Browsing by Author "Macieira, Ariana"
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- A case study on the microbiological consequences of short supply chains in high-income countries—the consequences of good handling practices (GHPs) in vegetable outlets in PortugalPublication . Macieira, Ariana; Brandão, Teresa R. S.; Teixeira, PaulaVegetables are commodities frequently sold in local markets and have been associated with foodborne outbreaks in short and local supply outlets worldwide. These outbreaks could potentially be mitigated through the implementation of good handling practices (GHPs) at points of sale. Numerous studies have assessed microbiological contamination in small-scale vegetable outlets in developing countries. In contrast, research on these risks in developed countries is comparatively scarce. However, with the increasing demand for vegetables, along with the increasing popularity of local markets, there is potential for an increase in foodborne outbreaks in developed countries. This study aimed to perform a microbiological assessment in local and short supply chain outlets of farmers in Portugal, as a case study, and to observe behaviors regarding GHPs in these outlets. The study was performed before and after the implementation of improved GHPs. This research employed quantitative analysis to measure the microbial load on vegetables, bench surfaces, and vendors’ hands. Additionally, a qualitative analysis was conducted to understand farmers’ behavior regarding GHPs using observational methods. Microbial hazards were detected in vegetables, on surfaces, and on hands both before and after the implementation of these practices, although the implementation of GHPs reduced the number of contaminations potentially associated with the practices used at the outlets. The results of this study highlight the importance of implementing GHPs in local and short supply chain markets for vegetables and fruits in developed countries, not only to protect consumers’ health, but also the farmers’ businesses.
- Concentrated autochthonous culture to be used on the production of safe meat productsPublication . Denisi, Federico; Sartori, Filippo; Barbosa, Joana; Albano, Helena; Macieira, Ariana; Teixeira, Paula
- Environmental and food safety assessment of pre-harvest activities in local small-scale fruit and vegetable farms in Northwest PortugalPublication . Macieira, Ariana; Fernandes, Virgínia Cruz; Brandão, Teresa R. S.; Delerue-Matos, Cristina; Teixeira, PaulaThe popularity of small-scale and local fruit and vegetable production has increased in recent years due to perceived economic, environmental, and social benefits. However, these operations face contamination risks that both consumers and small-scale producers may underestimate. The present study aimed to assess the microbiological and chemical hazards on fruit, vegetables, soil, and water samples from small-scale farms in north-western Portugal during pre-harvest activities. Additionally, the study investigated farmers’ non-compliance with food safety regulations and good agricultural practices (GAPs), exploring how their behaviour might contribute to the identified hazards. A before-and-after analysis of non-compliant behaviours was conducted to determine the impact of training on improving food safety practices. The analysis identified the presence of pathogenic bacteria, pesticides, flame retardant residues, nitrates, and heavy metals. Lead (Pb) concentrations exceeded EU limits in organic carrots from one producer (0.156 ± 0.043 mg/kg) and in chard from another (0.450 ± 0.126 mg/kg). Cadmium (Cd) levels were also above regulatory thresholds in bell peppers (0.023 ± 0.009 mg/kg) and organic tomatoes (0.026 ± 0.015 mg/kg) from two different producers. Elevated levels of heavy metals were detected in irrigation water from two sites, with zinc (Zn) at 0.2503 ± 0.0075 mg/L and Pb at 0.0218 ± 0.0073 mg/L. Among food samples, the most prevalent microorganisms were Pseudomonas spp. (88.2%), Bacillus cereus (76.5%), and aerobic mesophilic bacteria (100%). Phosphorus flame retardants (PFRs), particularly tris(2-butoxyethyl) phosphate (TBEP), were detected in all food and soil samples. Some EU-banned pesticides were detected in food and soil samples, but at levels below the maximum residue limits (MRLs). Chlorpyrifos (35.3%) and p,p’-DDD (23.5%) were the most detected pesticides in food samples. After the training, GAP behaviour improved, particularly that related to hygiene. However, issues related to record-keeping and soil and water analyses persisted, indicating ongoing challenges in achieving full compliance.
- Evaluation of a bacteriocinogenic Lactobacillus plantarum strain on the microbiological characteristics of “Alheira de Vitela”Publication . Macieira, Ariana; Albano, Helena; Pinto, Miguel; Linheiro, Raquel; Barbosa, Joana; Teixeira, PaulaLactic Acid Bacteria (LAB) and their bacteriocins can be successfully used as natural preservatives in meat products. This work aimed to investigate the effect of fresh and lyophilized starter cultures of an autochthonous bacteriocinogenic LAB strain (Lactobacillus plantarum ST153Ch: bac + culture) on the microbiological characteristics of “Alheira”, a traditional Portuguese smoked product. “Alheira” with the addition of fresh or lyophilized culture (ca. 108 cfu/g) and “Alheira” control (no bacteriocinogenic culture added) were produced by an industrial meat company. The antilisterial activity of this culture in this food matrix was investigated, with some samples being inoculated with Listeria monocytogenes (ca. 105 cfu/g). Detection of L. monocytogenes, Salmonella spp., sulphite reducing clostridia, Yersinia enterocolitica and enumeration of L. monocytogenes, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Enterobacteriaceae, lactic acid bacteria, yeasts and moulds were performed immediately after production and at 3, 7, 15, 21, 28, 60 and 90 days of storage at 4 ℃, according to ISO methodologies. Also, a 16S rRNA Gene Analysis was performed of the microbial communities of “Alheira” with and without the lyophilized bacteriocinogenic culture. Pathogenic and indicator organisms were not detected or were below acceptable levels in all samples. LAB counts increased during storage and reached similar values after 15 days (ca. 1010 cfu/g) in all samples. There was a clear trend for a higher reduction of L. monocytogenes in the presence of the bioprotective culture, more pronounced during the initial 15 days of storage. From the analysis of the microbial communities of samples of “Alheiras” at different stages of fermentation, Leuconostocaceae and Lactobacillaceae predominated in all the samples and Lactobacillus was the genus more prevalent in “Alheiras” after 60 days of storage with the addition of bacteriocinogenic culture.
