Mesophilic Microorganisms Research Articles

EFFECT OF PULSED ELECTRIC FIELD (PEF) AND CRYOCONCENTRATION (c) IN AQUEOUS EXTRACTS OF MAQUI (Aristotelia chilensis (Mol.) Stuntz) AND CALAFATE (Berberis microphylla G.) ON PHYSICOCHEMICAL PROPERTIES, MICROBIOLOGICAL QUALITY, AND BIOACTIVE COMPOUNDS

The objective of this study was to evaluate the effect of PEF treatment followed by cryoconcentration (c) in aqueous extracts of maqui (Aristotelia chilensis (Mol.) Stuntz) and calafate (Berberis microphylla G.) on their physicochemical properties, microbiological quality, and bioactive compounds. Extracts of maqui and calafate were obtained by aqueous extraction of water-soluble compounds, and then samples were treated by PEF (10kV/cm, 70Hz and a pulse width of 10 µs) and pasteurization (90°C/30s); untreated samples were used as controls. The treated extracts were cryoconcentrated using centrifugation-filtration, and the cryoconcentration parameters included separation efficiency (EFF) and recovered solute (RS). Physicochemical properties were also evaluated, such as soluble solids (SS), titratable acidity (TTA), and viscosity (ƞ), as well as bioactive compound content: total polyphenols (TP), total anthocyanins (TA), total flavonoids (TF) and antioxidant capacity (AOXC). Microbiological quality was evaluated by the counts of the mesophilic aerobic microorganism (MAM) and molds and yeasts (M&Y). The results showed that the EFF of the solutes was higher than 95% in maqui and 97% in calafate. As expected, the cryoconcentration process increased TA, ƞ, and SS content. It also significantly increased (p<0.05) in TP, TF, TA, and AOXC content.The microbiological results showed that PEF treatment, together with cryoconcentration and refrigerated storage, maintained the microbiological quality of maqui cryoconcentrates for more than 50 days, whereas in calafate cryoconcentrates, it was maintained for ~20 days. Moreover, the physicochemical parameters and bioactive compounds of both cryoconcentrates remained stable during the refrigerated storage period.These results demonstrate that the combined use of PEF with cryconcentration seems to be a good option for microbiological and physiochemical stabilization of fruit juices with a high AOXC and for increasing the content of bioactive compounds.

Microbiological Quality of Coconut Water Sold in the Grande Vitória Region, Brazil, and Phenogenotypic Antimicrobial Resistance of Associated Enterobacteria.

This study aimed to evaluate the microbiological quality of coconut water sold from street carts equipped with cooling coils or refrigerated at bakeries in the Grande Vitória Region, Brazil. Additionally, it assessed the phenotypic and genotypic antimicrobial resistance profiles of isolated enterobacteria. The results indicated that coconut water sold at street carts had lower microbiological quality compared to refrigerated samples, as evidenced by significantly higher counts of mesophilic microorganisms. Using MALDI-TOF, the following opportunistic pathogens were identified: Citrobacter freundii, Enterobacter bugandensis, E. kobei, E. roggenkampii, Klebsiella pneumoniae, and Kluyvera ascorbata. Three isolates-E. bugandensis, K. pneumoniae, and K. ascorbata-were classified as multidrug-resistant (MDR). Widespread resistance to β-lactams and cephalosporins was detected, and some isolates were resistant to quinolones, nitrofurans, and phosphonic acids. The gene blaCTX-M-2 was detected in C. freundii, E. bugandensis, E. kobei, and K. ascorbata. However, genes blaNDM, blaKPC, blaCMY-1, and blaCMY-2 were not detected in any isolate. The findings underscore the need to enhance good manufacturing practices in this sector to control the spread of antimicrobial resistance (AMR). To our knowledge, this is the first study documenting the presence of potentially pathogenic enterobacteria in coconut water samples and their associated phenotypic and genotypic AMR profiles.

