<div>Fresh produce has been the leading source of foodborne illness outbreaks in the US, surpassing typical pathogen carriers such as meat, dairy, and seafood. Among the fresh produce popular to the consumers, cantaloupe and sprouts are mostly susceptible to pathogen contaminations and outbreaks. However, it has been a challenge to address the key factor in the contamination - the biofilms formed by pathogens are highly resistant to conventional washing and cleaning procedures. For cantaloupe, the net-like and porous surface forms a barrier for washing. For sprouts, the fragile texture of seedlings prevents aggressive cleaning operation and biofilm removal.</div><div><br></div><div>In this study, innovative interventions were developed to improve microbial safety of fresh produce, using cantaloupe and alfalfa sprouts as models. For cantaloupe, abrasive brushing was designed to remove pathogen biofilm from cantaloupe. Our research found pathogens could form biofilm at cantaloupe rind surface as the residence time of pathogens increased. Biofilm formed on cantaloupe rind was imaged by cryo-scanning electron microscopy (cryo-SEM), and its resistance to sodium hypochlorite and lauroyl arginate ethyl (LAE) was confirmed. Furthermore, abrasive brushing with peroxyacetic acid (PAA) could effectively remove biofilm formed at cantaloupe rind. The efficacy of this novel cleaning technique was highly desirable, which could achieve 3 log reduction in pathogen population. Mechanism of abrasive brushing to remove biofilm at cantaloupe rind surface was also proposed. Conceivably, brushing with diatomaceous earth (DE) and PAA could be an innovative and cost-effective method to remove pathogen biofilm from cantaloupe rind.</div><div><br></div><div>For alfalfa sprouts, since most of the outbreaks are linked to the sprouting seeds, seed disinfection treatments are considered to be the most effective method to improve microbial safety of sprouts. In this study, a newly developed alginate-based, antimicrobial seed coating treatment was evaluated for its efficacy to reduce foodborne pathogens from alfalfa seeds and sprouts. The calcium alginate coating in the presence of 2.5% lactic acid (CA-LA coating) reduced foodborne pathogens inoculated on alfalfa seeds to an undetectable level on day 1 during 28 day-seed storage, while chlorine (20,000 ppm) or lactic acid (2.5%) treatment took longer time to reach the same level. With sprouts, CA-LA coating resulted in > 2.5 log reduction for pathogen cells. In contrast, log reduction was < 0.6 for either chlorine (20,000 ppm) or lactic acid (2.5%) treatment. In general, this study indicated the effect of calcium alginate coating on reducing bacterial load of alfalfa seeds and sprouts, however, the germination rate of treated seeds was compromised due to the addition of lactic acid in the seed coating. Further study is needed to select antimicrobial compounds with minimum impact on germination rate of seeds.</div><div><br></div>

