Browsing by Author "Barbosa, Joana Bastos"
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- Analysis of bacterial communities of squid and shrimp skewers after immersion in a red wine vinegar-based solutionPublication . Rezende, Lourenço Pinto de; Barbosa, Joana Bastos; Vaz-Moreira, Ivone; Teixeira, PaulaSeafood is a highly nutritious and essential component of a healthy diet.1 However, due to its perishable nature, seafood products have short shelf lives, leading to high prices and reduced desirability. In order to address this issue, various innovative techniques, such as High Pressure Processing and Ozonation, have been explored to extend the shelf life of seafood. While efficiency of such techniques varies, the cost of their application is usually high, increasing final price or reducing profit margins. Therefore, easier and cheaper, methods such as the pulverization or immersion of the product in antibacterial solutions are gaining popularity.2 To achieve the required bacterial inhibition and maintain an all-natural label, a seafood product, composed mainly of raw squid (Loligo duvauceli) andshrimp (Parapenaeopsis, Penaeus and Metapenaeus genus) was sprayed and immersed in a red wine vinegar-based solution. To perceive the efficiency of the treatment in the inhibition of unwanted spoilage bacteria, analysis of bacterial communities through sequencing of the 16S rRNA gene amplicons with NGS technologies (paired-end Illumina) was performed.
- Assessing antimicrobial efficacy on plastics and other non-porous surfaces: a closer look at studies using the ISO 22196:2011 standardPublication . Carvalho, Teresa Bento de; Barbosa, Joana Bastos; Teixeira, PaulaThe survival and spread of foodborne and nosocomial-associated bacteria through hightouch surfaces or contamination-prone sites, in either healthcare, domestic or food industry settings, are not always prevented by the employment of sanitary hygiene protocols. Antimicrobial surface coatings have emerged as a solution to eradicate pathogenic bacteria and prevent future infections and even outbreaks. Standardised antimicrobial testing methods play a crucial role in validating the effectiveness of these materials and enabling their application in real-life settings, providing reliable results that allow for comparison between antimicrobial surfaces while assuring end-use product safety. This review provides an insight into the studies using ISO 22196, which is considered the gold standard for antimicrobial surface coatings and examines the current state of the art in antimicrobial testing methods. It primarily focuses on identifying pitfalls and how even small variations in methods can lead to different results, affecting the assessment of the antimicrobial activity of a particular product.
- Bacteriological safety and quality of composted products from animal, urban or sewage sludge wastesPublication . Vaz-Moreira, Ivone; D’Arnese, Angelo; Knoll, Maurice; Teixeira, A. Margarida; Barbosa, Joana Bastos; Teixeira, Paula; Manaia, Célia M.Abstract: This study investigated the presence of culturable bacterial pathogens, and antibiotic resistance and associated genes (quantitative PCR) in commercially available composted products from animal excrements or manure (n=7), urban wastes (n=1) or (sewage sludge) (n=1). Metals quantification and 16S rRNA-based bacterial community composition analyses supported the results to infer potential risks to downstream environments (e.g., soils). Bacilli and Actinomycetes were the dominant bacterial classes in seven composts, while two were dominated by different classes of Pseudomonadota or the class Bacteroidia. Salmonella spp. was not detected in all composts, meeting recommended quality criteria, while Escherichia coli and Listeria monocytogenes were only detected in the sewage sludge compost. The antibiotic resistance genes ermB and ermF were detected in most of the composts, and the antibiotic resistance gene sul1 and the intI1 gene (proxy for antibiotic resistance recombination) in all composts in the range of 6-9 log gene copy number/g dry weight. Listeria spp. and the gene blaCTX-M were detected only in chicken/poultry composts suggesting increased risk. All composts, except the urban waste compost, presented at least one metal (zinc, copper, and/or cadmium) above the recommended value. The genes uidA, crAssphage, ermB and blaCTX-M were negatively correlated with the abundance of total heterotrophs and moisture content, and the genes intI1 and sul1 were negatively correlated with the concentration of the metals Cr, Ni and Pb. Overall, the urban waste compost presented the best quality, exhibiting the lowest antibiotic resistance load. These findings alert for the fact that composts may contribute to the dissemination of antibiotic resistance, highlighting the need of regular assessment. It is suggested that multiple factors, including the raw materials, may influence the safety of the final compost, and the knowledge of the variables affecting compost safety need to be thoroughly investigated and understood.
