Cluster familiare di infezione da Listeria monocytogenes

Listeria monocytogenes is a pathogen frequently found in dairy products. Its control in fresh cheeses is difficult, due to the psychrotrophic properties and salt tolerance. Bacteriocinogenic lactic acid bacteria (LAB) with proven in vitro antilisterial activity can be an innovative technological approach but their application needs to be evaluated by means of in situ tests. In this study, a novel bacteriocinogenic Lactococcus lactis strain ( Lc . lactis DF4Mi), isolated from raw goat milk, was tested for control of growth of L. monocytogenes in artificially contaminated fresh Minas type goat cheese during storage under refrigeration. A bacteriostatic effect was achieved, and counts after 10 days were 3 log lower than in control cheeses with no added LAB. However, this effect did not differ significantly from that obtained with a non-bacteriocinogenic Lc. lactis strain. Addition of nisin (12.5 mg/kg) caused a rapid decrease in the number of viable L. monocytogenes in the cheeses, suggesting that further studies with the purified bacteriocin DF4Mi may open new possibilities for this strain as biopreservative in dairy products.

Brucellosis is a worldwide zoonotic disease. Generally, humans can be infected by either the consumption of raw milk and fresh cheeses made from unpasteurised milk or by contact with infected animals, mainly in endemic regions. In this study, we investigated a brucellosis outbreak in State of Guanajuato, an endemic region of Mexico. Microbiological culture of human blood, raw milk from cows and goats, and fresh cheeses was performed to isolate Brucella. Identification of the bacteria was done by bacteriological procedures and by multiplex Bruce-ladder polymerase chain reaction (PCR). Brucella melitensis was isolated from patients, infected goats, and fresh goat cheeses; while Brucella abortus was isolated from cows. All patients had eaten fresh cheese, but no occupational exposure to animals was reported. The results of molecular typing did not show any Brucella vaccine strains. The isolation, identification, and molecular characterisation of Brucella spp. in both human brucellosis cases and infected animals are very important to identify the source of infection and to take control measures in endemic regions.

ABSTRACTProteolysis is specific for each type of cheese and might be affected by heat treatment. Studies have shown the ability of cheeses to produce bioactive peptides with antioxidant or anti-hypertension bioactivities, which have been related to ripening time or activity of starter cultures, however, little is known about their production in fresh cheeses. Our objective was to evaluate antioxidant and angiotensin-converting enzyme inhibitory (ACEI) activities in fresh goat cheeses elaborated without starters using pasteurized and raw milk from different seasons. Proteolysis was measured by acid-soluble nitrogen, non-protein nitrogen and ethanol-soluble nitrogen indexes, using the Kjeldahl method and reverse phase high performance liquid chromatography (RP-HPLC). Each fraction’s antioxidant and ACEI activities were measured. Analysed cheeses showed high biological activities and slight differences between them were associated with heat treatment. Our results suggested that fresh goat cheese had important biological activity due to peptides present originally in the milk or released by rennet action during cheese manufacture.

The study of the headspace components of six different samples of hand-made fresh goat's cheese smoked with dry prickly pear (Opuntia ficus indica) smoke, protected by the Palmero Denomination of Origin, was carried out. These cheeses were manufactured by six different artisans from the Island of Palma. In spite of this cheese not being a ripened cheese, more than 330 compo- nents were detected, by means of solid phase microextraction using a polyacrylate fiber followed by gas chromatography/mass spectrometry. The cheese's exterior region was the richest in compo- nents because in addition to the characteristic cheese components it also contained all those adsor- bed smoke components which had not reacted with the cheese components. The cheese's interior region was the poorest in components because only some of the smoke components had diffused towards the interior. Branched acids associated with goat's cheese flavor were not detected. In spite of the different smoking degree in the samples studied, homogeneous proportions of the main smoke phenolic derivatives were observed. Likewise, although differences in the absolute concen- trations of acids were observed, fairly homogeneous proportions of the main acids were found. The absence of terpenes and sesquiterpenes and the presence of some nitrogen derivatives as well as of syringol derivatives in significant concentrations, together with characteristic proportions of pheno- lic derivatives, allow one to distinguish this Palmero cheese from that smoked with pine needles. Opuntia ficus indica / smoked fresh goat cheese / volatile component / solid phase microextraction / gas chromatography-mass spectrometry