Avaliação microbiológica de carne bovina comercializadas no Brasil e conhecimentos de consumidores sobre segurança de alimentos

Meat is highly perishable and is often associated with foodborne disease outbreaks. The risk associated with handling food at home is underestimated, as consumers generally associate foodborne disease outbreaks with food from food services. This study aimed to quantify Escherichia coli, coagulase-positive staphylococci, mesophilic aerobic bacteria, and Salmonella spp. in ground beef samples sold at commercial establishments in Pelotas, Rio Grande do Sul State, Brazil, and to evaluate the knowledge of food safety among consumers in the region. Microbiological analyses were performed on 70 ground beef samples, and the knowledge of 92 meat consumers was analyzed using an online questionnaire based on the World Health Organization (WHO) safe food guidelines. Fifty percent of the meat samples had aerobic mesophilic microorganism counts above the limit established by Brazilian legislation, indicating unacceptable food quality. Only two samples (2.86%) had counts of coagulase-positive staphylococci above those allowed by legislation. The consumer knowledge regarding food safety showed that items related to “cook thoroughly” and “keeping food at safe temperatures” had the lowest percentage of correct answers. Dissemination of information about temperatures that ensure food safety is essential for consumers, especially considering that even with high levels of contamination, most microorganisms are destroyed by heat.

A conventional hatchery vs “on-farm” hatching of broiler chickens in terms of microbiological and microclimatic conditions

“On-farm hatching” is one of the proposed alternatives to conventional hatchery-hatching. This solution reduces distress and improves the welfare of the chicks around the hatching period. Therefore, it seemed interesting to compare conventional hatchery and “on-farm” hatching in terms of microbiological and microclimatic conditions. Hatching eggs (Ross 308) were incubated in a commercial hatchery. The control group (HH, 683 eggs) hatched in a conventional hatcher, while the other eggs were transported into the experimental chicken-hall for on-farm hatching, and set in pens directly on litter (OL, 667 eggs) or plastic trays (OT, 678 eggs). One-day-old chicks were also placed in the experimental hall. Microclimatic parameters were controlled every 12 h. The microbiological status of the surface of the eggshells and the litter was assessed based on the total number of aerobic mesophilic microorganisms and also the selected individual genus/species of bacteria. The hatchability of HH was 96.4% in comparison to 93.9% and 95.8% for OL and OT, respectively (P > 0.05). On the other hand, 2.1% of the HH chicks were found injured/dead, while only 0.2–0.3% of the on-farm groups were. The total number of aerobic mesophilic microflora on the surface of as-hatched shells was 4.93 ± 0.629 log CFU/g in HH, while only 1.14 ± 0.995 and 1.93 ± 1.709 log CFU/g in OL and OT, respectively (P < 0.001). Similarly, the total count of bacteria in the litter in the on-farm hatched pens was 1.9-fold lower than in pens set with HH chicks (P < 0.001). In summary, on-farm hatching results in hatchability that is no worse than in a conventional hatcher, while the microbiological status of as-hatched eggshells and litter is significantly better. Therefore, on-farm hatching seems to provide appropriate environmental conditions for newly hatched chicks and poses no epizootic risk.

Transcriptomic profiling of haloarchaeal denitrification through RNA-Seq analysis.

Denitrification, a crucial biochemical pathway prevalent among haloarchaea in hypersaline ecosystems, has garnered considerable attention in recent years due to its ecological implications. Nevertheless, the underlying molecular mechanisms and genetic regulation governing this respiration/detoxification process in haloarchaea remain largely unexplored. In this study, RNA-sequencing was used to compare the transcriptomes of the haloarchaeon Haloferax mediterranei under oxic and denitrifying conditions, shedding light on the intricate metabolic alterations occurring within the cell, such as the accurate control of the metal homeostasis. Furthermore, the investigation identifies several genes encoding transcriptional regulators and potential accessory proteins with putative roles in denitrification. Among these are bacterioopsin-like transcriptional activators, proteins harboring a domain of unknown function (DUF2249), and cyanoglobin. In addition, the study delves into the genetic regulation of denitrification, finding a regulatory motif within promoter regions that activates numerous denitrification-related genes. This research serves as a starting point for future molecular biology studies in haloarchaea, offering a promising avenue to unravel the intricate mechanisms governing haloarchaeal denitrification, a pathway of paramount ecological importance.IMPORTANCEDenitrification, a fundamental process within the nitrogen cycle, has been subject to extensive investigation due to its close association with anthropogenic activities, and its contribution to the global warming issue, mainly through the release of N2O emissions. Although our comprehension of denitrification and its implications is generally well established, most studies have been conducted in non-extreme environments with mesophilic microorganisms. Consequently, there is a significant knowledge gap concerning extremophilic denitrifiers, particularly those inhabiting hypersaline environments. The significance of this research was to delve into the process of haloarchaeal denitrification, utilizing the complete denitrifier haloarchaeon Haloferax mediterranei as a model organism. This research led to the analysis of the metabolic state of this microorganism under denitrifying conditions and the identification of regulatory signals and genes encoding proteins potentially involved in this pathway, serving as a valuable resource for future molecular studies.