- Clean labelling sodium nitrite at pilot scale: in-situ reduction of nitrate from plant sources and its effects on the overall quality and safety of restructured cooked hamPublication . Carvalho, Teresa Bento de; Oliveira, Mónica; Gomes, Ana Maria; Monteiro, Maria João; Pintado, Manuela; Komora, Norton; Durães, Tiago; Nunes, Fernando M.; Cosme, Fernanda; Patarata, Luís; Brandão, Teresa R. S.; Barbosa, Joana Bastos; Teixeira, PaulaGrowing health and environmental concerns have increased demand for all-natural products, with a focus on clean labelling. Sodium nitrite is the most widely used additive in the meat industry because it imparts the typical cured flavour and colour to meat products and, most importantly, their microbiological safety. However, due to health concerns, the European Commission is proposing revised regulations to reduce nitrate and nitrite levels in meat products. As a result, the meat industry is actively seeking alternatives. This study explored the production of four cooked hams utilising nitrate-rich vegetable sources combined with two different nitrate-reducing commercial food cultures, alongside a control ham prepared with sodium nitrite (150 ppm). Microbiological, physico-chemical (pH, water activity, nitrate and nitrite concentration, lipid profile, lipid oxidation) and sensory (texture and colour profile) characterisation of the products was carried out. Challenge tests for Listeria mono- cytogenes, Clostridium sporogenes and Clostridium perfringens have been performed to assess the growth of path- ogens, if present in the products. Results revealed comparable microbiological and physico-chemical profiles across ham formulations, with minor differences observed in colour parameters for sample C. The sensory analysis showed that for the pilot ham formulations A and D, there were no significant differences in consumer perception compared to the control ham. In the challenge tests, L. monocytogenes levels were similar in both control and tested hams. There were no significant differences in C. sporogenes and C. perfringens counts at any temperature or between test and control samples. These results indicate that this technology has a potential future in the cured meat sector, as regulators mandate the reduction of added synthetic chemicals and consumers seek healthier and more natural ingredients in their daily diets.
- Development of alternative "clean label" proposal to the use of preservatives and other additives in meat productsPublication . Carvalho, Teresa Bento de; Komora, Norton; Barbosa, Joana Bastos; Teixeira, Paula
- Effectiveness and durability of a quaternary ammonium compounds-based surface coating to reduce surface contaminationPublication . Bento de Carvalho, Teresa; Barbosa, Joana Bastos; Teixeira, PaulaFoodborne diseases are of major concern as they have a significant impact on public health, both socially and economically. The occurrence of cross-contamination of food in household kitchens is a serious threat and the adoption of safe food practices is of paramount importance. This work aimed to study the effectiveness and durability of a commercial quaternary ammonium compound-based surface coating which, according to the manufacturer, retains its antimicrobial activity for 30 days, and is suitable for all types of hard surfaces for the prevention and/or control of cross-contamination. For that, its antimicrobial efficacy, killing contact time and durability on three different surfaces—polyvinyl chloride, glass, and stainless-steel—against three pathogens—Escherichia coli ATCC 25922, Acinetobacter baumannii ESB260 and Listeria monocytogenes Scott A—were tested according to the current antimicrobial treated surfaces efficacy test (ISO22196:2011). The results showed that the antimicrobial coating was effective against all pathogens with a reduction of >5.0 log CFU/cm2 in less than one minute for the three surfaces, but its durability was less than one week on all surfaces cleaned in the usual manner. Additionally, trace amounts (≤0.2 mg/kg) of the antimicrobial coating, which may migrate into food when contacting the surface, did not show cytotoxicity to human colorectal adenocarcinoma cells. The suggested antimicrobial coating has the potential to significantly reduce surface contamination, ensure surface disinfection and reduce the likelihood of cross-contamination in domestic kitchens, although it is less durable than suggested. The use of this technology in household settings is an attractive complement to the existing cleaning protocols and solutions that are already in place.
