1,721,174 research outputs found
A Rapid Enzyme-Linked Immunomagnetic Electrochemical (ELIME) Assay for the Detection of Escherichia coli O26 in Raw Milk
No full textIn this work we present a magnetic bead–based immunosensorss for the determination of Escherichia coli O26 in milk. The assay uses commercial Dynabeads® for the capture of the target bacteria from 6-h enrichment broth and horseradish peroxidase–labelled polyclonal antibodies and detection of the peroxidase activity by chronoamperometry. Bovine seroalbumin was used as blocking reagent for reducing the binding of non-specific antibodies to the beads and/or other bacteria. The effectiveness of the enzyme-linked immunomagnetic electrochemical (ELIME) assay to detect low number of E. coli O26 in milk was demonstrated using spiked milk samples from five different lots with concentrations of 9.00–18.80 or 0.90–1.88 CFU in 25 mL. Three repetitions for each concentration were analysed in parallel also by real-time PCR following the standard method ISO/TS 13136:2012, using 24-h enriched cultures. Results demonstrated that the ELIME assay can reduce the time for analyses to one working day and produce reliable results that can be confirmed by overnight cultures of the beads-bacteria complexes allowing further characterization of the virulence, including the presence of Shiga toxin–encoding genes, which is important to discriminate the enterohaemorrhagic strains
Information management and ante-mortem inspection procedures for the emerging diseases control: Experiences acquired in the epidemiological surveillance of bluetongue and lumpy skin disease
Full text linkThe spread of exotic, emerging and reemerging diseases, has become, in the last years, one of the most important threats to the animal productions and public health, representing a new challenge for the European Community. In a global-market framework, where trade and contacts between countries are simplified, effective and well-developed surveillance systems are necessary. Multiple factors are, in fact, associated with the emergence of new, known or exotic diseases in this new economic panorama and for these reasons controls on animal imports, traceability and timeliness detection of infected animals should be considered the basis of a sound surveillance. In this work, we focused our attention on the management of Bluetongue and on the risk of introduction of the Lumpy Skin Disease in Italy, in order to describe the national and European surveillance systems for these diseases. In particular, we underlined the crucial role of information that reach the Official Veterinarian at the slaughterhouse concerning the epidemiological situation of the sending countries. Information that are important for the management of the ante-mortem inspection and for increasing the awareness of the Veterinary Inspectors of their role in the surveillance
Detection and Characterization of Histamine-Producing Strains of Photobacterium damselae subsp. damselae Isolated from Mullets
Full text linkPhotobacterium damselae subsp. damselae (Pdd) is considered to be an emerging pathogen of marine fish and has also been implicated in cases of histamine food poisoning. In this study, eight strains isolated from mullets of the genera Mugil and Liza captured in the Ligurian Sea were characterized, and a method to detect histamine-producing Pdd from fish samples was developed. The histamine-producing potential of the strains was evaluated in culture media (TSB+) using a histamine biosensor. Subsequently, two strains were used to contaminate mackerel fillets (4 or 40 CFU/g), simulating a cross-contamination on the selling fish stalls. Sample homogenates were enriched in TSB+. The cultures were then inoculated on thiosulfate-citrate-bile salts-sucrose agar (TCBS) and the dark green colonies were cultured on Niven agar. The violet isolates were characterized using specific biochemical and PCR based tests. All Pdd strains were histamine producers, yielding concentration varying from 167 and 8977 µg/mL in TSB+ cultures incubated at 30 °C for 24 h. Pdd colonies were detected from the inoculated mackerel samples and their histidine decarboxylase gene was amplified using species-specific primer pairs designed for this study. The results indicate that mullets can be source of Pdd and the fish retailers needs to evaluate the risk posed by cross-contamination on the selling fish stalls
Effects of Beeswax Coating on the Oxidative Stability of Long-Ripened Italian Salami
Full text linkBeeswax coating of foods put a barrier to oxygen, light, and vapour that can help to prevent oxidation of fat and pigments and water loss. The amounts of 2-thiobarbituric acid reactive substances (TBARS) and water activity (Aw) were assessed in Italian salami coated with beeswax at 55 days of ripening and compared with controls at 5, 6, and 7 months of shelf life. The results were correlated with sensory quality. TBARS levels were below 0.8 mg kg−1 in the beeswax-coated salami until 6 months of aging (median 0.697, max 0.795) and significantly higher in the uncoated salami (median 1.176, max 1.227). A slight correlation between the amount of TBARS and Aw was observed in beeswax-coated salamis, whereas this effect was masked in controls by the large Aw variability observed at 7 months. Beeswax coating prevents case hardening and facilitated the peeling
Ozone-induced hypertussive responses in rabbits and Guinea pigs
Full text linkCough remains a major unmet clinical need, and preclinical animal models are not predictive for new antitussive agents. We have investigated the mechanisms and pharmacological sensitivity of ozone-induced hypertussive responses in rabbits and Guinea pigs. Ozone induced a significant increase in cough frequency and a decrease in time to first cough to inhaled citric acid in both conscious Guinea pigs and rabbits. This response was inhibited by the established antitussive drugs codeine and levodropropizine. In contrast to the Guinea pig, hypertussive responses in the rabbit were not inhibited by bronchodilator drugs (β2 agonists or muscarinic receptor antagonists), suggesting that the observed hypertussive state was not secondary to bronchoconstriction in this species. The ozone-induced hypertussive response in the rabbit was inhibited by chronic pretreatment with capsaicin, suggestive of a sensitization of airway sensory nerve fibers. However, we could find no evidence for a role of TRPA1 in this response, suggesting that ozone was not sensitizing airway sensory nerves via activation of this receptor. Whereas the ozone-induced hypertussive response was accompanied by a significant influx of neutrophils into the airway, the hypertussive response was not inhibited by the antiinflammatory phosphodiesterase 4 inhibitor roflumilast at a dose that clearly exhibited anti-inflammatory activity. In summary, our results suggest that ozone-induced hypertussive responses to citric acid may provide a useful model for the investigation of novel drugs for the treatment of cough, but some important differences were noted between the two species with respect to sensitivity to bronchodilator drugs.</p
Transient receptor potential ankyrin receptor 1 is a novel target for pro-tussive agents
No full textBackground and purpose: The transient receptor potential ankyrin receptor 1 (TRPA1) is a cation channel, co-expressed with the pro-tussive transient receptor potential vanilloid type 1 (TRPV1) channel in primary sensory neurons. TRPA1 is activated by a series of irritant exogenous and endogenous α,β-unsaturated aldehydes which seem to play a role in airway diseases. We investigated whether TRPA1 agonists provoke cough in guinea pigs and whether TRPA1 antagonists inhibit this response.