- Food safety in local farming of fruits and vegetablesPublication . Macieira, Ariana; Barbosa, Joana; Teixeira, PaulaThe world’s population will be around 9 billion people by 2050. Humans need to feed in order to survive and thus the high demographic growth may impact the sustainability of our food systems. Sustainable food production practices such as local farming have been explored. Consumption of vegetables and fruits has been increasing due to their health benefits, but this increase is also related to a significant number of foodborne outbreaks. Foodborne outbreaks pose a threat to public health and the economy on a local and national scale. Food safety begins on the farm and proceeds over the supply chain. Thus, to provide safe products, food producers must follow specific procedures to avoid food hazards along the supply chain. This work aimed to present the importance of food safety in vegetables and fruits in local farming, as this form of production and consumption has increased in several countries of the northern hemisphere and as these are considered a form of providing more sustainable food products.
- Natural antimicrobial agents as an alternative to chemical antimicrobials in food preservationPublication . Gomes, Joana; Barbosa, Joana; Macieira, Ariana; Teixeira, PaulaIntroduction: Microbiological quality of food is of considerable concern to the food industry, since the activity of microorganisms can cause deterioration and, more seriously, affect the health of consumers [1]. Therefore, chemical additives are added to most of the foods with the purpose of maintaining certain properties or prolonging their shelf life [2]. However, there are several health-related problems associated with the use of these additives. Due to the problem of demonstrated or potential toxicity to the consumers, the number of chemical compounds allowed as food preservatives is limited [3]. Although, currently, most preservatives have no side effects and are classified as safe, there have been problems with the safety of some of these chemicals. The objective of this work was to determine the minimum inhibitory concentrations of three natural antimicrobial agents (ethanolic extract of propolis, chitosan and nisin) against 32 microorganisms (15 Gram-positive and 15 Gram-negative bacteria and two fungi) in order to compare with the minimum inhibitory concentrations of the chemical compound sodium nitrite, alone and in combination with sodium chloride. The inhibition of microorganisms was also tested at different pH values and temperatures of incubation to simulate the presence of the pathogens in different foods stored at different conditions. Conclusions: The natural compounds tested had greater inhibitory effect against the various microorganisms compared with the sodium nitrite alone and in combination with sodium chloride, in the different conditions of pH and temperature. Chitosan at 0.65% (w/v) inhibited most of the tested microorganisms. At 10 mg/mL of propolis, fungi, most of the Gram-positive and some of the Gram-negative bacteria were inhibited. At 25 μg/mL of nisin it was possible to inhibit most of the Gram-positives. Sodium nitrite, individually or in combination with sodium chloride, did not inhibit most microorganisms. The minimum inhibitory concentrations of several microorganisms were different depending on the methodology. With these in vitro results, it seems that the natural compounds investigated are good alternatives to chemical antimicrobials used in food production.
- Production of an antilisterial medium to be used in the industry of portuguese tradicional meat productsPublication . Macieira, Ariana; Barbosa, Joana; Albano, Helena; Teixeira, Paula
- Production of an antilisterial medium to be used in the industry of Portuguese traditional meat productsPublication . Macieira, Ariana; Barbosa, Joana; Albano, Helena; Morais, Alcina M. M. B.; Teixeira, PaulaIntroduction and Objective: Listeria monocytogenes is a great concern in the industry of Portuguese traditional meat products. Bacteriocins, produced by lactic acid bacteria (LAB) are of great importance in order to face this concern. The reason for that is because some bacteriocins have demonstrated antimicrobial activity against L. monocytogenes and do not alter the organoleptic characteristics of the products (1). Although MRS broth can fill some fastidious growth requirements of many LAB, it cannot be used in the food industry, not only because it is very expensive, when used for large-scale commercial applications, but also, it contains constituents not approved in food production (2). The objective of this study was to seek for a food grade medium that could promote growth of an autochthonous strain of Lactobacillus and production of bacteriocin active against L. monocytogenes. Conclusion: For the two medium, results showed that the maximum antilisterial activity was dependent on the target strains of L. monocytogenes. This food grade medium demonstrated to be a potential alternative to grow bacteriocinogenic Lactobacillus at industrial scale.
- Production of LAB bacteriocin in MRS medium and in a natural cereal medium with potential application in the food industryPublication . Macieira, Ariana; Maciel, Claudia; Albano, Helena; Morais, Alcina M M B; Teixeira, Paula