Innovative use of chitosan/ZnO NPs bio-nanocomposites for sustainable antimicrobial food packaging of poultry meat

A novel nanocomposite was developed by integrating zinc oxide nanoparticles (ZnO NPs) into chitosan (CS) matrix and investigated for its impact on the quality and shelf life of refrigerated poultry meat over 11 days. Physicochemical properties including weight, pH, titratable acidity, color, thiobarbituric acid reactive substances assay, microbiological growth studies encompassed total psychotropic and mesophilic aerobic microorganisms, Enterobacteriaceae analyses, and zinc migration levels were conducted to determine the optimal nanocomposite concentration. Results revealed that bio-nanocomposite exhibited superior characteristics compared to chemogenic nanocomposite, chitosan, polyvinyl alcohol, and unwrapped meats. Bio-nanocomposite with reduced unsaturated lipid content extends poultry shelf life to 7 days in packaging, outperforming chemogenic-nanocomposites (5 days) and chitosan (4 days). This study proves that CS/ZnO NP nanocomposite is a promising active packaging material for meat, extending their shelf life without deteriorating its physicochemical characteristics and supporting sustainability, though further research on its toxicological properties is warranted.

Vermicompost: Significance and Benefits for Agriculture

Vermicomposting is defined as the process of biodegradation and stabilization of organic materials, facilitated by the collaborative efforts of earthworms and mesophilic microorganisms. The activity of earthworms in vermicomposting results in the production of nutrient-rich vermicompost. This organic amendment is abundant in macro and micronutrients, vitamins, growth hormones, as well as enzymes like proteases, amylases, lipase, cellulase, and chitinase. Additionally, vermicompost harbors a diverse community of immobilized microflora. Even after being excreted by the worms, the enzymes in vermicompost persist in their ability to decompose organic matter, facilitating continued breakdown and nutrient release. The utilization of vermicompost in agricultural production brings forth a multitude of beneficial effects. These include decreased water requirements for irrigation, reduced susceptibility to pest and termite attacks, suppression of weed growth, and enhanced seed germination rates, accelerated growth and development of seedlings, as well as increased yield of fruits per plant in vegetable crops and a higher number of seeds per year in cereal crops. These advantages highlight the positive impact of incorporating vermicompost into agricultural practices, fostering sustainable and productive farming systems. The combination of earthworms and vermicompost presents a valuable opportunity to enhance horticultural production in a sustainable manner, reducing reliance on agrochemical inputs. Despite the numerous benefits associated with vermicompost, its widespread implementation and adoption are still relatively limited. This review aims to raise awareness and promote the understanding of this valuable local soil amendment.

Nutrient Composition of Detoxified Oil Cake from Simarouba glauca

Vermicomposting is defined as the process of biodegradation and stabilization of organic materials, facilitated by the collaborative efforts of earthworms and mesophilic microorganisms. The activity of earthworms in vermicomposting results in the production of nutrient-rich vermicompost. This organic amendment is abundant in macro and micronutrients, vitamins, growth hormones, as well as enzymes like proteases, amylases, lipase, cellulase, and chitinase. Additionally, vermicompost harbors a diverse community of immobilized microflora. Even after being excreted by the worms, the enzymes in vermicompost persist in their ability to decompose organic matter, facilitating continued breakdown and nutrient release. The utilization of vermicompost in agricultural production brings forth a multitude of beneficial effects. These include decreased water requirements for irrigation, reduced susceptibility to pest and termite attacks, suppression of weed growth, and enhanced seed germination rates, accelerated growth and development of seedlings, as well as increased yield of fruits per plant in vegetable crops and a higher number of seeds per year in cereal crops. These advantages highlight the positive impact of incorporating vermicompost into agricultural practices, fostering sustainable and productive farming systems. The combination of earthworms and vermicompost presents a valuable opportunity to enhance horticultural production in a sustainable manner, reducing reliance on agrochemical inputs. Despite the numerous benefits associated with vermicompost, its widespread implementation and adoption are still relatively limited. This review aims to raise awareness and promote the understanding of this valuable local soil amendment.

