Percorrer por autor "Komora, N."
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- Characterization of clinical and food Listeria monocytogenes isolates with different antibiotic resistance patterns through simulated gastrointestinal tract conditions and environmental stressesPublication . Cunha, S.; Komora, N.; Magalhães, R.; Almeida, Gonçalo; Ferreira, V.; Teixeira, PaulaThirty-three Listeria monocytogenes isolates previously collected from two sources, food (n = 18) and human patients suffering from listeriosis (n = 15), with variable antibiotic susceptibility profiles (sensitive/resistant) to erythromycin, ciprofloxacin and nitrofurantoin, were studied for their ability to survive (i) the environmental stress provided by sequential conditions that simulate the digestive tract, and (ii) extreme pH values (1.5–12). The results showed a response that was only strain dependent. There were no variability in survival results based on type of stress (low or high pH), source (food or clinical), or sensitivity/resistance to antibiotics (p > 0.01). Some strains of L. monocytogenes are able to survive extreme acid and alkaline conditions, and conditions that mimic the sequential stressors found in the gastro-intestinal tract. The resistance to the antibiotics tested in this study by some L. monocytogenes strains did not confer any cross-protection to acid or alkaline stressors.
- Clean label alternatives to the use of nitrite in cooked ham: results of a pilot studyPublication . Carvalho, T. Bento de; Oliveira, M.; Komora, N.; Teixeira, P.Introduction: Environmental and health concerns over the use and consumption of artificial additives like nitrite have prompted consumer wishes and desire for “cleaner” products containing natural ingredients whose names they know and understand. Objectives: The aim of this work was to assess if natural sources of nitrate in combination with nitrate-reducing starter cultures would be good substitutes of chemical nitrite in cooked ham. Methodology: Four cooked hams, combining rich nitrate vegetable sources with two different nitrate- reducing commercial starter cultures were manufactured at pilot scale by Primor. Results and discussion: With the exception of Enterobacteriaceae, which were not found in the control ham, all other microbiological parameters were similar for the various hams. The challenge test showed that at abuse temperature, L. monocytogenes increased 1 to 2 log cycles when compared to storage at 4 ℃. The colour, texture, pH and aw values were similar for the four test hams and the control throughout storage (28 days). Conclusions: These preliminary results demonstrate the potential of using natural sources of nitrates combined with nitrated-reducing starters as a clean label alternative to the use of nitrite in cooked ham, maintaining microbiological safety and organoleptic properties.
- Comparison between semi-intensively and intensively grown beefPublication . Jesus, D.; Alcalá, L.; Komora, N.; Monteiro, M.J.; Gama, I.; Teixeira, R.F.M.; Pintado, M.
- In-situ conversion of natural sources of nitrate for clean labelling meat products: cooked ham case studyPublication . Carvalho, T. Bento de; Oliveira, M.; Komora, N.; Teixeira, P.Introduction: Clean labelling of meat products has emerged as a promising marketing trend in the industry. Ingredient lists with recognizable ingredients and minimal processing have been preferred by consumers in recent years, with increasing demand. Objectives: This study firstly aimed to assess the behaviour of three pathogens commonly associated with ham products throughout storage at refrigeration (4 ºC) and abuse (10 ºC) temperature. Secondly, sensory analysis to evaluate differences between hams was carried out. Results and discussion: When inoculated in the products, L. monocytogenes reached similar values in both control and the test hams. A 2-log difference was observed between the two storage temperatures, being that at 10 °C bacterial counts were higher. No differences between C. sporogenes and C. perfringens counts were observed for both temperatures and between test ham samples and control sample (p > 0.05). No differences between samples, except ham sample C, and control were found in sensory analysis, proving the promising commercial potential of the restructured hams. Conclusion: These results show the promising application of this technology in the meat industry, having in mind consumers wishes and demand for more nutritious and natural ingredients in day-to-day foods.
- Nutritional and sensory characterization of semi-intensively and intensively grown beefPublication . Jesus, D.; Voss, H-P; Monteiro, M. J.; Ramos, P.; Alcalá, L.; Gama, I.; Teixeira, R. F. M.; Domingos, T.; Komora, N.; Teixeira, P.; Pintado, M.
- Prevalence of staphylococcus aureus from nares and hands on health care professionals in a portuguese hospitalPublication . Castro, A.; Komora, N.; Ferreira, Vânia; Lira, A.; Mota, M.; Silva, Joana; Teixeira, PaulaAims: The main goal was to estimate the prevalence of methicillin-resistant Staphylococcus aureus on hands and in nose of health care professionals. Methods and Results: Detection of Staph. aureus on hands or in the nose of 169 individuals was performed. Nasal and hand carriage was found in 39 6 and in 8 9% respectively. About 17 2% of the individuals were carriers of methicillin-resistant Staph. aureus (MRSA) in the nose and 4 7% on hands. The majority of nasal MRSA were resistant to b-lactams, erythromycin and ciprofloxacin. All nasal MRSA were SCCmec type IV and Panton-Valentine leukocidin (PVL) negative. One MRSA isolated from hand was SCCmec type V. About 75 6% of MRSA isolates presented the same or closely related restriction patterns. Sixty per cent of Staph. aureus from hands and from noses from the same individual were the same strain. Conclusions: MRSA nasal carriage was high considering healthy health care professionals but in accordance with high level of MRSA infection in Portugal. Isolates recovered in this study seemed to be different from major clones previously isolated in other Portuguese hospitals. Significance and Impact of the Study: These findings may have implications on the knowledge of healthy health care workers as vehicles of MRSA infections among the community. Presence of several virulence factors may contribute to increased pathogenesis in case of infection.