- Impact of different diets and starvation periods on microbial load of Tenebrio molitor larvaePublication . Pereira, Inês; Carvalho, Teresa Bento de; Soares, Luís; Ribeiro, Tiago; Esteves, Vasco; Barbosa, Joana Bastos; Teixeira, PaulaIntroduction: In a world facing an environmental crisis, the growth of the world's population coupled with an increasing demand for natural resources emphasizes the importance of adopting new dietary patterns based on health and sustainability (1). The consumption of edible insects (e.g. Tenebrio molitor) offers an alternative to animal protein sources, providing a sustainable food production cycle that ensures food security with minimal environmental impact (2). The main challenges in the T. molitor production industry are the selection of an appropriate feeding regime, as this affects the growth performance, nutritional profile and microbiota of the insect, and the processing steps required to commercialize mealworm larvae for human consumption. These steps have a direct impact on safety by allowing the gut contents to be discarded, thereby reducing the microbiological load and the presence of pathogenic microorganisms (3, 4). Typically, mealworm larvae are reared in a dry, starchy substrate supplemented by a water source, such as slices of vegetables or fruit. After being reared under optimal growth conditions, the larvae are sifted and then subjected to a fasting period of at least 24 hours, as required by law. This fasting process allows the intestinal contents to be discarded and limits the microbiological load, with the fasting period being a legal requirement of at least 24 hours (3, 4). Objective: This study aimed to analyze the microbiology of Tenebrio molitor larvae subjected to various feeding regimes (substrate with water, potato, carrot, or a fresh vegetable mix) and subsequently subjected to different starvations periods (0 hours, 24 hours, 48 hours and 72 hours). Discussion and conclusions: In general, the performance of starvation is dependent on the diet to which the larvae were subjected for each microbiological parameter evaluated. A positive result is considered when, for larvae subjected to the same diet, the counts of a given parameter at a given starvation period (24 h, 48 h, 72 h) are lower than those observed in the control without starvation (0h). This was observed only for: larvae A, for anaerobic Bacillus spores after 48h, and for yeasts after 72h; larvae B, for aerobic Bacillus spores and anaerobic Bacillus spores after 24 h ,48 h and 72 h and for molds after 24 h and 72h; larvae C, for Enterobacteria and yeasts after 24h and 72h; for aerobic Bacillus spores after 24h, 48h and 72h; and for anaerobic Bacillus spores after 24 h and 48h; larvae D, for TVC, LAB and anaerobic Bacillus spores after 24, 48h, 72h; for Enterococcus after 48 h and 72 h; for Enterococcus after 48h and 72h; for aerobic Bacillus spores after 24 h and 72 h; and for yeasts after 48h. Salmonella spp. and Listeria spp. were not detected in 10 g of each sample analysed. In conclusion, these results call into question the efficacy of fasting periods in reducing the microbial load of T. molitor larvae, as previously reported in other studies, and highlight the importance of heat treatments following fasting to ensure the food safety of the final product.
- Impact of novel clean label ham formulations on the human gut microbiotaPublication . Carvalho, Teresa Bento de; Barbosa, Joana Bastos; Carvalho, Nelson Mota de; Souza, Carla; Costa, Célia; Komora, Norton; Azevedo, Alexandra; Madureira, Ana Raquel; Teixeira, PaulaIntroduction: The influence of diet on the human gut microbiota has been the subject of much debate, particularly in relation to innovative products that are still considered novel. Dietary habits have a fundamental impact on the human gut microbiota, which explains the variations observed between individuals and over the course of a lifetime. The aim of this study was to evaluate the effect of four clean label ham formulations (Table 1) (without sodium nitrite and with natural nitrate sources combined with the addition of nitrate reducing cultures) on the human gut microbiota of potential consumers after in vitro digestion, according to the INFOGEST protocol, and colonic fermentation. Methods: DNA extraction from the stored pellets was carried out using the Invitrogen PureLink™ Microbiome DNA Purification Kit. 16S rRNA gene sequence data was processed with QIIME2 by Novogene UK; Quantification of fermentation metabolites, short-chained fatty acids and branched- chained fatty acids, by high-performance liquid chromatography (HPLC) from supernatant. The impact of each novel formulation and for a faecal inoculum control (Inoc) on the gut microbiota profile and fermentation metabolites (i.e., SCFAs) was assessed by next-generation sequencing (NGS) and high-performance liquid chromatography (HPLC), respectively. Results and discussion: Higher concentration of SCFA (Acetate + Butyrate + Propionate) after 48 h colonic fermentation were found for: D (65.96 mM) > A (63.36 mM) > E (59.35 mM) > C (58.64 mM) > B (57.22 mM) > Inoc (16.20 mM); Lowest SCFA concentrations were found for the inoculum control (Inoc), as expected, due to the lack of nutrients to promote bacterial fermentation over time. The most abundant phylum present were Bacillota and Pseudomonadota for all samples (A, B, C, D, E and Inoc) and all time points (0h, 24h and 48h); Higher relative abundance of Pseudomonadota was observed for all samples when compared to the inoculum control (Inoc); After fermentation, relative abundance of Bacteroidota is higher for the ham control sample (added sodium nitrite) than for the samples that are formulated with natural plant nitrate coupled with starter cultures. Conclusions: There were no discernible variations in SCFA levels or microbial populations during colonic fermentation between the new formulations and the conventional ham, indicating that the suggested clean label approach produced encouraging outcomes; Additional investigation should provide light on the endogenous production of volatile and non-volatile chemicals (nitrosamines) in vitro, their effects on the microbiota in the human gut, and any potential toxicity to human intestinal epithelial cells.