Microbiological quality and safety of non‐treated fresh and squeezed juices from supermarkets in Lleida, Spain

SummaryThe growing consumption of untreated juices has increased the outbreaks related to Salmonella spp., Escherichia coli O157:H7 and Listeria monocytogenes. Although these pathogens are not in favourable conditions in fruit juices, cases of survival in acidic environments have been reported in fruit and vegetable juices. Thus, this study has evaluated the microbiological quality (total aerobic mesophilic microorganisms (TAM), moulds and yeasts, total coliforms (TC) and E. coli populations) and investigated the occurrence of foodborne pathogens (Salmonella spp. and L. monocytogenes) in 100 fresh (blended) and self‐service (monovarietal) untreated juices. Concerning the obtained results, pH was higher for fresh juices than for self‐service juices. The results showed great variability in TAM, moulds and yeasts and TC populations. For TAM, the results ranged from 1.7 to 7.4 log cfu mL−1. Values for moulds and yeasts, ranged from below detection limit (&lt;10 cfu mL−1) to 5.9 log cfu mL−1. And for TC, results went from below detection limit (&lt;1 cfu mL−1) to 4.4 log cfu mL−1. However, significant differences were only observed between the two types of samples in TC, being higher in fresh juices than in self‐service juices. For E. coli enumeration, all the samples were below the detection limit (1 cfu mL−1). Finally, no Salmonella spp. or L. monocytogenes were detected in 25 mL of sample. All analysed samples complied the requirements from European regulation.

Assessment of the risk of contamination of enteral nutrition bottles based on the simulation of home use conditions and hygiene procedures.

Home-prepared enteral formulations are supplied to patients through enteral nutrition bottles, via a gravity bag or other container, which may be inadequately sanitized and reused more times than recommended by the manufacturer. Such procedures increase the risk of contamination and can compromise the patient's clinical outcome. In light of this, the present study aimed to assess the risk of contamination of enteral nutrition bottles by simulating home use conditions and hygiene procedures. A simulation of bottle usage was conducted across the three categories of enteral nutrition (homemade enteral preparations, blended enteral preparations, and commercial enteral formulas) for 3 days, using three hygiene procedures reported by caregivers: use of detergent (DET); use of detergent and boiling water (DET+BW); and use of detergent and bleach (DET+BL). The microbiological contamination was determined by the analysis of aerobic mesophilic microorganisms. The bottles that were used for 3 days, regardless of the enteral nutrition category, were within the acceptable limit for aerobic mesophilic microorganisms (between <4 and 8.0 colony-forming units [CFU]/cm2) when sanitized using the DET+BW and DET+BL procedures. The enteral nutrition bottles, when cleaned using the DET procedure during the 3 days of usage, showed low microbial contamination (between <4 and 3.0 CFU/cm2) in blended preparation and commercial formula only. Thus, regardless of the enteral nutrition category, we found that the bottles can be used for 3 days, as long as the DET+BW or DET+BL hygiene procedure is applied and safe food handling measures are adopted.

Incidence of Vibrio parahaemolyticus Coryphaena Hippurus (dorado fish) and Thunnus alalunga (albacore fish) sold in high-demand markets in Guayaquil City

Foodborne diseases affect around 600 million people in the world. In Ecuador, the Ministry of Public Health (MSP) reported 12,203 cases of food poisoning caused mainly by Salmonella species, hepatitis virus or other pathogenic microorganisms in 2019. However, there are no reports of diseases caused by Vibrio species in Ecuador. The present study assessed the presence of V. parahaemolyticus, mesophilic aerobics, total coliforms and E. coli. Samples of Coryphaena hippurus (dorado fish) and Thunnus alalunga (albacore fish) in 3 different markets in the city of Guayaquil, Ecuador. As a result, Vibrio parahaemolyticus was not found in any of the 60 samples analyzed. In contrast, the E. coli levels met the requirements established in the INEN 183 - 2013 Standard norm. All samples from Market 1 were within the acceptance range regarding mesophilic aerobic levels. However, high mesophilic aerobic levels were obtained in 60% of the albacore samples and 50% of the dorado samples from this market. In the same way, 40% of the albacore and 100% of Dorado samples from market 3 were high in mesophilic microorganisms. However, the mesophilic aerobic analyses revealed safer levels in samples from market 1 than in markets 2 and 3, according to the NTE INEN. 183:2013. Keywords: Foodborne diseases1, fish2, Albacore3, E coli4, mesophilic aerobics5, Dorado6.