Les emballages plastique sont tristement connus pour la pollution accrue qu’ils entrainent. Les effets directs sur l’homme sont principalement dus à la migration de composés depuis le plastique vers les aliments qu’il contient. Ces composés ont des origines diverses : additifs, impuretés, produits de dégradations, réactions non contrôlées… A défaut de savoir arrêter cette migration, nous avons choisi d’en tirer profit grâce à de nouveaux matériaux, appelés matériaux actifs. Ces derniers ont pour objectifs de prolonger la durée de vie des aliments grâce à une migration dite « positive ». L’utilisation d’additifs naturels pose cependant un problème lié à leur résistance à la température. La problématique est donc de trouver des additifs naturels résistant à la température de mise en œuvre des polymères, tout en les stabilisant. C’est dans ce contexte que mon sujet de thèse a été mis en place, au sein du projet Foodyplast (POCTEFA). La thèse se découpe en quatre parties. Un état de l’art est tout d’abord présenté. Le chapitre suivant détaille les différentes techniques utilisées pour la réalisation et la caractérisation de nos matériaux ainsi que le développement d’une nouvelle méthode basée sur la spectrométrie de masse (LESA-MS). Le troisième chapitre aborde en détail la mise en œuvre de nouveaux matériaux stabilisés par des additifs naturels ainsi que leurs caractérisations physico-chimiques. Nous avons prouvé que l’utilisation conjointe de ces additifs (alpha-tocopherol/acide ascorbique et alpha-tocopherol/tannins) permet d’accroitre significativement l’effet de stabilisation sur la matrice polymère (innovation brevetée). Ces matériaux ont également montré être recyclable jusqu’à 9 fois sans dégradations. Enfin, le dernier chapitre reprend la nouvelle méthode du LESAMS, développée au chapitre 2, pour l’appliquer à la caractérisation de nos matériaux. Cette méthode est comparée à celle de la norme européenne en vigueur et ouvre de réelles perspectives d’analyses performantes dans les polymères pour différentes applications. / Plastic packagings are notorious for the increased pollution they cause. The direct effects on humans are mainly due to the migration of compounds from plastic to the foods it contains. These compounds have various origins: additives, impurities, degradation products, uncontrolled reactions… For lack of being able to stop this migration, we chose to take advantage of it with new materials, called active materials. The objectives of these materials are to extend the shelf life of foods through a so-called “positive” migration. However, the use of natural additives is complicated due to their poor resistance to temperature. The problem is therefore to find natural additives resistant to the polymers’ extrusion temperatures, while stabilizing them. It is in this context that my thesis topic was set up within the Foodyplast project (POCTEFA). The thesis is divided into four parts. A state of the art is first presented. The following chapter details the various techniques used to produce and characterize our materials and the development of a new method based on mass spectrometry (LESA-MS). The third chapter discusses in detail the implementation of new materials stabilized by natural additives and their physico-chemical characterization. We have shown that the joint use of these additives (alpha tocopherol/ascorbic acid and alpha-tocopherol/tannins) significantly increases the stabilization effect on the polymer matrix (patented innovation). These materials have also shown to be recyclable up to 9 times without degradation. Finally, the last chapter potential of the new LESA-MS method (developed in Chapter 2) for its efficient of our materials. This method is compared to that of the current European standard and opens up real prospects for performing analyses in polymers for different applications.

In this study we investigate the synergistic effect of low frequency ultrasonication (14, 22, and 47 kHz) on antimicrobial activity of Cecropin P1 against Escherichia coli. The hypothesis was tested by comparing three different treatments (1) ultrasonication only (2) Cecropin P1 only (3) combination of both. The results showed that the combined treatment deactivate E. coli more efficiently by six order of magnitude. The mechanism of membrane permeabilization due to Cecropin P1 is also investigated using dye leakage experiment. The result indicated pore formation and carpet mechanism. Finally, a mathematical modeling is proposed to explain the synergistic effect, allowing us to make better prediction for cell deactivation.

The demand for bio-plastics is constantly growing, due to the increasing use of synthetic plastic, their non environmentally friendly properties and long degradation time. This thesis explored the possibility to use starch-lignosulfonate mixtures for food packaging. Films are prepared from potato starch and two different types of lignosulfonates, calcium and sodium respectively using mold casting. The films are compared to pure potato starch films in respect to their mechanical properties and moisture absorption. Characterization of the films is also conducted using scanning electron microscopy, energy-dispersive X- ray spectroscopy and light microscopy to see the interaction between the potato starch and lignosulfonates. The tensile test reveals that neither of the lignosulfonates do have a plasticizing effect on the potato starch films. The energy-dispersive X-ray spectroscopy conceded that the lignosulfonates are homogeneously dispersed throughout the film both on the surface and cross section. The moisture absorption test showed that the uptake of water does not decrease by adding lignosulfonates to the potato starch film. From these results it can be concluded that it is possible to produce films from potato starch and lignosulfonates in various ratios. But the potato starch:lignosulfonate films are not a viable option for food packaging due to their brittleness and high moisture uptake. / Efterfrågan på bioplast växer ständigt på grund av den ökande användingen av syntetiska plaster, deras icke miljövänliga egenskaper och den långa nedbrytningstiden. Denna avhandling undersöker möjligheten att använda blandningar av stärkelse-lignosulfonat i livsmedelsförpackningar. Potatisstärkelse och två olika typer av lignosulfonater med kalcium och natrium användes för att tillverka filmer genom formgjutning. Filmerna jämförs med filmer med ren potatisstärkelse, med avseende på deras mekaniska egenskaper och fuktabsorption. Karakterisering av filmerna genomförs även med hjälp av svepelektronmikroskop, energiröntgenspektroskopi och ljusmikroskopi för att se interaktionen mellan potatisstärkelse och lignosulfonater. Dragproverna visar att ingen av lignosulfonaterna har mjukgörande effekt på potatisstärkelsefilmerna. Energiröntgenspektroskopin visade att lignosulfonaterna är homogent dispergerade i hela filmen både på ytan och i tvärsnittet. Fuktabsorptionstestet visade att upptaget av vatten inte minskar genom tillsats av lignosulfonater i potatisstärkelse-filmen. Från dessa resultat kan man dra slutsatsen att det är möjligt att framställa filmer från potatisstärkelse och lignosulfonater i olika förhållanden. Men potatisstärkelse: lignosulfonatfilmer är inte ett hållbart alternativ för livsmedelsförpackningar på grund av sin sprödhet och höga fuktupptagning.

