Dynamics of the yeast flora in artisanal country style and industrial dry cured sausage (yeast in fermented sausage)

Yeast can act as an adjunct in the sausage-making process as a way to prevent or reduce excessive acidification during aging of products. Two kinds of process were studied: industrial and artisanal country style. Three hundred and fifty three yeast strains were isolated, characterized and identified by biochemical and molecular techniques. Evolution of pH, Aw, weight loss, bacterial growth and proteolytic and lipolytic activity was studied. Final pH in artisanal country style product was higher than in the industrial sausage. There was little difference noted between final weights of products but it was observed a lower yeast count in artisanal country style sausage. No relevant difference was observed in center or surface yeast count in both products. The biochemical assay identified six yeast genera and the molecular test confirmed four different genera, and further analysis showed predominance of the genera Debaryomyces. The relations between this four genera and isolation point (center or surface of sausage) were established. The presence of yeast in the center/surface of ART sausage was more prevalent than in the same places of industrial sausage.     

Effect of inoculation of selected Staphylococcus xylosus and Lactobacillus plantarum strains on biochemical,microbiological and textural characteristics of a Tunisian dry fermented sausage

In this study, a selected starter culture of Lactobacillus plantarum and Staphylococcus xylosus was used for the manufacture of a traditional Tunisian dry fermented sausage. Changes of microbiological, biochemical, sensorial and textural characteristics during the ripening of sausages were investigated.Counts of lactic acid bacteria and staphylococci were significantly higher in inoculated sausages than in control ones. Moreover, the acidifying activity of the selective L. plantarum strains improved the hygienic quality of fermented sausages by reducing counts of Enterobacteriaceae. Both a significant decrease in pH and a significant increase in nitrite contents were observed in inoculated sausages compared to control ones. The loss of moisture during the ripening of sausages was not affected by the use of starters. Proteolysis and lipolysis were observed both in control and in inoculated sausages; however, these activities during ripening could be due to the activity of starter culture enzymes or the activity of meat endogenous enzymes. The Factorial Discriminative Analyze (FDA) of sensorial parameters (aroma, color, taste and firmness) discriminate clearly inoculated sausages from non-inoculated ones. In fact, inoculated sausages showed a more intensive red color, related to the production of nitrosomyoglobin pigment, and an acid flavor. Finally, textural parameters of sausages were not affected by the use of the selective starters.     

Biogenic amine content and aromatic profile of Salama da sugo,a typical cooked fermented sausage produced in Emilia Romagna Region (Italy)

Salama da sugo is a fermented sausage from Ferrara tradition, subjected to a long ripening period (4–6 months). It can be consumed after cooking, served with its sugo, i.e. the liquid extracted by cooking process. Besides to pork meat and fat, also NaCl, curing salts, sugar, spices and almost 15% of red wine are added. The aim of this research was the microbial and aromatic profile characterization of Salama da sugo during ripening. The product was sampled in order to study chemico-physical parameters, microbial population composition (Enterobacteriaceae, lactobacilli, enterococci, micrococci and staphylococci, including coagulase positive, fungi, total mesophilic bacteria), biogenic amine content and aromatic profile. The results showed that this traditional product was characterized by a complex aroma.Moreover, the biogenic amine concentration was low (less than 200 mg/kg for tyramine, about 50 mg/kg for cadaverine and putrescine while histamine was below the detection limit).     

Effect of starter cultures on microbial ecosystem and biogenic amines in fermented sausage

The microbial ecology of fermented sausages inoculated with different starter cultures (Pediococcus pentosaceus + Staphylococcus xylosus, batch A; Lactobacillus farciminis + Staphylococcus saprophyticus, batch B) was studied by culture-dependent and independent methods. The concentration of biogenic amines, pH and a_w (water activity) were followed. The starter B can inhibit indigenous bacteria effectively judged by traditional microbiological method and PCR-DGGE fingerprint. There was no statistical difference in pH between batches A and B at 2 days when substantial amounts of BAs were produced, while the amounts of histamine, putrescine, cadaverine and tyramine in batch B was lower than in batch A significantly (P < 0.001). As a result, the starter cultures which can complete, grow well and inhibit amine-positive bacteria play an important role in reducing the production of BAs during ripening of fermented sausage.     