Incidence of Vibrio parahaemolyticus Coryphaena hippurus (dorado fish) and Thunnus alalunga (albacore fish) sold in high-demand markets in Guayaquil City

Foodborne diseases affect around 600 million people in the world. In Ecuador, the Ministry of Public Health (MSP) reported 12,203 cases of food poisoning caused mainly by Salmonella species, hepatitis virus or other pathogenic microorganisms in 2019. However, there are no reports of diseases caused by Vibrio species in Ecuador. The present study assessed the presence of V. parahaemolyticus, mesophilic aerobics, total coliforms and E. coli. Samples of Coryphaena hippurus (dorado fish) and Thunnus alalunga (albacore fish) in 3 different markets in the city of Guayaquil, Ecuador. As a result, Vibrio parahaemolyticus was not found in any of the 60 samples analyzed. In contrast, the E. coli levels met the requirements established in the INEN 183 - 2013 Standard norm. All samples from Market 1 were within the acceptance range regarding mesophilic aerobic levels. However, high mesophilic aerobic levels were obtained in 60% of the albacore samples and 50% of the dorado samples from this market. In the same way, 40% of the albacore and 100% of Dorado samples from market 3 were high in mesophilic microorganisms. However, the mesophilic aerobic analyses revealed safer levels in samples from market 1 than in markets 2 and 3, according to the NTE INEN. 183:2013. Keywords: Foodborne diseases1 , fish2 , Albacore3 , E coli4 , mesophilic aerobics5 , Dorado6

Inhibition of Salmonella enteritidis in homemade mayonnaise using oregano essential oil (Origanum vulgare)

The potential of oregano essential oil (OEO) as a natural antimicrobial agent to mitigate Salmonella spp. contamination in homemade mayonnaise made from raw eggs should be explored. This study aimed to assess the viability of Salmonella Enteritidis in homemade mayonnaise supplemented with OEO while also examining key quality parameters, including pH, titratable acidity, and the count of mesophilic aerobic microorganisms. In vitro experiments determined the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of OEO against two strains of Salmonella Enteritidis and one of Salmonella Typhimurium. Subsequently, homemade mayonnaise, intentionally contaminated with a Salmonella Enteritidis strain, was prepared, and OEO was added at concentrations of 0.5% and 1.0%. Bacterial plate counts for Salmonella spp. and mesophilic microorganisms, as well as acidity levels, were assessed at 0, 4, 8, and 24 hours of incubation at 30°C. The results indicated the in vitro efficacy of OEO, with an MIC of 0.5% and an MBC of 0.0625% against all strains. However, in homemade mayonnaise, Salmonella counts averaged 6.0 log CFU/g over the 24 hours at 30°C. Mesophilic microorganism counts also averaged 6.0 log CFU/g over 24 hours, similar to those of Salmonella. The pH values ranged from 4.5 to 5.1, and acidity levels remained between 0.31% and 0.39% throughout the 24 hours. In conclusion, oregano essential oil exhibited a bacteriostatic effect, effectively limiting the growth of Salmonella Enteritidis in homemade mayonnaise at the evaluated concentrations and time intervals.

Assessing the Microbial Quality of Shrimp (Xiphonaeus kroyeri) and Mussels (Perna perna) Illegally Sold in the Vitória Region, Brazil, and Investigating the Antimicrobial Resistance of Escherichia coli Isolates.

The consumption of seafood is crucial for food security, but poor hygiene along the food production chain can result in low microbiological quality, posing significant risks for public health and seafood quality. Thus, this study aimed to assess the microbiological quality and antimicrobial sensitivity of E. coli from 69 samples of illegally marketed shrimp and mussels in the Vitória Region, Brazil. These foods exhibited poor microbiological quality due to high counts of mesophilic, psychrotrophic, and enterobacteria microorganisms. While this issue is widespread in this area, shrimp samples displayed higher microbial counts compared to mussels, and fresh mussels had elevated counts of enterobacteria compared to frozen ones. Among the 10 E. coli isolates, none carried the genes blaCTX-M-1, blaCTX-M-2, blaCTX-M-3, blaCTX-M-15, mcr-1, mcr-2, mcr-3, mcr-4, and tet, associated with antibiotic resistance. Phenotypical resistance to tetracycline and fosfomycin was not observed in any isolate, while only 20% demonstrated resistance to ciprofloxacin. Regarding ampicillin and amoxicillin with clavulanic acid, 60% of isolates were resistant, 10% showed intermediate susceptibility, and 30% were sensitive. One isolate was considered simultaneously resistant to β-lactams and quinolones, and none were conserved as ESBL producers. These findings highlight the inherent risks to local public health that arise from consuming improperly prepared seafood in this area.

