The Mast Cell Degranulator Compound 48/80 Directly Activates Neurons

Background Compound 48/80 is widely used in animal and tissue models as a “selective” mast cell activator. With this study we demonstrate that compound 48/80 also directly activates enteric neurons and visceral afferents. Methodology/Principal Findings We used in vivo recordings from extrinsic intestinal afferents together with Ca++ imaging from primary cultures of DRG and nodose neurons. Enteric neuronal activation was examined by Ca++ and voltage sensitive dye imaging in isolated gut preparations and primary cultures of enteric neurons. Intraluminal application of compound 48/80 evoked marked afferent firing which desensitized on subsequent administration. In egg albumen-sensitized animals, intraluminal antigen evoked a similar pattern of afferent activation which also desensitized on subsequent exposure to antigen. In cross-desensitization experiments prior administration of compound 48/80 failed to influence the mast cell mediated response. Application of 1 and 10 µg/ml compound 48/80 evoked spike discharge and Ca++ transients in enteric neurons. The same nerve activating effect was observed in primary cultures of DRG and nodose ganglion cells. Enteric neuron cultures were devoid of mast cells confirmed by negative staining for c-kit or toluidine blue. In addition, in cultured enteric neurons the excitatory action of compound 48/80 was preserved in the presence of histamine H1 and H2 antagonists. The mast cell stabilizer cromolyn attenuated compound 48/80 and nicotine evoked Ca++ transients in mast cell-free enteric neuron cultures. Conclusions/Significance The results showed direct excitatory action of compound 48/80 on enteric neurons and visceral afferents. Therefore, functional changes measured in tissue or animal models may involve a mast cell independent effect of compound 48/80 and cromolyn

Bacillus cereus

© 2014 Elsevier Ltd. All rights reserved. Bacillus cereus food poisoning is the general description of illness associated with this organism, although two recognized types of illness are caused by two distinct metabolites (toxins). The diarrheal type of illness is caused by a large-molecular-weight protein and the vomiting (emetic) type of illness is associated with cereulide, an acid- and heat-resistant polypeptide. Bacillus cereus is member of a group of closely related organisms, the B. cereus complex. Work aimed at understanding the relationships between members of the complex, and on their characteristics and mechanisms of pathogenicity, has been extensive. The occurrence of these organisms in foods and the means by which they can be controlled are considered in this article

Application of heat in postcook meat chillers reduces listeria

Electrical air-blowing heaters were used to heat and dry out holding chillers used for postcook commercial processed meats in an attempt to control the presence of Listeria. A baseline study of the prevalence of Listeria in holding chillers in seven facilities was undertaken. Listeria was detected in four of the seven chillers, and swab samples showed Listeria prevalence ranging from 7 (7.8%) of 90 to 6 (20%) of 30, depending on the facility. Two of the facilities with established Listeria contamination (A and E) were chosen for further studies. The heating trials consisted of three individual heating interventions at each of the two facilities, with 2 weeks of postintervention sampling after each treatment. The initial Listeria prevalence in chiller A was 19 (10.6%) of 180, and treatment at 37°C for 36 h reduced prevalence to 3 (1.7%) of 180. The initial Listeria prevalence in chiller E was 7 (7.8%) of 90, and treatment at 50°C for 2 h reduced prevalence to 0 of 90. Both reductions were statistically significant at P < 0.01. The incorporation of these two simple chiller heating protocols into these facilities' good manufacturing practices has effectively reduced prevalence of Listeria in chillers

Hazard analysis critical control point and self-regulation

© 2014 Elsevier Ltd. All rights reserved. As the responsibility of food manufacturers for the safety of their products increases, self-regulatory systems that effectively control food safety risks will undoubtedly proliferate. Food processors and food inspection authorities must cooperate in systematically implementing these systems if they are to be effective. The systems described here, namely good manufacturing practices, hazard analysis critical control point, and failure mode and effect analysis, are only a few of the large number of management tools that can be used for assuring food safety

Reduction of environmental Listeria using gaseous ozone in a cheese processing facility

Copyright ©, International Association for Food Protection. A cheese processing facility seeking to reduce environmental Listeria colonization initiated a regime of ozonation across all production areas as an adjunct to its sanitation regimes. A total of 360 environmental samples from the facility were tested for Listeria over a 12-month period. A total of 15 areas before and 15 areas after ozonation were tested. Listeria isolations were significantly (P &lt; 0.001) reduced from 15.0% in the preozonation samples to 1.67% in the postozonation samples in all areas. No deleterious effects of ozonation were noted on the wall paneling, seals, synthetic floors, or cheese processing equipment. The ozonation regime was readily incorporated by sanitation staff into the existing good manufacturing practice program. The application of ozone may result in a significant reduction in the prevalence of Listeria in food processing facilities

Environmental Legionella spp. collected in urban test sites of South East Queensland, Australia, are virulent to human macrophages in vitro

© 2015 Institut Pasteur. Legionellae are frequent contaminants of potable water supplies, resulting in sporadic infections and occasional outbreaks. Isolates of Legionella were collected from urban test sites within South East Queensland and evaluated for their virulence potential in vitro. Two strains (from the species Legionella londiniensis and Legionella quinlivanii) were demonstrated to have the ability to infect human macrophages, while a strain from the species Legionella anisa did not maintain an infection over the same time course. This suggests that the spectrum of urban environmentally associated Legionella with potential to cause human disease might be greater than currently considered

Genetic characterization of Listeria monocytogenes isolates from food processing facilities before and after postcook chiller heat treatment

Possible selection for and establishment of stress-resistant Listeria monocytogenes variants as a consequence of heating interventions is of concern to the food industry. Lineage analysis and multilocus variable number tandem repeat analysis (MLVA) was performed on 20 L. monocytogenes isolates, of which 15 were obtained before and 5 were obtained after heat treatment of a postcook meat chiller. The ctsR gene (a class III heat shock gene regulator) from 14 isolates was amplified and sequenced because previous work has indicated that spontaneous mutations can occur in this gene during heat treatment. Heat treatment of the meat chiller did not significantly change the relative abundance of the various L. monocytogenes lineages; lineage II strains (less-heat-resistant isolates) dominated both before and after heat treatment. MLVA typing confirmed that some isolates of L. monocytogenes occur both before and after heat treatment of the chiller. No isolate of L. monocytogenes indicated any likely functionally significant mutations in ctsR. This study indicates the absence of any obvious difference in the profiles of L. monocytogenes strains obtained before and after heat treatment of a meat chiller, based on the characteristics examined. Although this finding supports the effectiveness of heat treatment, the limited number of strains used and characteristics examined mean that further study on a larger scale is required before firm conclusions can be drawn