The composition and selected physical and chemical parameters of 44 samples of fresh goat cheeses produced on a farm in the Czech Republic were determined. The following average values were obtained for the parameters analysed: pH 4.87 ± 0.14, titratable acidity (SH) 98.09 ± 4.93, dry matter 46.83 ± 1.57%, fat in dry matter 52.74 ± 5.24%, sodium chloride (NaCl) 2.08 ± 0.54%, and a<sub>w</sub> 0.979 ± 0.007. All samples showed excellent sensory characteristics and their compositions corresponded to those declared by the producer. Microbiological tests were used for the detection of Enterobacteriaceae spp., lactic acid bacteria, Escherichia coli, Enterococcus spp., Staphylococcus aureus, Bacillus cereus, Salmonella spp. and Listeria monocytogenes. Under the applicable regulations, the analysed fresh goat’s cheeses were microbiologically safe and had the appropriate physical and chemical characteristics.

BackgroundStreptococcus equi subspecies zooepidemicus is a rare infection in humans associated with contact with horses or consumption of unpasteurized milk products. On October 23, 2003, the National Public Health Institute was alerted that within one week three persons had been admitted to Tampere University Central Hospital (TaYS) because of S. equi subsp. zooepidemicus septicaemia. All had consumed fresh goat cheese produced in a small-scale dairy located on a farm. We conducted an investigation to determine the source and the extent of the outbreak.MethodsCases were identified from the National Infectious Disease Register. Cases were persons with S. equi subsp. zooepidemicus isolated from a normally sterile site who had illness onset 15.9-31.10.2003. All cases were telephone interviewed by using a standard questionnaire and clinical information was extracted from patient charts. Environmental and food specimens included throat swabs from two persons working in the dairy, milk from goats and raw milk tank, cheeses made of unpasteurized milk, vaginal samples of goats, and borehole well water. The isolates were characterized by ribotyping and pulsed-field gel electrophoresis (PFGE).ResultsSeven persons met the case definition; six had septicaemia and one had purulent arthritis. Five were women; the median age was 70 years (range 54–93). None of the cases were immunocompromized and none died. Six cases were identified in TaYS, and one in another university hospital in southern Finland. All had eaten goat cheese produced on the implicated farm. S. equi subsp. zooepidemicus was isolated from throat swabs, fresh goat cheese, milk tank, and vaginal samples of one goat. All human and environmental strains were indistinguishable by ribotyping and PFGE.ConclusionThe outbreak was caused by goat cheese produced from unpasteurized milk. Outbreaks caused by S. equi subsp. zooepidemicus may not be detected if streptococcal strains are only typed to the group level. S. equi subsp. zooepidemicus may be a re-emerging disease if unpasteurized milk is increasingly used for food production. Facilities using unpasteurized milk should be carefully monitored to prevent this type of outbreaks.

Pathogenesis and Treatment of Hepatitis E Virus Infection

Application of spray-dried bacteriocins as cheese biopreservatives.

Background:The objective of the study was the determination of the incidence of culture-proven postoperative endophthalmitis and probable sources of infection.Materials and Methods:It was a prospective study on the microbiology, incidence and probable sources of infection in patients with postoperative infectious endophthalmitis carried out in a tertiary care eye hospital. Consecutive patients diagnosed with postoperative infectious endophthalmitis during the years 2000-2007 were investigated for the causative infective agent and possible sources of infection. The surgical data and microbiological data including the investigations performed to trace the source were recorded in a specific formatted form and were gathered and compiled for analysis.Results:Data of analysis showed that 98 (0.042%) out of 2,31,259 patients who underwent intra-ocular surgery developed infectious endophthalmitis. Among these, 70 (0.053%) occurred after cataract, 10 (0.5%) after penetrating keratoplasty (PK) and 18 (0.018%) following other types of intra-ocular surgeries. The predominant infectious agents isolated were bacteria (89.7%), with equal proportions of Gram-positive and Gram-negative bacteria. Polymicrobial infection was noted in four and fungi in seven patients. Occurrence of postoperative endophthalmitis was sporadic and not related to any specific part of period in a year. Sources of infection were donor corneal rim in six post-PK patients and phaco probe in one who had postphacoemulsification endophthalmitisConclusions:Overall incidence of postoperative endophthalmitis over an 8-year period was quite low. The sources of infection could be established in six post-PK endophthalmitis patients and in a postcataract surgery.