Microbiological characteristics of hard cheese with flax seeds

Highly nutritious dairy products such as hard cheeses are considered a good source of protein, fats, mineral substances, and vitamins and are consumed in significant quantities. At the same time, the disadvantages of cheeses include the presence of a large amount of saturated fatty acids in their composition, which are associated with the development of cardiovascular diseases. Therefore, modifying the composition of fatty acids in hard cheese by increasing the content of unsaturated fatty acids and reducing the amount of saturated fatty acids is extremely important for consumers' health. This research aimed to determine the dynamics of microbiological indicators in the ripening technology of hard rennet cheese with different contents of flax seeds as a source of omega-3 fatty acids. The technology of hard rennet cheese with 3-5% flax seed content was investigated. A 1.3 times higher content of lactic acid microflora was found in samples of hard cheese with 5% flax seeds during the first 10 days of ripening compared to the control sample of cheese. On the 60th day of ripening of cheese with a content of 5% flax seeds, the number of lactic acid bacteria was 9.4 ±0.3×109 CFU/g, and in the control cheese – 7.8 ±0.3×109 CFU/g. During the production and ripening of cheese with different content of flax seeds, no exceedance of normative values was found for the number of Enterobacteriaceae and Staphylococcus aureus bacteria. A method (washing the seeds in a sodium bicarbonate solution and drying at a temperature of 95 ±1 for 20 min) of processing flax seeds before adding them to the cheese mass was proposed, which reduced the number of mesophilic microorganisms by approximately 200 times to 3.9 ±0.1×101 CFU/ g, fungi by 160 times to 0.3 ±0.1×101 CFU/g and aerobic mesophilic bacilli by 78 times to 1.1 ±0.1×101 CFU/g. Therefore, the developed hard rennet cheese with flax seeds can be consumed as an additional source of omega-3 fatty acids and dietary fiber.

Microbiological quality of raw milk: community expansion tanks in Alagoas

Milk is a highly nutritious food consumed by a large part of the population, and due to its nutritional composition, its quality can be altered by the amount of microorganisms present. The objective of this study was to evaluate the microbiological quality of raw milk from community expansion tanks in the state of Alagoas. A total of 160 milk samples were aseptically collected from the three mesoregions of the state for microbiological analysis. It was observed that 10.83% (13/120) of the samples had Staphylococcus coagulase-positive counts lower than 105 CFU/mL, and 10.83% (13/120) had counts higher than 105 CFU/mL. For coliforms, 18.8% (30/160) were found to have counts less than 1.1×103 MPN/mL, while 81.2% (130/160) of the samples had values higher than 1.1×103 MPN/mL. No Salmonella spp. or Listeria spp. were found in any of the samples. Aeromonas spp. was found in 28.7% (46/160) of the samples. For mesophilic microorganisms, 15% (24/160) of the samples were within the standard required by legislation, while 85% (136/160) were outside the established limit of up to 6×105 CFU/mL. Psychrotrophic microorganism counts were higher than 5×106 CFU/mL in 41.9% (67/160) of the samples analyzed. It was concluded from this study that the high microorganism counts in the analyzed milk and the inadequate temperature of the tanks at the time of collection can lead to the production of a low-quality product due to the deteriorative or pathogenic action of the microorganism. Therefore, the implementation of good practices during milking, transportation, and storage of refrigerated raw milk is suggested to prevent contamination of the raw material, ensuring a product with certified quality.

Efeito do óleo essencial de Mentha piperita na conservação de carne refrigerada do peixe híbrido tambatinga

