This study aimed to evaluate technological (acidification, proteolysis, lipolysis, resistance to low pH, NaCl, and bile salts) and biopreservation (antimicrobial activity against foodborne pathogens) features of 1002 LAB by high throughput screening (HTS) methods. The LAB was isolated from 11 types of Brazilian artisanal cheeses (BAC) marketed in the main 5 producing regions. Remarkable intra-species variability in acidification rates have been found, which was most pronounced between isolates from Mina's artisanal cheeses, Caipira and Coalho cheeses. Lacticaseibacillus paracasei and Levilactobacillus brevis showed the fastest acidification rate; however, all isolates showed slower acidification rates than a lactococcal control strain (4.3 × lower). When testing inhibitory effects, > 75% of LAB isolates could inhibit the growth of Staphylococcus aureus ATCC 19095 and Listeria monocytogenes ATCC 7644. Two of these isolates, identified as Lactiplantibacillus plantarum and Lentilactobacillus buchneri, the sterile and neutral supernatants alone, were sufficient to inhibit L. monocytogenes growth. Principal component analysis (PCA) allowed the identification of functional groups based on proteolytic and lipolytic activity, osmotic stress resistance, and inhibition of L. monocytogenes. The type of cheese the isolates were recovered from influenced properties such as anti-listerial compounds and lipolytic enzyme production. The use of HTS and multivariate statistics allowed insights into a diverse set of LAB technological and biopreservation properties. These findings allow a profound knowledge of the heterogeneity of a large set of isolates, which can be further used to design starter cultures with varied and combined properties, such as biopreservation and technological features. Besides that, HTS makes it possible to analyze a vast panel of LAB strains, reducing costs and time within laboratory analysis, while avoiding the loss of information once all LAB are tested at the same time (differently from the traditional labor-intensive approach, in which a few numbers of strains is tested per time).
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Inoculation of maize silage with Lactobacillus buchneri (5 × 105 c.f.u. g-1 of maize silage) prior to ensiling results in the formation of aerobically stable silage. After 9 months, lactic acid bacterium counts are approximately 1010 c.f.u. g-1 in these treated silages. An important subpopulation (5.9 × 107 c.f.u. g-1) is able to degrade 1,2-propanediol, a fermentation product of L. buchneri, under anoxic conditions to 1-propanol and propionic acid. From this group of 1,2-propanediol-fermenting, facultatively anaerobic, heterofermentative lactobacilli, two rod-shaped isolates were purified and characterized. Comparative 16S rDNA sequence analysis revealed that the newly isolated bacteria have identical 16S rDNA sequences and belong phylogenetically to the L. buchneri group. DNA-DNA hybridizations, whole-cell protein fingerprinting and examination of phenotypic properties indicated that these two isolates represent a novel species, for which the name Lactobacillus diolivorans sp. nov. is proposed. The type strain is LMG 19667T ( = DSM 14421T).
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Docentonderzoeker Rob van Diepenbeek was een van de sprekers op de Intelligent Food processing & packaging Virtual Summit, een online platform waar foodprofessionals kunnen netwerken, ideeën en kennis uitwisselen en van elkaar leren waar het gaat om toekomst van ons voedsel. Rob ging onder meer in op de nauwe samenwerking van HAS Hogeschool met Food Tech Brainport in Helmond, een belangrijke experimenteerruimte als het gaat om het terugdringen van voedselverspilling en bij- en reststromen te verwaarden door middel van milde conservering en milde scheidingstechnieken. Veelbelovende productapplicatie-kansen en energiebesparingen kwamen aan bod.
