Effect of packaging technology on microbiological and sensory quality of a cooked blood sausage, Morcela de Arroz, from Monchique region of Portugal.

Morcela de Arroz (MA), a popular Portuguese blood sausage, with high pH and water activity (aw), is traditionally commercialized without preservatives and unpacked. This study evaluated the best packaging solution to extend MA shelf life stored at 4±1°C for 44days: without packaging (WP), vacuum (VP) and modified atmosphere packaging (MAP) (80% CO2; 20% N2). Mesophilic (MTVC), psychrotrophic (PTVC), lactic acid bacteria (LAB), pseudomonads, molds and yeasts, Enterobacteriaceae, Listeria monocytogenes, Salmonella spp., Bacillus cereus, Clostridium perfringens, sensory properties, pH, moisture and aw were studied. Moisture and aw decreased (p<0.05) in WP. pH decreased in WP and MAP during storage. MTVC and PTVC counts increased to values around 7logCFU/g at 44days of storage. LAB and Enterobacteriaceae counts were higher (p<0.05) in VP. Pseudomonads were inhibited (p<0.05) by MAP after 8days of storage. Sensory parameters were affected (p<0.05) by packaging and storage time. Globally, MAP performed better.

Behavior of Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus in Chouriço de Vinho, a dry fermented sausage made from wine-marinated meat.

Portuguese chouriço de vinho is made by drying coarsely minced meat and fat that has been previously marinated with wine (usually red), salt, and garlic for 1 to 2 days at a low temperature (4 to 8 °C). This procedure may improve the microbiological safety of the product. The aim of this study was to evaluate the behavior of three pathogens in this product, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus, to establish the minimum period of drying and maturation necessary to render safe products. The pathogens were inoculated in the chouriço de vinho batter. A factorial design was used to study the following variables in the fermentation process: (i) the presence or absence of an indigenous Lactobacillus sakei starter culture; (ii) the presence or absence of fermentable carbohydrates; and (iii) the salt level (1.5 or 3%). The samples were analyzed 24 h after the preparation of the batter (at stuffing); after 7, 15, and 30 days of drying; and after 30 days of storage at 4 °C under vacuum. Under all of the conditions studied, the levels of the three pathogens decreased during the drying period. In the early stages of drying, the addition of L. sakei starter culture and/or carbohydrates resulted in lower levels of gram-positive pathogens. After 15 days of drying, populations of all pathogens decreased by ca. 2 log in all samples. At that sampling time, L. monocytogenes was undetectable in the chouriço de vinho with L. sakei starter culture and carbohydrates. The mean count of S. aureus after 15 days of drying was below 1 log CFU/g. After 30 days of drying, no pathogens were detected. The drying period could be shortened to 15 days when considering only the gram-positive pathogens studied and the use of a starter culture and carbohydrates. Due to the low infective dose of Salmonella spp., the product should be considered safe after 30 days, when this pathogen became undetectable.

Comparative survey of PAHs incidence in Portuguese traditional meat and blood sausages.

Sixteen polycyclic aromatic hydrocarbons (PAHs) in representative traditional sausages produced in "Trás-os-Montes" and "Alentejo", were determined. Light PAHs represented similar overall contents in both regions and showed close decreasing order patterns (ACY, PHE, FLR and NAP), irrespective of the product type considered. Amongst the carcinogenic/mutagenic PAHs analyzed (PAH8), both regions also had greater contents associated to BaA and CHR, with slightly higher values for the former compound in "Alentejo" and, oppositely, for the later in "Trás-os-Montes". However, their quantitative comparison showed that the general mean total PAH content found in "Trás-os-Montes" was almost 3-fold higher than in similar products from "Alentejo" and this factor was about 8-fold superior when the PAH8 and PAH4 indicators were compared, expressing benzo[a]pyrene toxic equivalencies (BaPE), 15 times (total mean toxicity), 34 times (PAH8) and 9 times (PAH4) higher. In general terms, the mean BaP content of all analyzed samples from "Alentejo" was 0.41 µg kg(-1). Differently that value in "Trás-os-Montes" reached 3.57 µg kg(-1), expressing concerning average contents of 5.35, 5.87 and 4.51 µg kg(-1) in Chouriço de Carne, Moura and Salpicão sausages, respectively.

A comparison of the physicochemical and sensory characteristics of alheira samples from different-sized producers.

