pure ricin, heat treatments at 40°C for 5 days or 50°C for 2–3 days achieved greater than 96% attenuation on steel. In contrast, appreciable recovery of the crude ricin preparation still occurred at 40°C after two weeks.

International audience; The fracture process in two fiber network materials, a low- and a high-density paper, is analyzed experimentally and numerically. The high-density paper is able to localize continued fracture to very small defects while a rather large defect is required in the low-density paper. Whereas the high-density paper has a homogeneous and limited variation in local mass density, the low-density paper is substantially more heterogeneous and has a higher local mass density variation. It is hypothesized that these fairly large regions of lower mass density govern the fracture process in paper and similar fiber network materials. A nonlocal fracture model is applied to describe and capture this length scale phenomenon and intents to simulate forces bridged over distant regions in the material via connected fibers. The suggested fracture hypothesis is consistent with experiments and hence offers an explanation to why network materials with different mass density variation may fracture differently.

Newspaper is known to turn yellow over time. We show here that this yellowing process is sensitive to oxygen when exposed to UV light, leading to oxygen sensing. Oxygen sensing is critical to many applications, including industrial process control and breath analysis, but the existing oxygen sensors have limitations, especially for breath analysis that operates at 100% humidity. The UV irradiation also triggers fluorescence emission from newspaper, and the fluorescence intensity depends on oxygen concentration, providing an additional oxygen sensing method. Newspaper is stable in ambient air, and reactive to oxygen only with UV activation, which overcomes the instability issue of a typical colorimetric sensor in ambient air. The newspaper oxygen sensor works in 100% relative humidity air, containing various interferents. These unique properties of newspaper promise low cost and reliable oxygen sensing applications.

An inexpensive red, green, blue (RGB) color sensor was developed for detecting low ppm concentrations of hydrogen cyanide gas. A piece of glass fiber filter paper containing monocyanocobinamide [CN(H(2)O)Cbi] was placed directly above the RGB color sensor and an on chip LED. Light reflected from the paper was monitored for RGB color change upon exposure to hydrogen cyanide at concentrations of 1.0–10.0 ppm as a function of 25%, 50%, and 85% relative humidity. A rapid color change occurred within 10 s of exposure to 5.0 ppm hydrogen cyanide gas (near the NIOSH recommended exposure limit). A more rapid color change occurred at higher humidity, suggesting a more effective reaction between hydrogen cyanide and CN(H(2)O)Cbi. The sensor could provide the first real time respirator end-of-service-life alert for hydrogen cyanide gas.

Intense and persistent exposure to indoor-air biological agents has been associated with the appearance of allergic diseases. Archives and libraries Indoor environments in tropical countries are an important reservoir of fungal propagules.To evaluate the degree of air pollution with allergenic fungi in a repository of frequently-manipulated documents.Air sampling was performed by two methods: active (biocollector) and passive (sedimentation plate). Fungi were taxonomically identified, and spores were measured to determine their penetrability in the human respiratory tract, and its impact on episodes of allergy.In terms of concentration and diversity, the local environment behaved as a fungal propagule reservoir, which showed that there is significant health risk for the staff that manipulates the documents. Some spores were shown to be able to reach the lower respiratory tract when inhaled, which increases their allergenic and pathogenic potential. Aspergillus, Cladosporium, Penicillium and Alternaria, which are referred to as highly allergenic fungi, were prevalent.Aerobiological studies are a valuable tool for the treatment of patients with allergy to fungi and other disorders they produce.Antecedentes: La exposición intensa y persistente a agentes biológicos del aire interior se ha relacionado con la aparición de trastornos a la salud. Se ha establecido asociación entre las condiciones ambientales, los hongos anemófilos y los estados alérgicos. Los ambientes interiores de archivos y bibliotecas en países tropicales son un reservorio importante de propágulos fúngicos, cuyo seguimiento y control son primordiales en la prevención de enfermedades ocupacionales. Objetivo: Evaluar el grado de contaminación del aire con hongos alergénicos viables en un depósito de documen-tos que se manipulan con alta frecuencia (ambiente laboral). Métodos: El muestreo aéreo se realizó por métodos activo (biocolector) y pasivo (sedimentación en placa). Los aislados se identificaron taxonómicamente, se medieron las esporas para determinar su penetrabilidad en el tracto respiratorio humano y se evaluó su impacto en los episodios de alergia. Resultados: En concentración y diversidad, el ambiente local se comportó como un reservorio de propágulos fúngicos, lo cual evidenció riesgo para la salud del personal. Se determinó que algunas esporas pueden alcanzar el tracto respiratorio inferior, con lo que se acentúa su potencial alergénico y patogénico. Prevalecieron Aspergi-llus, Cladosporium, Penicillium y Alternaria, referidos como hongos altamente alergénicos. Conclusión: Los estudios aerobiológicos constituyen una herramienta de gran valor para el tratamiento de los pacientes con alergia a los hongos y otros trastornos que estos producen.