This study aims to identify problems that food companies may encounter during the transition from un-recyclable plastic packaging, to recyclable plastic packaging. The study is based on a survey and a case study. The survey was answered by 16 food companies who, with their signature of the Plastinitiativet 2022, have taken responsibility for increasing the recyclability of their plastic packaging. The case study focuses on a food company that may want to sign Plastinitiativet 2022, but first need to know more about their current plastic usage and what possibilities they have to increase the recyclability of their plastic package. Both studies show that food companies may experience some problems in the transition to a more recyclable plastic usage. A change in the plastics material and color may result in unexpected problems. Multilaminates and barrier materials have special functions but lower the recyclability. Laser marking and/or minimal printing, labels, shrink labels and adhesives on the packaging do not appear to be problematic for most of the companies. Signing Plastinitiativet 2022 seems to motivate the food companies to take measures, to increase the recyclability of their plastic packaging. All food companies will probably encounter problems of varying severity. The severity varies depending on the type of plastic used at present and the type of food that is packaged. The transition is also likely to contribute to higher materials- and staff costs for food companies.

No description available.

No description available.

Studies have shown that traditional food packaging for the fast food industry leach toxic chemicals into the food products. Some of these toxins are known endocrine disruptors, which results in reproductive issues as well as hormone imbalances. Alternatives to traditional food packaging have been addressed with special attention to bioactive, biopolymers, and biodegradable packaging in addition to active and intelligent packaging. The hypothesis states that customers will have high demand for more environmentally sustainable fast food packaging, while the alternative hypothesis states that demand will not be high enough to financially support the costly introduction of more environmental packaging products. The data attained suggest that the hypothesis will not be rejected. However, there are not conclusive results in terms of the alternative hypothesis, as further studies that address economical concerns must be completed. In terms of consumer demand, 94.92% preferred environmentally sustainable packaging over traditional packaging materials.

In this paper the parametric design and functional optimisation of thin-walled structures made from plastics for food packaging is considered. These objects are produced in such vast numbers each year that one important task in the design of these objects is to minimise the amount of plastic used, subject to functional constraints, to reduce the costs of production and to conserve raw materials. By means of performing an automated optimisation on the possible shapes of the food containers, where the geometry is parametrised succinctly, a strategy to create the optimal design of the containers subject to a given set of functional constraints is demonstrated.