Alheira is a traditional Portuguese meat product made from boiled meat, usually pork and/or poultry, and bread. The physicochemical and sensory properties of alheira were analyzed to determine the relationships between them and to evaluate how they are affected by the product's origin i.e. if is produced on a small or industrial scale. The most important variables used to characterize alheira are: color, visual evaluation of the amount of meat and bread, paprika aroma, clamminess and fibrousness, water activity, moisture, fat, carbohydrate content, hardness and color parameters (L(∗),a(∗), and b(∗)). Principal component analysis demonstrated that drying has a major effect on these characteristics, as it plays a part in the product's physical make-up. Using these parameters it was possible to ascertain that industrial products enjoyed higher levels of consumer acceptability, given that they contain a higher proportion of meat and undergo a shorter drying process.

Tracing Salmonella in Alheira processing plants.

AIMS: To investigate the sources of Salmonella spp. in Alheira and how to trace it, by studying the way that Salmonella spp. is distributed across production lines, by applying multifactorial correspondence analysis to occurrence data, and through the use of polymerase chain reaction (PCR) molecular typing methods. METHODS AND RESULTS: Four production lines, four batches of Alheira and 14 sampling sites were analysed over four sampling periods. Eighty-five Salmonella spp. isolates were obtained from the 896 microbial analyses performed. The basic occurrence analysis values, multiple correspondence analysis and PCR molecular typing methods confirmed that the presence of Salmonella spp. in Alheira was directly related to it being present in casings. Results obtained from PCR molecular typing added a measure of detail, highlighting potential cross-path contamination caused by contaminated surfaces. CONCLUSIONS: The presence of Salmonella spp. in Alheira was a result of the use of contaminated casings, as well as cross-path contamination caused by contaminated surfaces. An analysis of the occurrence data indicated that these casings were the source of Salmonella spp. contamination in Alheira. PCR molecular typing methodology, which is known to have a greater discriminatory power and tracing capacity, indicated the presence of cross-path contamination. SIGNIFICANCE AND IMPACT OF THIS STUDY: Increased awareness of Salmonella spp. contamination sources and their spread across the production line helps shape the development of new strategies for controlling this pathogen.

Multiple correspondence analysis and random amplified polymorphic DNA molecular typing to assess the sources of Staphylococcus aureus contamination in alheira production lines.

Sources and tracing of Staphylococcus aureus in alheira (garlic sausage) production were evaluated by multifactorial correspondence analysis (MCA) of occurrence data and a random amplified polymorphic DNA (RAPD) on S. aureus isolates. Samples from four production lines, four different production batches, and 14 different sampling sites (including raw material, different contact surfaces, and several stages of alheira manufacturing) were analyzed at four sampling times. From the 896 microbial analyses completed, a collection of 170 S. aureus isolates was obtained. Although analysis of the occurrence data alone was not elucidative enough, MCA and RAPD-PCR were able to assess the sources of contamination and to trace the spread of this microorganism along the production lines. MCA results indicated that the presence of S. aureus in alheira was related to its presence in the intermediate manufacturing stages after heat treatment but before stuffing in the casings. It was also possible to associate a cross-contamination path related to handler procedures. RAPD-PCR typing in accordance to MCA results confirmed the cross-contamination path between the raw material and casings and the role of handlers as an important cross-contamination vehicle.

Traditional dry fermented sausages produced in small-scale processing units in Mediterranean countries and Slovakia. 1: Microbial ecosystems of processing environments.

Microbial ecosystems were surveyed in 314 environmental samples from 54 Southern and Eastern European small-scale processing units (PUs) manufacturing traditional dry fermented sausages. The residual microflora contaminating the surfaces and the equipment were analysed after cleaning and disinfection procedures. All the PU environments were colonised at various levels by spoilage and technological microflora with excessive contamination levels in some of the PUs. Sporadic contamination by pathogenic microflora was recorded. Salmonella and Listeria monocytogenes were detected in 4.8% and 6.7% of the samples, respectively, and Staphylococcus aureus was enumerated in 6.1% of the samples. Several critical points were identified, such as the machines for S. aureus and the tables and the knives for L. monocytogenes; this knowledge is crucial for the improvement of hygiene control systems in small and traditional meat processing industries. The variability of the residual contamination emphasized the different cleaning, disinfecting and manufacturing practices routinely followed by these small-scale processing units.

Influence of ultimate pH on bovine meat tenderness during ageing.

The aim of this work was to evaluate the influence of ultimate pH and ageing at 2±2°C on the tenderness of beef. The m.longissimus thoracis et lumborum from 23 young bulls excised at 28 h post mortem were grouped into: Normal (pH 5.5 to 5.8) moderate DFD (mod DFD) (5.80.05) differences in soluble collagen and myofibrillar protein solubility (MPS) at pH 5.5 were found between the pH groups at any time. The tenderness evaluated by both methods was significantly (p<0.05) related to MFI, MPS at pH 7.0, cooking loss and juiciness. Total and soluble collagen, sarcomere length, intramuscular fat and MPS at pH 5.5 were not significantly (p>0.05) related with tenderness.