New biodegradable nanocomposites have been successfully prepared by incorporating modified nano-cellulose fibers (NCF) in a biodegradable polylactic acid (PLA) matrix in this work. The hydrophobic-modified NCF was obtained by grafting hydrophobic monomers on NCF to improve the compatibility between NCF and PLA during blending. The resulting NCF/PLA composites were then applied on paper surface via a cast-coating process in an attempt to reduce the water vapor transmission rate (WVTR) of paper. The WVTR tests, conducted under various testing conditions and with different coating weights, demonstrated that the modified NCF/PLA composites coating played a critical role in lowering WVTR of paper. The lowest WVTR value was 34 g/m(2)/d, which was obtained with an addition of 1% of modified NCF to PLA and the composites coating weight at 40 g/m(2) and substantially lower than the control value at 1315 g/m(2)/d. The paper coated with the modified biodegradable composite is promising as green-based packaging materials.

Current methods of monitoring breathing require cumbersome, inconvenient, and often expensive devices; this requirement sets practical limitations on the frequency and duration of measurements. This article describes a paper-based moisture sensor that uses the hygroscopic character of paper (i.e. the ability of paper to adsorb water reversibly from the surrounding environment) to measure patterns and rate of respiration by converting the changes in humidity caused by cycles of inhalation and exhalation to electrical signals. The changing level of humidity that occurs in a cycle causes a corresponding change in the ionic conductivity of the sensor, which can be measured electrically. By combining the paper sensor with conventional electronics, data concerning respiration can be transmitted to a nearby smartphone or tablet computer for post-processing, and subsequently to a cloud server. This means of sensing provides a new, practical method of recording and analyzing patterns of breathing.

BACKGROUND The effect of innovative multilayer packaging materials versus a standard one on biscuit quality was studied during accelerated storage at 25, 35, 45 °C and 50% relative humidity for 92 days. Three different packaging materials were used: metalized orientated polypropylene (OPP)/paper (control); metalized poly-lactic acid (PLA)/paper; metalized OPP with ethylene vinyl acetate pro-oxidant additive (EVA-POA)/paper. EVA-POA additive is used to make the plastic layer biodegradable. Various quality sample parameters (moisture, water activity (aw), texture, peroxide value (PV), hexanal) were analysed during storage. Rate constants (k) and activation energies (Ea) of hydration reactions and hexanal formation were calculated. RESULTS No remarkable differences in the evolution of primary and secondary lipid oxidation were observed among differently packed biscuits during storage. All samples maintained PV levels between 4 and 14 meq O2 kg−1 oil. The product in flexible packaging with PLA reached the highest moisture and aw levels, but they did not significantly and adversely affect the other quality characteristics. CONCLUSION The obtained results demonstrate that the new tested packaging materials were suitable for commercial biscuit storage, having similar performance and preservation effects on the overall product quality to those of the standard one. Furthermore, these results could make a contribution to the food industry, encouraging the use of packaging materials with a negligible environmental impact as an alternative to petroleum-based ones. © 2014 Society of Chemical Industry

The influence of packaging materials (plastic bucket, low density polyethylene [LDPE] bags and paper bags) on quality attributes of the flour of 2 cassava cultivars (TME 419 and UMUCASS 36) stored at 23 ± 2 °C and 60% relative humidity (RH) were investigated for 12 wk. Cassava flour from each package type was evaluated for proximate composition, physicochemical properties and microbial growth at 4-wk intervals. Total color difference (∆E) of both cassava flour cultivars increased with storage duration. Flour packed in plastic bucket had the lowest change in color (3.2 ± 0.42) for cv. "TME 419ˮ and (4.1 ± 0.87) for cv. "UMUCASS 36ˮ at the end of week 12. Total carotenoid decreased across all treatment, and after the 12 wk storage, the highest total carotenoid retention (1.7 ± 0.02 and 2.0 ± 0.05 μg/mL) was observed in flour packed in plastic bucket. However, cassava flour in paper bag had the lowest microbial count of 3.4 ± 0.03 and 3.4 ± 0.08 log cfu/g for total aerobic mesophilic bacteria and fungi, respectively.

Food contact is characterised in various terms, all of which are somewhat ill-defined. This work investigated the simplification that migration from food contact materials into dry food virtually exclusively proceeds through the gas phase, which would imply that the migration of essentially non-volatile components is negligible. It is shown here that this is not necessarily appropriate: for newspaper printed with an ink based on essentially non-volatile polyalphaolefins (PAO) as the main solvent, the migration into polenta and a baking mix reached 64% and 66% respectively of the content in the paper in merely 20 days at ambient temperature. Migration of involatile substances into dry foods implies diffusion through the paper to the small contact points. It depended on particle size, as this determines the density of the contacts. The diffusion rates within the food contact material and the food, including the transfer from one particle to the next, are other determining factors. This leaves the question whether such migration can be modelled or tested in a systematic manner (simulation), or whether it needs to be determined on a case-by-case basis.