Det talas allt oftare om de problem som världens plastanvändning åsamkar miljön genom exempelvis nedskräpning och mikroplaster. Det finns många olika typer och användningsområden för plast. Den typ som anses värst i avseende till miljöpåverkan är plasten som används en gång och sedan förlorar sin funktion, det som idag kallas engångsplast. Ett av de vanligaste områdena där engångsplast används är inom förpackningsindustrin för livsmedel. År 2019/2020 växte en projektidé bland en grupp elever om att se över alternativa förpackningsmaterial till främst frukt och grönt i matvaruhandeln. Idéen utvecklades och vid en expo på Textilhögskolan år 2020 presenterades ett citrusnät för ekologiska citroner stickat på en manuell stickmaskin i pappersgarn. Som fortsättning på arbetet är nu nästa steg att undersöka möjligheterna att sticka en motsvarande prototyp på en industriell maskin och vilka utmaningar som följer. Stickningen genomfördes i Borås på Textilhögskolans trikålabb. Maskinen som användes är en flatsticksmaskin av typen STOLL CMS822 HP knit and wear. Pappersgarn av olika garnnummer kom uteslutande från företaget OJO+ Fibers och baseras på pappersmassa från manillaplantan. Två bindningar stickades, en mesh-bindning och en stickning med flotteringar. Mesh-bindningen testades även med garn av olika garnnummer och olika antal ingående garn. De viktigaste parametrarna för möjligheten att sticka på industriell flatsticksmaskin visade sig vara garnets styrka, styvhet samt maskinens delning. Efter två separata produktionsgenomgångar genomfördes en visuell bedömning som avgjorde vilka stickningar som lämpade sig att gå vidare till ett dragprovstest. Standarden som användes för dragprovstest var (SS-EN ISO 13934–1:2013) och genomfördes på en Tinius Olsen H10KT (Elastocon). Fem provkroppar av varje stickning testades först i torrt- och sedan vått tillstånd genom blötläggning enligt standard. För att jämföra data från dragprovstestningen genomfördes en variansanalys för att upptäcka eventuella skillnader mellan de olika konstruktionerna. Variansanalys genomfördes även inom varje grupp för att undersöka skillnader mellan torra och våta prover av samma konstruktion. Resultatet från dragprovet visar en stor spridning i datamaterialet. På grund av spridningen går det inte att statistiskt säkerställa några slutsatser kring vilken konstruktion som är starkast. Främsta anledningen till spridningen är avvikelser från standarden som var nödvändiga för att genomföra testingen samt faktumet att (SS-EN ISO 13934–1:2013) huvudsakligen är till för vävda varor, ej stickade. Två av mesh-konstruktionerna kunde påvisa signifikant skillnad i mätresultatet mellan de våta respektive torra proverna, som då visade en svag tendens till att de våta proverna klarade högre spänning. Detta kan komma till användning för att enkelt öka garnets styrka vid stickning. / There’s an ongoing worldwide discussion regarding the environmental impact of plastic use. Single- use plastic is considered one of the most problematic due to the loss of functionality after one use. A common industry using single-use plastic is the food packaging industry. In 2019/2020, a project idea grew to review alternative packaging materials for fruits and vegetables. A prototype was presented at the Swedish School av Textile’s expo in 2020, a citrus net hand-knitted in paper yarn for organic lemons. The next step was to investigate the possibility of knitting paper nets on industrial machines and what difficulties may arise. The knitting was carried out in the Textilhögskolan in Borås machine hall on a flat knitting machine, a STOLL CMS822 HP knit and wear. The paper yarn used came exclusively from OJO+ Fibers and was made from pulp from the manilla plant. Two bindings were knitted, one mesh and one with floatations. The mesh binding was knitted in multiple variations, yarn of different yarn numbers and numbers of ingoing yarns. The most important parameters for knitting on industrial machines turned out to be the strength of the yarn, stiffness and gauge of the machine. A visual assessment was carried out after two separate production reviews and determined which knits were suitable to proceed to a tensile test. The standard used for tensile tests was (SS-EN ISO 13934-1:2013) on a Tinius Olsen H10KT (Elastocon). Five specimens of each knit were tested, first in the dry state and then in the wet state. A variance analysis compared the data from the tensile test, partly between the different constructions and between dry and wet samples within each group. The result shows a large spread within the data material, which cannot determine with certainty any conclusions about which construction is the strongest. The main reason for this spread is necessary deviations from the standard and the fact that (SS-EN ISO 13934-1:2013) is mainly for woven goods, not knitted ones. Two mesh constructions demonstrated a significant difference in results between the wet and dry samples. A weak tendency showed wet samples withstanding higher stress than dry ones, which could be a solution to increase the strength of the yarn while knitting.