A proposed methodology to determine the sensory quality of a fresh goat's cheese (Cameros cheese): application to cheeses packaged under modified atmospheres

Cheese is a semi-solid or solid milk product, obtained by curdling milk and separating the curds from the whey. The examination included 46 samples of cheese produced on agriculture farms and small mini-dairies in the territory of Herzegovina, with the emphasis that most of the samples originate from the southern sub-Mediterranean and Mediterranean regions of Herzegovina. The goal of the study was to determine the microbiological safety and physicochemical quality parameters of cheeses that are marketed as fresh goat cheese, semi-solid goat cheese, and sheep and goat bellows cheese. Of the total number of analyzed samples, 49.22% did not meet the requirements of the physicochemical and microbiological parameters of the quality, where 36.22% did not meet the physicochemical quality, and 13% did not meet the microbiological quality due to an increased number of β glucuronidase positive Escherichia coli. The presence of β glucuronidase positive Escherichia coli in cheese samples indicates insufficient hygiene during the technological process of cheese production itself. Pathogenic microorganisms Salmonella spp and Listeria monocytogenes were not isolated, and the number of coagulase-positive staphylococci and Staphylococcus aureus was within the permitted limits. This study indicates that it is necessary to standardize the physicochemical parameters in the production of cheese, as well as the use of exclusively autochthonous raw materials in the production of individual small producers and in mini-dairies engaged in this production, as is the case with the industrial production of these products in that area.

Introduction: Listeria monocytogenes is an intracellular Gram-positive bacterium responsible for serious infections, especially meningoencephalitis, in immunocompromised individuals, pregnant women, and neonates. However, cases in immunocompetent individuals are rare and underdiagnosed. Case presentation: A previously healthy 34-year-old woman presented with severe headache, fever, and altered mental status. Cerebrospinal fluid (CSF) analysis revealed mononuclear pleocytosis, hypoglycorrhachia, and elevated protein levels. Culture and PCR identified Listeria monocytogenes. She was treated with ampicillin and gentamicin for 21 days, with complete recovery. Discussion: This case demonstrates Listeria 's ability to cause meningoencephalitis even in patients without predisposing factors. Dietary factors, bacterial virulence, and individual genetic susceptibility may contribute to the clinical presentation. Relevant pathophysiological, diagnostic, and therapeutic aspects are reviewed. Conclusion: Listeria monocytogenes should be considered in the differential diagnosis of subacute bacterial meningitis in young adults, especially in contexts of high-risk food exposure.

Human Parvovirus B19

Link between goat milk lipolysis and sensorial quality of lactic goat cheeses made from raw or pasteurised milk. There is an important variability of the lipolysis level in goat milk, due to various physiological and breeding factors. The aim of this study was to evaluate the impact of these natural variations on the sensorial quality of fresh and ripened lactic goat cheeses. The effect of milk pasteurisation was also studied. The results show that the variation of the lipolysis level of goat milk do not have any significant effect on the sensorial quality of ripened cheeses. On the contrary, the sensorial quality of fresh cheeses is linked to the lipolysis level of milk. These results allowed us to recommend some means of controlling the sensorial quality of goat cheeses. For ripened cheeses, a satisfying sensorial quality could be obtained via the control of the technological parameters, notably the moisture in non-fat cheese at the demoulding. For fresh cheeses, the lipolysis level of milk should be checked before cheesemaking, and milks with high lipolysis levels should not be used. Pasteurisation of milk induced a decrease in the lipolysis level of cheeses. The use of pasteurisation led to a limitation of the appearance of organoleptic defects in rip- ened cheeses, but the overall flavour and odour of ripened cheeses made from pasteurised milk was also reduced compared to cheeses made from raw milk. goat milk / lipolysis / goat cheese / sensorial quality / pasteurisation

The growth of Listeria monocytogenes in fresh goat cheese (Cameros cheese) packaged under modified atmospheres