Browsing by Author "Komora, Norton"
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- 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.
- Comparison between semi-intensively and intensively grown beefPublication . Jesus, Diva; Alcalá, Luís; Domingos, Tiago; Gama, Ivo; Komora, Norton; Monteiro, Maria João; Teixeira, Ricardo F. M.; Teixeira, Paula; Pintado, Manuela
- 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
- Evaluating the effectiveness of four preservatives in enhancing the shelf life and safety of meat analoguesPublication . Nunes, Maria J. M.; Escobar, Luis; Noronha, Lúcia; Cruz, Inês; Komora, Norton; Barbosa, Joana; Carvalho, Fátima; Teixeira, Paula
- Evaluating the efficacy of four preservatives against pathogenic bacteria in meat analoguesPublication . Nunes, Maria João; Escobar, Luís; Noronha, Lucia; Cruz, Maria Inês; Komora, Norton; Barbosa, Joana; Carvalho, Fátima; Teixeira, PaulaMeat products represent a large proportion of the human diet and can be included into the diet in a variety of ways. Recently, with changing consumer perceptions of sustainability, some food intolerances, and even animal welfare concerns, trends have emerged to reduce meat consumption. To achieve this, the industry has had to come up with vegan or vegetarian alternatives—meat analogues— “products that mimic meat in their functionality, bearing similar appearance, texture, and sensory attributes to meat”. Meat analogues typically include synthetic chemical preservatives in their formulation, namely, ascorbic acid, nitrite and nitrate, or phosphates. This study aimed to evaluate the effectiveness of four clean label alternatives as replacements for conventional chemical preservatives. These preservatives include cultured dextrose, phenolic compounds obtained from Olea europaea by-products, grape extracts, and vinagre derivatives. Each preservative has different properties, and the focus of this research was to determine which one(s) has a greater activity against pathogenic bacteria such as Clostridium sporogenes (DSM 767, NCA 3679). and a cocktail of Listeria monocytogenes (2542, FSL J1-177, FSL J1-031, FSL N3-013, FSL R2-499, FSL N1-227 and MF4077), while also preserving the product during its shelf life. This study involves the production of laboratory-scale meat analogues using the original industry formulation and formulations with each clean label preservative, followed by inoculation with pathogenic bacteria. The evolution of the pathogens was monitored, and the shelf life of the products was evaluated according to ISO standards. The results show positive prospects for clean label alternatives to replace current preservatives with healthier alternatives, in particular grape extracts and cultured dextrose, which have shown the best antimicrobial properties when added to meat analogues. However, further studies need to be conducted to assess the safety of these preservatives and their impact on the technological properties of meat analogues.
- Evaluation of nitrite reduction on the microbial safety of cooked smoked pork chouriçoPublication . Nunes, Maria; Cruz, Inês; Noronha, Lúcia; Komora, Norton; Pereira, Rui; Barbosa, Joana; Carvalho, Fátima; Teixeira, PaulaAim: Nitrite is a preservative used worldwide, particularly in the meat industry, to guarantee certain organoleptic and microbiological properties of delicatessen meat products, acting as a hurdle to pathogenic bacteria and protecting against bacterial spoilage. Cooked smoked pork chouriço contains nitrite in its formulation, which raises some concerns regarding the consumer’s health, and therefore the European legislation on the use of nitrites has been modified, where the maximum limit of 150 mg/kg of meat has been reduced to 80 mg/ kg of meat in the EU. The present study focuses on the assessment of the impact of nitrite reduction on the microbiological safety and organoleptic properties of pork chouriço. Method: The determination of total viable counts, lactic acid bacteria, Enterobacteriaceae, Escherichia coli and pathogenic bacteria (Listeria monocytogenes, Salmonella and spores of sulfito-reducing Clostridium) was performed according to ISO standards in pork chouriço produced with different nitrite concentrations. Organoleptic characteristics, such as colour, aw, pH and texture were evaluated at times 0 days, 30 days and 60 days of storage under vacuum at room temperature. Results: Although the nitrite concentration has been reduced to almost half of the usual concentration, the microbiological results show that that the product remains stable in 60 days of vacuum storage at room temperature and complies with the legal limits, below 1.0E+05 CFU/g for total viable counts and lactic acid bacteria. Regarding organoleptic properties, due to the heterogeneity of the product, the results show some high standard deviation, especially in colour and texture, but both aw and pH are in lign with the standard values obtained in the products. Conclusion: In conclusion, although further tests are needed to establish safety, no significant differences were observed in microbial growth during the product’s shelf-life, or in its organoleptic properties. Therefore, there is no evidence of safety problems associated with the consumption of smoked cooked pork chouriço with a decrease of more than 45% in the nitrite concentration. However, caution should be taken until further research confirms its safety.