- Impact of red wine vinegar-based solution on bacterial communities of squid and shrimp skewers: a classic and genomic approachPublication . Rezende, Lourenço Pinto de; Barbosa, Joana Bastos; Carvalho, Teresa Bento de; Vaz-Moreira, Ivone; Monteiro, Maria João P.; Teixeira, PaulaSeafood is an essential component of a balanced and healthy diet, which increases its demand. However, its biological composition and high moisture content make these products extremely perishable. To prevent spoilage, and the consequent food waste and fnancial expenses throughout the seafood supply chain, new technologies have been successfully developed to inhibit bacterial growth, the main cause of seafood spoilage. This work aimed to test a shelf life extension technique for seafood skewers whilst maintaining an all-natural label using a fnancially feasible red wine vinegar treatment applied by immersion or pulverisation. Bacterial growth was monitored by classical methods and by 16S rRNA gene amplicon sequencing during the 5 days of storage. Immersion of samples in a vinegar-based solution efectively reduced Pseudomonas and Enterobacterales counts (by 2 log cfu/g), immediately after application and throughout storage. The overall structure and diversity of the bacterial community were analysed, and a strong reduction in bacterial diversity and impact on bacterial composition was observed immediately after immersion in the red wine vinegar solution. In untreated samples, Pseudomonadota (especially the Gammaproteobacteria class) was the principal phylum, whereas the microbiota of the treated samples was dominated by Bacillota (mainly the Bacilli class). Sensory analysis revealed a mild vinegar or vinaigrette favour in treated samples; however, these characteristics were not unpleasant. Although applying a vinegar-based solution by immersion promoted a signifcant reduction in the growth of spoilage bacteria during the frst days of storage, further tests are required to confrm the shelf life extension.
- In vitro colonic fermentation of clean label ham formulations: gut microbiota modulation and metabolite productionPublication . Carvalho, Teresa Bento de; Barbosa, Joana Bastos; Carvalho, Nelson Mota de; Komora, Norton; Carvalho, Fátima; Madureira, Ana Raquel; Teixeira, PaulaConsumer wishes for “clean label” products have prompted the rise of these products available in the market. With dietary choices directly influencing market trends, developing novel meat products with natural nitrate and nitrite alternatives is a sought-after premise. Cured meats like ham have been under scrutiny due to their potential harm to human health, having sodium nitrite been theorised to trigger dysbiosis of the gut microbiota and impair faecal short-chain fatty acids (SCFAs) production. Four novel ham formulations with a natural nitrate source coupled with nitrate-reducing starter cultures were subjected to an in vitro gastrointestinal digestion simulation (INFOGEST) and followed by in vitro colonic fermentation. The impact of each novel ham formulation on the gut microbiota and their fermentation metabolites, namely SCFAs, was assessed by quantitative Next Generation Sequencing and High-Performance Liquid Chromatography, respectively. No significant differences have been found for SCFAs levels or microbial communities throughout colonic fermentation. Further research should provide insight into how these alternatives can be associated with nitrosamine formation. The potential benefits of "clean label" alternatives need to be thoroughly demonstrated. While these solutions are often considered preferable to traditional nitrite-containing products, their implementation should be approached with caution. In addition to their antimicrobial efficacy and consumer acceptance, it is essential to assess their impact on product cost and compare their performance and health impact (positive or negative) with that of traditional nitrite formulations. Extensive research is needed to ensure that any move to "clean label" formulations is based on solid evidence rather than market trends.