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Plasmid-mediated dissemination of antibiotic resistance among fecal Enterobacteriaceae in natural ecosystems may contribute to the persistence of antibiotic resistance genes in anthropogenically impacted environments. Plasmid transfer frequencies measured under laboratory conditions might lead to overestimation of plasmid transfer potential in natural ecosystems. This study assessed differences in the conjugative transfer of an IncP-1 (pKJK5) plasmid to three natural Escherichia coli strains carrying extended-spectrum beta-lactamases, by filter mating. Matings were performed under optimal laboratory conditions (rich LB medium and 37°C) and environmentally relevant temperatures (25, 15 and 9°C) or nutrient regimes mimicking environmental conditions and limitations (synthetic wastewater and soil extract). Under optimal nutrient conditions and temperature, two recipients yielded high transfer frequencies (5 × 10–1) while the conjugation frequency of the third strain was 1000-fold lower. Decreasing mating temperatures to psychrophilic ranges led to lower transfer frequencies, albeit all three strains conjugated under all the tested temperatures. Low nutritive media caused significant decreases in transconjugants (−3 logs for synthetic wastewater; −6 logs for soil extract), where only one of the strains was able to produce detectable transconjugants. Collectively, this study highlights that despite less-than-optimal conditions, fecal organisms may transfer plasmids in the environment, but the transfer of pKJK5 between microorganisms is limited mainly by low nutrient conditions.
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Acne vulgaris is considered one of the most common medical skin conditions globally, affecting approximately 85% of individuals worldwide. While acne is most prevalent among adolescents between 15 to 24 years old, it is not uncommon in adults either. Acne addresses a number of different challenges, causing a multidimensional disease burden. These challenges include clinical sequelae, such as post inflammatory hyperpigmentation (PIH) and the chance of developing lifelong disfiguring scars, psychological aspects such as deficits in health related quality of life, chronicity of acne, economic factors, and treatment-related issues, such as antimicrobial resistance. The multidimensionality of the disease burden stipulates the importance of an effective and timely treatment in a well organised care system. Within the Netherlands, acne care provision is managed by several types of professional care givers, each approaching acne care from different angles: (I) general practitioners (GPs) who serve as ‘gatekeepers’ of healthcare within primary care; (II) dermatologists providing specialist medical care within secondary care; (III) dermal therapists, a non-physician medical professional with a bachelor’s degree, exclusively operating within the Australian and Dutch primary and secondary health care; and (IV) beauticians, mainly working within the cosmetology or wellness domain. However, despite the large variety in acne care services, many patients experience a delay between the onset of acne and receiving an effective treatment, or a prolonged use of care, which raises the question whether acne related care resources are being used in the most effective and (cost)efficient way. It is therefore necessary to gain insights into the organization and quality of Dutch acne health care beyond conventional guidelines and protocols. Exploring areas of care that may need improvement allow Dutch acne healthcare services to develop and improve the quality of acne care services in harmony with patient needs.
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Unwanted tomatoes represent ~20% of the European market, meaning that ~3 million metric tons of tomatoes are wasted every year. On a national scale, this translates to 7000 tons of tomato waste every year. Considering the challenge that food spillage represents worldwide and that the Netherlands wants to be circular by 2050, it is important to find a way to circularize these tomatoes back into the food chain. Moreover, tomatoes are the largest greenhouse crop in the Netherlands, which means that reducing the waste of this crop will positively and significantly affect the circularity and sustainability of the Dutch food system. A way to bring these tomatoes back into the food chain is through fermentation with lactic acid bacteria (LAB), which are already used in many food applications. In this project, we will assemble a unique new mix (co-culture) of LAB bacteria, which will lead to a stable fermented product with low sugar, low pH and a fresh taste, without compromising its nutritional value. This fermentation will prevent the contamination of the product with other microorganisms, providing the product with a prolonged shelf life, and will have a positive impact on the health of the consumers. Up until now, only non-fermented products have been produced from rejected tomatoes. This solution allows for an in-between product that can be used towards many different applications. This process will be upscaled to pilot scale with our consortium partners HAN BioCentre, Keep Food Simple, LLTB and Kramer B.V. The aim is to optimize the process and taste the end result of the different fermentations, so the end product is an attractive, circular, and tasty fermented tomato paste. These results will help to advance the circularity and sustainability of our food system, both at a national and European level.
