Browsing by Author "Gibbs, Paul Anthony"
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- Campylobacter spp. as a foodborne pathogen: a reviewPublication . Silva, Joana; Leite, Daniela; Fernandes, Mariana; Mena, Cristina; Gibbs, Paul Anthony; Teixeira, PaulaCampylobacter is well recognized as the leading cause of bacterial foodborne diarrheal disease worldwide. Symptoms can range from mild to serious infections of the children and the elderly and permanent neurological symptoms. The organism is a cytochrome oxidase positive, microaerophilic, curved Gram-negative rod exhibiting corkscrew motility and is carried in the intestine of many wild and domestic animals, particularly avian species including poultry. Intestinal colonization results in healthy animals as carriers. In contrast with the most recent published reviews that cover specific aspects of Campylobacter/campylobacteriosis, this broad review aims at elucidating and discussing the (i) genus Campylobacter, growth and survival characteristics; (ii) detection, isolation and confirmation of Campylobacter; (iii) campylobacteriosis and presence of virulence factors; and (iv) colonization of poultry and control strategies.
- Contributing data for risk assessment of traditional fermented sausages: "Salpicão de Vinhais" and "Chouriça de Vinhais"Publication . Campelos, Maria Isabel; Silva, Joana; Gibbs, Paul Anthony; Teixeira, Paula“Salpicão de Vinhais” and “Chouriça de Vinhais” are traditional dry-fermented smoked meat sausages produced in Vinhais, a small region of Trás-os-Montes, Portugal. The scientific knowledge of this sausage variety is limited. Seventy-seven samples of “Salpicão” and “Chouriça de Vinhais” were purchased from producers, local markets and retail stores. Their microbiological and physical chemical characteristics were analysed. The same analyses were performed on the raw materials and ingredients and products during the production processes. Regarding the pathogenic flora, Staphylococcus aureus, spores of sulphite reducing clostridia, Escherichia coli 0157:H7, Yersinia spp. and Salmonella spp. were not detected in any of the samples analysed; Listeria monocytogenes was detected in 14.3% of the samples. The manufacturing process, namely fermentation, ripening/drying and smoking reduced the numbers of pathogen and hygiene indicator micro-organisms.
- Microbiological characterization of randomly selected Portuguese raw milk cheeses with reference to food safetyPublication . Almeida, Gonçalo; Figueiredo, Alexandre; Rôla, Marta; Barros, Rui Manuel; Gibbs, Paul Anthony; Hogg, Tim; Teixeira, PaulaSeventy raw milk cheeses made in different regions of Portugal, both hard and soft varieties, made with cow’s, ewe’s, or goat’s milk or combinations of these, were sampled within their quoted shelf lives for microbiological safety. On the basis of the presence or numbers of Escherichia coli, E. coli O157, Staphylococcus aureus, Salmonella, and Listeria monocytogenes, cheeses were categorized as satisfactory, acceptable, unsatisfactory, or unacceptable and potentially hazardous. Twenty-two of the 70 cheeses were classified as satisfactory or acceptable. Thirty-seven of the cheeses were considered unsatisfactory because of the presence of E. coli, S. aureus, or both, while 11 of the cheeses were graded as unacceptable and potentially hazardous because of the presence of excessive numbers of S. aureus, E. coli, or L. monocytogenes and the presence of Salmonella in three of these. All cheeses graded as unacceptable and potentially hazardous were soft or semisoft cheeses made with ewe’s and goat’s milk, with the exception of two hard cheeses made with cow’s milk. E. coli O157 was not detected in any of the cheeses. According to the present results, it seems that the presence or counts of pathogenic or indicator organisms in raw milk cheeses cannot be related to the processing conditions, milk type, or region of production
- Survival characteristics of pathogens inoculated into bottled mineral waterPublication . Ramalho, Rita; Afonso, Anita; Cunha, Joaquim; Teixeira, Paula; Gibbs, Paul AnthonyTo assess the risk of contracting a waterborne disease from mineral water and to implement control systems in the mineral water industry, knowledge of the factors affecting the survival and multiplication of non-indigenous bacteria is needed. The survival of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica inoculated into a Portuguese bottled mineral water was investigated under different conditions: light and dark, different recovery media, presence or absence of autochthonous flora and different ages of water, based on their culturability. For all the pathogenic bacteria higher survival was obtained under dark conditions of storage and when enumeration was performed on non-selective media. Survival of E. coli, Y. enterocolitica and S. typhimurium was longer in fresh water than in old water; results obtained with S. aureus were not conclusive. Survival of E. coli, Y. enterocolitica and S. typhimurium was lower in non-sterile mineral water while the survival of S. aureus was lower in sterilized mineral water.