- High hydrostatic pressure and pediocin PA-1 as a synergistic system to listeria monocytogenes inactivation in fermented meat sausagePublication . Maciel, Cláudia; Komora, Norton; Ferreira, Vânia; Saraiva, Jorge; Castro, Sónia Marília; Teixeira, Paula
- High hydrostatic pressure effects on Listeria monocytogenes and L. innocua: evidence for variability in inactivation behaviour and in resistance to pediocin bacHA-6111-2Publication . Bruschi, Carolina; Komora, Norton; Castro, Sónia Marília; Saraiva, Jorge; Ferreira, Vânia Borges; Teixeira, PaulaThe effect of high hydrostatic pressure (HHP) on the survival of 14 strains of Listeria monocytogenes from food or clinical origins, selected to represent different pheno and genotypes, was evaluated. Stationary phase cells were submitted to 300, 400 and 500 MPa at 10 °C, for 5 min. A high variability in the resistance of L. monocytogenes to pressure was observed, and particularly two strains isolated from food were significantly more baroresistant than the rest. Strains of L. monocytogenes resistant to one or more antibiotics exhibited significantly higher levels of survival after the high pressure treatment at 400 MPa. No correlation was found between strains' origin or thermal tolerance and resistance to HHP. The suitability of two strains of L. innocua as surrogates of L. monocytogenes, was also investigated. These exhibited significantly higher sensitivities to HHP than observed for some L. monocytogenes. The antimicrobial effect of the antilisterial bacteriocin (bacHA-6111-2) increased after L. monocytogenes cells had been exposed to pressure. The data obtained underlines the importance of strain selection for studies aiming to evaluate HHP efficacy to ensure safety of HHP-treated foods.
- High-pressure processing and lytic bacteriophage cocktail phageguard S as a synergistic hurdle system towards salmonella inactivation in egg whitePublication . Maciel, Cláudia; Campos, Ana; Komora, Norton; Pinto, Carlos A.; Brandão, Teresa R. S.; Saraiva, Jorge A.; Teixeira, PaulaSalmonella spp. still represents a major public health concern as the etiological agent of foodborne diarrhoeal illnesses. Salmonella Enteritidis is the most common serovar associated with non-typhoidal salmonellosis in the United States and Europe, through the ingestion of raw, undercooked eggs or egg-derived food products. The consumption pattern has changed worldwide, towards a growing demand for minimally processed foods. The association of emerging technologies with conventional antimicrobial agents has been scarcely exploited as a feasible multi-hurdle decontamination approach. The purpose of the present work was to develop a novel non-thermal technology through the combination of mild high pressure processing (HPP, 300 MPa) with the bacteriophage PhageGuard S towards a 4-strain Salmonella cocktail inactivation in egg white. A preliminary set of experiments allowed to establish the most adequate parameters to be employed in the proposed system. Concerning the HPP (200 to 600 MPa) resistance pattern of thirteen food and clinical Salmonella strains belonging to serovars Enteritidis, Typhimurium and Senftenberg, a prominent intrastrain heterogeneity was observed and as expected, higher pressure magnitudes elicited a lower survivability. Regarding the impact of the pressure processing on the egg white viscoelastic profile, it was found that from 400 MPa onwards the complex viscosity and elastic modulus increased noticeably. The second part of the work sought to investigate the decontamination potential of the proposed treatment. In the challenge assays performed in egg white comprising a high bacterial load (107 CFU mL-1), HPP per se was not able to accomplish a prominent bactericidal effect, whilst the combination with the bacteriophage elicited Salmonella inactivation to values below the detection limit. The association of the two hurdles was determined to be a synergism. Moreover, a scarce impact on the physical features of egg white – color, foaming capacity and rheological properties - was observed throughout the 7-day refrigerated storage (4ºC). To our knowledge, this is the first study documenting a sustainable non-thermal technology as a suitable alternative to egg white pasteurization since the synergistic system HPP-PhageGuard S accomplished a Salmonella 5- log reduction.
- Impact of nitrite reduction on the microbiological safety of cooked pork hamPublication . Nunes, Maria J. M.; Noronha, Lúcia; Cruz, Inês; Komora, Norton; Pereira, Rui; Barbosa, Joana; Carvalho, Fátima; Teixeira, Paula
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