Experimental approach: Animals were placed in a Perspex box, and cough sounds were recorded and counted by observers unaware of the treatment used.
Key results: Inhalation of two selective TRPA1 agonists, allyl isothiocyanate and cinnamaldehyde, dose-dependently caused cough in control guinea pigs, but not in those with airway sensory nerves desensitized by capsaicin. Coughs elicited by TRPA1 agonists were reduced by non-selective (camphor and gentamicin) and selective (HC-030031) TRPA1 antagonists, whereas they were unaffected by the TRPV1 antagonist, capsazepine. Acrolein and crotonaldehyde, two α,β-unsaturated aldehydes recently identified as TRPA1 stimulants and contained in cigarette smoke, air pollution or produced endogenously by oxidative stress, caused a remarkable tussive effect, a response that was selectively inhibited by HC-030031. Part of the cough response induced by cigarette smoke inhalation was inhibited by HC-030031, suggesting the involvement of TRPA1.
Conclusions and implications: A novel pro-tussive pathway involves the TRPA1 channel, expressed by capsaicin-sensitive airway sensory nerves and is activated by a series of exogenous (cigarette smoke) and endogenous irritants. These results suggest TRPA1 may be a novel target for anti-tussive medicines
Microbiological and Modeling Approach to Derive Performance Objectives for Bacillus cereus Group in Ready-to-Eat Salads
No full textIn this article, the performance objectives (POs) for Bacillus cereus group (BC) in celery, cheese, and spelt added as ingredients in a ready-to-eat mixed spelt salad, packaged under modified atmosphere, were calculated using a Bayesian approach. In order to derive the POs, BC detection and enumeration were performed in nine lots of naturally contaminated ingredients and final product. Moreover, the impact of specific production steps on the BC contamination was quantified. Finally, a sampling plan to verify the ingredient lots' compliance with each PO value at a 95% confidence level (CL) was defined. To calculate the POs, detection results as well as results above the limit of detection but below the limit of quantification (i.e., censored data) were analyzed. The most probable distribution of the censored data was determined and two-dimensional (2D) Monte Carlo simulations were performed. The PO values were calculated to meet a food safety objective of 4 log10 cfu of BC for g of spelt salad at the time of consumption. When BC grows during storage between 0.90 and 1.90 log10 cfu/g, the POs for BC in celery, cheese, and spelt ranged between 1.21 log10 cfu/g for celery and 2.45 log10 cfu/g for spelt. This article represents the first attempt to manage the concept of PO and 2D Monte Carlo simulation in the flow chart of a complex food matrix, including raw and cooked ingredients
Chemical hazards in meat and associated monitoring activities
No full textThe various national competent authorities’ monitoring plans for residues and contaminants in meat aim at verifying compliance with the requirements set out in legislation and at investigating the reasons why violations occur. In countries with high food safety standards the number of violations is very low indeed, commonly the result of fraud and negligence in observing withdrawal periods for drugs. Data generated through official controls are used to improve the design of targeted sampling plans, so as to be more effective in detecting such sporadic violations. Pesticide residues may result from deliberate misuse, illegal use of obsolete or banned pesticides, use of sub-standard or counterfeit pesticide formulations or contamination from various sources. Geographical location has been recognized as the main factor determining the background levels of potentially toxic elements in soils. Some countries have made significant progress in the mapping of polluting activities. Very relevant is the transfer of contaminants to the farming environment by feedstuffs or landfills. Environmental contaminants in feeds may also derive from fraudulent/incorrect practices. The monitoring plans function as a ‘warning system’ for detecting problems and for verifying that precautionary measures suffice to keep levels of residues and contaminants under defined limits. At present, most veterinary drug residues in foods of animal origin occur at such low levels that chronic or long-term health hazards to consumers rarely occur. The cost-effectiveness of monitoring plans can be optimized by risk analysis. Control systems should be strengthened to reduce the probability of crises related to ‘fraudulent practices’
- …