Biogenic amines content in traditional dry fermented sausage Petrovská klobása as possible indicator of good manufacturing practice

The aim of this study was to determine the content of nine biogenic amines (tryptamine, phenylethylamine, putrescine, cadaverine, histamine, serotonin, tyramin, spermidine and spermine) and total biogenic amines in traditional dry fermented sausage Petrovská klobása at the end of drying period, as possible indicators of good manufacturing practice (GMP).Chromatographic separation of dansyl chloride derivatizated amines was completed in 8 min. Analyses were performed by HPLC-DAD on Eclipse XDB-C18 column. Tryptamine and spermine were determined in all analyzed samples, while histamine, serotonin and spermidine were not detected in any samples. Average content of individual biogenic amine ranged from 5.54 mg/kg (putrescin) to 75.1 mg/kg (tryptamine) and total content of biogenic amines varied from 77.8 mg/kg to 174 mg/kg.The results obtained in this study provided no evidence for deviations from good manufacturing practice in Petrovská klobása production.     

Survival of Enterobacteriaceae during processing of Chorizo de cebolla,a Spanish fermented sausage

Chorizo de cebolla is a popular semi-dry fermented sausage from Galicia (NW of Spain). The survival of Enterobacteriaceae was investigated in three batches of C. de cebolla (one of them hand made and the other two manufactured industrially). The maximum count of Enterobacteriaceae was obtained in each lot after 2 days of the raw sausage mix being stuffed and from then on it started to decrease until it disappeared in the fourth week of ripening in one of the batches manufactured industrially and after 6 weeks in the other. In the artisanal sausages the counts practically decreased exponentially until the third week of ripening, increasing in the following week before again decreasing until the end of ripening, though they never disappeared. Escherichia coli, Serratia odorifera and Enterobacter intermedius were the only species isolated during the curing process of the hand made sausages, E. coli being the dominant species. In the industrial ones a higher number of species were isolated, with the predominance of E. coli and Hafnia alvei.     

Presence of Listeria monocytogenes in Turkish style fermented sausage (sucuk)

Turkish style fermented sausage (sucuk) is a well-known and very popular meat product produced in Turkey. The growth of Listeria monocytogenes in fermented sausage and other meat products may cause serious health problems for consumers. The aim of this study is to assess the presence of L. monocytogenes in sucuk sold in Istanbul. During the period of February 2004–January 2005, a total of 300 sucuk samples were obtained from various markets located in Istanbul and the presence of L. monocytogenes was analyzed according to “Food and Drug Administration” (FDA) method. The results were found to be positive for Listeria spp. and L. monocytogenes as 63 (21%) and 35 (11.6%) respectively.     

Survey of prevalence and seasonal variability of Listeria monocytogenes in raw cow milk from Northern Italy

Listeria monocytogenes is an important food-borne pathogen causing meningitis, meningo-encephalitis and abortion. Both sporadic and epidemic human listeriosis cases are associated with the consumption of contaminated foods. To assess the potential risk to consumer health, the presence of L. monocytogenes was investigated using qualitative and quantitative methods in raw milk (bulk tank milk and milk for vending machine) collected from 2010 to 2013 in Northern Italy (Lombardy and Emilia-Romagna regions). Overall, L. monocytogenes was detected in 145 on 8716 of raw milk samples, with a prevalence of 1.66% (95% C.I. 1.4%–1.7%). The prevalence ranged from 0.52% (95% C.I. 0.3%–0.9%) in 2012 to 2.7% (95% C.I. 2.0%–3.8%) in 2013, but no trend of increase was observed in four-years of investigation. The pathogen was detected from 2.2% (95% C.I. 1.9%–2.6%) of bulk tank milk and from 0.5% (95% C.I. 0.3%–0.8%) of milk for vending machine. A significative difference (p < 0.05) of the prevalence data was observed between data collected in two different regions of Northern Italy with an higher prevalence in Lombardy. In addition to the geographical area, the L. monocytogenes presence was influenced also by the seasonal period of collection samples, with peaks in spring and autumn. These results confirm the raw milk can be a source of foodborne illness outbreaks if consumed without sanitizing treatments, but the low prevalence and the low contamination levels (more than 80% of the contaminated samples contained <10 cfu ml^−l of L. monocytogenes) proving the hygienic quality of the milk produced in Northern Italy.     

Effect of rose polyphenols on oxidation,biogenic amines and microbial diversity in naturally dry fermented sausages

Rose polyphenols (RPs) have antioxidant and antibacterial activities. In order to evaluated the application of RPs in meat products, the effect of RPs on the safety of fermented sausages was investigated. In the present study, RPs inhibited the increase of pH. Phenylethylamine, putrescine, cadaverine, tyramine and spermidine can be detected in sausages, while spermine and tryptamine were not observed. Sausages containing RPs had lower thiobarbituric acid reactive substance values and biogenic amines than the control. Moreover, RPs decreased the total bacterial count but increased growth rate of lactic acid bacteria. The effect of RPs on oxidation, biogenic amines and bacterial growth is dependent on the concentration. High-throughput DNA sequence analysis revealed that operational taxonomical units (OTUs) of samples without PRs were higher than those containing 3 mg/g RPs, and 323 OTUs shared between two batches. Especially, a higher level of Lactobacillales OTUs was observed in the 3 mg/g batches. These results indicated that RPs could be used to improve the safety of fermented sausage by inhibiting lipid oxidation, biogenic amines formation and spoilage bacterial growth, and increasing growth rate and richness of lactic acid bacteria.     