Abstract The search for safer foods has led to increased research attention to discover natural alternatives to synthetic additives that are used in the food industry. Natural preservatives, such as essential oils (EOs) from plants, could increase fish conservation and even positively affect human health. Therefore, the objective of the study was to evaluate the effect of Mentha piperita EO on the physicochemical characteristics and concentration of microorganisms in chilled tambatinga (Colossoma macropomum × Piaractus brachypomum) meat. Mentha piperita EO was prepared at three concentrations (0%, 0.25% and 0.50%) in a solution containing distilled water, propylene glycol and Tween. The meat samples remained immersed in this solution for 60 min; then, they were packed in plastic packages and stored under refrigeration (± 0.4 °C) for 14 days. During this storage, pH, total volatile nitrogenous bases (TVB-N), peroxides, thiobarbituric acid reactive substances (TBARS) and counts of strict and facultative aerobic mesophilic microorganisms were determined. The major constituents found in M. piperita EO were geranial (32.28%), neral (18.64%) and geranic acid (6.98%). None of the EO concentrations affected TVB-N, but there were some changes to the pH. Both 0.25% and 0.50% EO reduced the formation of peroxides and TBARS. The growth of microorganisms was reduced by treatment with 0.50% EO. Based on the findings, 0.50% EO was more effective in reducing the deterioration of meat kept refrigerated for up to 14 days.

Modifiye atmosfer ile paketlemenin etli mantının raf ömrü ve kalite özelliklerine etkisi

This study aimed to evaluate the effects of modified atmosphere packaging on the shelf-life and quality characteristics of mantı (a meat-filled pasta product) stored in refrigerator conditions. In this direction, mantı, whose humidity value is reduced to 34% with the pre-drying process, were packaged with different gas mixtures (ambient air, 80% CO2 + 20% N2, 60% CO2 + 40% N2, 40% CO2 + 60% N2, 20% O2 + 40% CO2 + 40% N2) and kept in cold storage for 90 days. In this process, mantı samples were analysed regarding physico-chemical, microbiological, colour and sensory parameters. According to the findings, Escherichia coli, sulfide-reducing anaerobic bacteria and Salmonella spp. were not detected. While total aerobic mesophilic microorganism and mould yeast counts increased throughout storage, they were lowest in packages containing 80% CO2. The high count of microorganisms in the samples packaged with ambient air also showed parallelism with the lipid oxidation values, causing the products to remain below acceptable sensory levels starting from the 60th day of storage. In the modified atmosphere packaging application, the increased amount of carbon dioxide in the package ensured that the texture and flavour properties of the mantı were preserved close to the first day during their shelf life. As a result, the modified atmosphere packaging application preserved the quality characteristics of mantı for a long time, increased their stay in the aisle and allowed them to be acceptable to consumers. While the protective effect increased, especially with the increasing amount of CO2 in the gas composition, the product's sensory properties were also preserved during storage, and economic losses could be prevented.

Assessment of the microbiological quality and heavy metal risk in vegetable species marketed in outdoor fairs

The objective of this study was to evaluate the possible health risks associated with the content of heavy metals and microorganisms in the consumption of watercress, lettuce, lemon balm and taraxaco. The products were purchased in several markets in the city of Quito. In this study, the products marketed in the north and center of the town showed better size characteristics, while the soluble solids, pH and ash showed no definite behavior. In addition, due to the volcanic origin of the Ecuadorian soils in which the samples under study were grown, it could influence the lead content that varied between 0.02 ppm (taraxacum, lemon balm and lettuce) up to 2.60 ppm (watercress). This value exceeded the maximum limit allowed by the CODEX, becoming a health risk. In addition, the microbial quality of the different species under study showed high contamination with mesophilic aerobic microorganisms and parasites. These results provide valuable information that could finance food safety decisions by the government to protect health and improve the quality of life of the people of Quito. Keywords: food safety, mesophilic aerobic, parasites, lead, Cadmium

The Effect of Fruit and Berry Pomaces on the Growth Dynamics of Microorganisms and Sensory Properties of Marinated Rainbow Trout.

Plant pomaces in suitable forms (powders, extracts) can be used in foods of animal origin to increase the nutritional value and safety of these foods. In the present study, water extracts of apple, black currant, rhubarb and tomato pomaces were used in fish marinade solutions to evaluate their effect on the growth dynamics of microorganisms and the growth potential of Listeria monocytogenes by challenge testing. The results showed that mesophilic aerobic microorganisms, Pseudomonas spp., yeasts and moulds remained at acceptable levels throughout the predetermined storage period. The challenge test results showed that the overall growth potential of L. monocytogenes in all marinated rainbow trout samples remained at ≤0.5 log10 cfu/g during the study period, and none of the marinated fish samples supported the growth of L. monocytogenes. In addition, the effect of fruit and berry pomaces on the sensory properties of marinated rainbow trout samples was evaluated. The results revealed that it is possible to effectively use fruit and berry pomaces in marinated fish products, ensuring food safety, high microbiological quality, acceptable sensory characteristics and a sufficiently long shelf life of the products.