Percorrer por autor "Nunes, Fernando M."
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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.
- Time-dependent accumulation of biogenic amines and microbial succession during dry-aging of beef: safety implicationsPublication . Ribeiro, Ana J.; Milheiro, Juliana; Nunes, Fernando M.; Carvalho, Teresa B. de; Barbosa, Joana B.; Silva, Filipe; Teixeira, Paula; Saraiva, Cristina M.Dry-aging of beef under controlled temperature, humidity and airflow reshapes the surface microbiota and may influence biogenic amine (BA) accumulation. In this study, culture-based enumeration, 16 S rRNA gene profiling of combined crust + inner meat, and validated HPLC quantification of BAs were integrated to track safety- and quality-relevant changes over 60 days. Sequencing showed Pseudomonadota and Bacillota consistently >95 % of reads; communities were dominated by Pseudomonas, Brochothrix and Psychrobacter, with Acinetobacter rising at mid-aging. Alpha diversity peaked at day 35 (Shannon 1.33???2.12; overall P = 0.0225; day 35 vs day 1, adjusted P = 0.0069) and became heterogeneous by day 60. Culture confirmed a surface-led, aerobic succession: crust counts increased and Pseudomonas reached 5.6 log CFU/g at day 60, whereas inner-muscle counts declined across groups; pathogens were not detected. In the inner meat, cadaverine rose from non-detectable to 31 ± 37 mg/kg at day 60 P < 0.001), spermine peaked at day 35 (52 ± 14 mg/kg; P < 0.001), while histamine remained <5 mg/kg and other BAs showed no significant change. All inner-meat BAs remained below commonly cited concern ranges, though late-stage variance indicates sporadic hot spots, likely reflecting diffusion from the crust and proteolysis-enabled precursor supply. Integrating microbes and metabolites identified two ecological–metabolic tendencies linking psychrotrophic genera with polyamines or diamines. In practice, day 35 emerges as a quality “sweet spot,” whereas approaching day 60 warrants tighter surface management and targeted monitoring of pseudomonads, Enterobacteriaceae and cadaverine/putrescine.