Purification and partial characterization of M1-UVs300, a novel bacteriocin produced by Lactobacillus plantarum isolated from fermented sausage

A novel bacteriocin-M1-UVs300, which was produced by Lactobacillus plantarum M1-UVs300, was purified and characterized. Bacteriocin-M1-UVs300 was purified sequentially by an aqueous two-phase system (ATPS) and a Sephadex G-50 gel chromatography assay, combined with reverse phase high-performance liquid chromatography (RE-HPLC). The purification resulted in a 3221.63 IU ml⁻¹ titer with a 20.41- fold purification of the original activity. According to a Tricine-SDS-PAGE analysis, the molecular weight of the bacteriocin-M1-UVs300 was approximately 3.4 kDa. A quantitative analysis of the secondary structure of bacteriocin-M1-UVs300 results showed that it had a major β-sheet content of 52.43%, α-helix of 16.17%, β-turn of 15.27%, and a random coil of 16.12%. A partial sequence, GAKSKYGNVG-, was obtained by N-terminal amino acid sequence analysis. The antimicrobial spectrum of bacteriocin-M1-UVs300 exhibited activity against Gram-positive bacteria and Gram-negative bacteria. In addition, it was relatively heat-resistant, active over a range of pH 2–8, and sensitive to proteolytic enzymes, but it was not sensitive to α-amylase. The additives significantly increased the activity of bacteriocin-M1-UVs300 significantly. These findings indicated that bacteriocin-M1-UVs300, is a novel bacteriocin with a broad inhibitory spectrum, and that it had the potential to act as a natural preservative in the food industry.     

Behaviour of food-borne pathogens on dry cured sausage manufactured with herbs and spices essential oils and their sensorial acceptability

Dry cured sausages such as Portuguese chouriço de vinho are made generally with roughly minced pork and fat and seasoned with a large variety of herbs and spices. It is a particular sausage because meat is marinated in wine with other seasonings during 24–48 h before stuffing. Nowadays, health concerns of consumers have left food processors with less flexibility to choose preservative substances and methods. Thus, the objective of this study was to assess the antimicrobial effect of essential oils (EOs) of herbs and spices traditionally used in seasoning dry cured sausage chouriço against Salmonella spp., Listeria monocytogenes and Staphylococcus aureus. First, antibacterial activity of 14 EOs was screened by disk diffusion assay. Those EOs that displayed antimicrobial activity were further characterized by GC–MS and added as natural antimicrobial substances to the manufacture of chouriço at two concentrations (0.005% and 0.05%). Samples were analyzed 24 h after the preparation of the batter and after 3, 8, 15 and 21 days.After 15 days of drying, Salmonella spp. and L. monocytogenes counts decreased by ca. 2 log cfu/g in all samples. At 3 days, Salmonella spp. was already undetectable in chouriço made with 0.05% of garlic and oregano EOs. Both Salmonella spp. and L. monocytogenes were not detected after 8 and 15 days of drying respectively. S. aureus was still presented after 21 days of drying although its counts were not high enough to a potential enterotoxins presence. Utilization of EOs in manufacture of dry cured sausage resulted in an interesting strategy to improve its safety against Salmonella spp, L. monocytogenes and S. aureus, but with sensory limitations, that does not allow its use in high concentrations, that are those more interesting for pathogen inhibition.However, results with good potential to be applied by the industry were found, once the level of addition of 0.005% contributed for significant reductions on the pathogen's counts and for a shorter period to achieve the not detectable level, allowing the industry to shorten the drying period and, thereafter increasing yield production.     

Anti-listeria activity of Pediococcus pentosaceus BCC 3772 and application as starter culture for Nham, a traditional fermented pork sausage

Lactic acid bacteria forming bacteriocin active against Listeria monocytogenes were screened for potential use in controlling growth of L. monocytogenes in Nham, a Thai traditional fermented pork sausage. Based on the spot-on-lawn assay, Pediococcus pentosaceus BCC 3772 was found to produce the highest anti-listeria activity. Through a series of chromatographic techniques, Edman N-terminal sequencing and mass spectrometry, this anti-listeria compound showed a complete homology to pediocin PA-1/AcH. Inoculation of P. pentosaceus BCC 3772 in Nham caused a significant decrease of 3.2 log in population of spiked L. monocytogenes within 18-24 h of fermentation, in comparison with the initial count with no significant changes in sensory properties and consumer acceptability on the overall characteristics of the final fermented Nham products. These results indicate that the P. pentosaceus BCC 3772 should be useful as a functional starter culture for control of L. monocytogenes without compromising the unique quality of Nham.     

Aflatoxins occurrence in milk and feed in Northern Italy during 2004–2005

Aflatoxin B₁, a common occurring type of aflatoxin in feed, is a potent cancer-causing agent. Lactating cows fed with aflatoxin-contaminated feed trasmit the toxin, as the metabolic form aflatoxin M₁, into the milk with high risk for consumers. The aim of this study is to determine the contamination degree of raw milk and feed in Valle d’Aosta region.From the beginning of 2004 to the end of 2005 samples of raw cow’s milk and cattle feed has been analysed: in 2004, the presence of aflatoxin M1 in milk and B1 in feed was higher than the maximum allowable in 1.7% of raw milk samples and in 8.1% of feed samples. In 2005 the presence of these aflatoxins are below the limits of EU regulations.The samples were analysed with an ELISA immunoassay, used as screening test, and the positive samples were confirmed by the HPLC analysis.     

Survey of aflatoxins and ochratoxin a contamination in food products imported in Italy

In this study the levels of aflatoxins (AF B₁, B₂, G₁ and G₂) and ochratoxin A (OTA) were monitored in several food products imported in Italy with a high contamination risk. A total of 345 samples were collected from the Maritime Authority of Salerno Customs Port during the period from January 2008 to December 2009 and analyzed by immunoaffinity chromatography as clean-up, high performance liquid chromatography with fluorescence detection for quantification and tandem mass spectrometry for confirmation. The analytical methods were validated on different food matrices and meet the performance criteria set by EC Regulation No. 401/2006 for mycotoxin analysis. The results obtained in this survey showed that 7% of the total samples contained detectable levels of AFs and OTA, and 1.2% had AFs concentrations exceeding the maximum limits set by EU regulation. OTA was the most prevalent mycotoxin, with an incidence of 17.6% of samples analyzed for OTA. The highest detected levels were 23.70 μg kg^?1 of OTA in a green coffee sample and 70.69 μg kg^?1 of AFs in an apricot kernels sample. Among the food products analyzed, hazelnuts paste and dried vine fruits were the commodities mainly contaminated with AFs and OTA, respectively.     

Regional monitoring plan regarding the presence of aflatoxin M1 in pasteurized and UHT milk in Italy

The aim of the study involved evaluation of the presence of aflatoxin M₁ in milk for sale in a specific North West Italian region, Piedmont. The study, conducted from November 2003 to July 2005, was linked to the specific emergency situation which arose due to the climatic conditions during the summer of 2003 which encouraged the development of aflatoxin B₁ in items used for animal feed. This in turn led to the transfer of the metabolite, aflatoxin M₁, into the milk. In total some 316 milk samples were collected during the commercial phase by the official control bodies and analysed. The analysis involved the use of high pressure liquid chromatography (HPLC) combined with fluorimetric measurement, and purification of the extracts using immunoaffinity columns. The results indicated only 2 non conforming samples (0.6%), with limits higher than those set out in the regulations (0.05 μg L⁻¹). In addition, the analyses revealed, in 5 samples (1.6%), threshold values of 0.05 μg L⁻¹. From the data obtained it can be seen that the “aflatoxins” problem only marginally affected Piedmont Region though the trend for average monthly values suggests a return to the use of contaminated animal feed as soon as official controls are less intensive.     

Influence of environmental conditions and building structure on food quality: A survey of hand-crafted dairies in Northern Italy

The present study investigated several small dairies, located in mountain areas of Northern Italy, with the aim to identify critical factors that are frequently neglected despite their potentially decisive role in improving hygiene standards of dairy processing and work safety. The results highlighted the structural and procedural aspects involved in sanitary requirements of traditional dairy production.Our analysis has made it clear that processing environment is often inadequately protected from external contamination, and design and realisation of buildings is not suitable for food processing requirements. For example, the main critical points for food safety in relation to building structure are indoor layout of a dairy, and coating materials for floors and walls that, although smooth and washable, do not withstand chemical attack, environmental conditions, and mechanical stress. From a procedural point of view, cleaning operations are not carried out thoroughly, and working practices are hygienically deficient.     

中国天然气产业链“十二五”整体规划透视

中国近期陆续发布了由天然气产业链“十二五”系列规划构成的产业链整体规划,整个产业链“十二五”期间的发展蓝图已清晰可见。整体规划的背景主要基于：需要应对国内外减排双重压力、国内经济发展水平迈上新台阶、产业链可持续发展面临一系列挑战等。整体规划的亮点体现在：①天然气总规划供应能力对规划消费量有保障,从资源量到消费量逐级留有余地,增加供气保障能力,非常规天然气资源开发和开发能力储备为“十二五”以后建立资源保障序列;②以天然气基础设施为重点,扩大用气地区,增加对用气区的输气能力,以多种手段拓展天然气利用,强化产业链各环节的有效衔接;③开展多种形式的探索,推动产业链向竞争性结构演变。整体规划尚有的缺失为：①能源管理体制难以适应发展的需要,整体规划受到分割,关键制度的变迁没有时间表和路线图,顶层制度设计不够;②天然气产业链结构发展目标不明,对未来走向判断困难,如对生产商的上、中、下游一体化如何规范等没有明确意见。     

Managerial attitudes, acceptance and efficiency of HACCP systems in Hungarian catering

The Hungarian catering industry has to face up to numerous challenges nowadays because of rising costs and stagnating purchasing power. Under these conditions the managerial acceptance of the compulsory introduction of the HACCP system is rather mixed. This research is based on a direct question survey, with the aim of analysing the relation amongst the strategies of catering service managers, their attitudes towards food hygiene and the HACCP system, their managerial experiences about working with the HACCP system, as well as the evaluation of hygienic practice of catering service providers by independent specialists. More than 1100 questionnaires were processed. Two main approaches were analysed with regard to the general attitudes of catering managers: the hygiene and the cost-oriented approaches. The acceptance of HACCP systems lacked homogeneity to a significant extent. 28% of the respondents considered that the increasing quality and safety were the really important and necessary tasks. 41% of the respondents had a rather reluctant attitude towards their systems, mainly as a consequence of fear of extra investment and administrative burdens. Last but not least, the third group of managers accepted the importance of hygiene, but did not acknowledge the possibilities offered by HACCP for better work-organisation and clearer determination of responsibility. The structural equation analysis between the managerial strategy and attitudes, as well as the hygienic conditions, have proven numerous significant relations between these factors, but the results highlight the importance of efforts aiming at better integration of the HACCP approach in managerial activities. There is a real danger that this system will be simplified to accomplish administrative tasks.     

Packaging and irradiation effect on lipid oxidation,color, residual nitrite content,and nitrosamine formation in cooked pork sausage

The packaging and irradiation effect on physicochemical changes in pork sausage was studied. Emulsion-type cooked pork sausage was made with (156 ppm) or without NaNO₂ and packaged in aerobic, vacuum, and CO₂ (100%) conditions. The samples were irradiated at 0 and 5 kGy absorbed dose, and lipid oxidation, color, content of residual nitrite and volatile N-nitrosamines were analyzed during storage at 4 °C. The NaNO₂ addition to sausage significantly reduced lipid oxidation and increased Hunter color a-value. Residual nitrite content was the lowest in the sausage with CO₂ packaging, but no irradiation effect was found at 5 kGy. Irradiation at 5 kGy reduced the content of nitrosodimethylamine at 0 week and nitrosopyrrolidine at 4 week. Results indicated that CO₂ packaging is better in terms of lower residual nitrite content in the sausage. In addition, irradiation may minimize the risk of exposure to carcinogenic volatile N-nitrosamines possibly present in cooked pork sausage.     

Occurrence of ochratoxin A before bottling in DOC and DOCG wines produced in Piedmont (Northern Italy)

Italy is one of the countries where ochratoxin A (OTA) contamination in wine poses more risks. Previous surveys on the occurrence of OTA have poorly considered north Italian wines. In this study, 1206 red and white DOC and DOCG wines produced in Piedmont (Northern Italy) from 2000 to 2007 have been analyzed for OTA level (0.116 μg l⁻¹) and incidence (68.0%). The monitoring – the widest per number of Italian wine samples considered – analyzed the OTA contamination of wines in tanks just before bottling. OTA level and incidence were significantly higher in red (0.121 μg l⁻¹, 69.4%) than in white (0.086 μg l⁻¹, 61.3%) wines. Among the white wines, the incidence was significantly lower in the Moscato wines (7.3%), due to the different wine processing. The differences in the mean OTA level in the three main grapevine varieties of red wines could be related to the harvest period. Among the Nebbiolo appellations, a reduction of the OTA level was noticed with increasing the wood aging period. A significant effect of the vintage year was also registered.