A qualitative risk assessment for human salmonellosis due to the consumption of fresh pork in Belgium

Although pigs contaminated with Salmonella rarely show clinical symptoms, control is important because of the public health concern. Both producers and consumers are interested in procedures for minimizing the risk of Salmonella infections. This study outlines the entire production path for fresh pork in Belgium, from farm to fork. Additionally, it describes the different critical points for Salmonella contamination, with emphasis on those steps that need extra attention and/or improvement. The data was collected by means of questionnaires at the different steps of the process. In total, 3658 questionnaires were collected, which made it possible to draw up a nationwide image of the pork production process. In the primary production phase, there are several points relating to biosecurity that can be improved in order to minimize the risk for Salmonella in fattening pigs that are sent to slaughter. In the slaughterhouse, there has been an increase in the number of pigs or carcasses that become infected with Salmonella. Attention should be paid to avoiding contact of the feces and tonsils of contaminated pigs with the carcass, and strict hygienic measures should be taken to avoid cross-contamination. During the transformation and distribution of the carcasses, there is a low risk of further spreading of Salmonella spp. Finally, during the consumer phase, the risk for Salmonella contamination increases because of inappropriate temperature conditions during storage, manipulation of the meat and possible cross-contamination with other food products, and the consumption of insufficiently heated and/or raw meat. The present study illustrates that the risk of Salmonella infection by consumption of fresh pork is relatively low under Belgian conditions. Nevertheless, it can be further decreased by implementing additional control measures, mainly in the slaughterhouse and in the domestic kitchen

Monitoring of activated sludge settling ability through image analysis : validation on full-scale wastewater treatment plants

In recent years, a great deal of attention has been focused on the research of activated sludge processes, where the solid–liquid separation phase is frequently considered of critical importance, due to the different problems that severely affect the compaction and the settling of the sludge. Bearing that in mind, in this work, image analysis routines were developed in Matlab environment, allowing the identification and characterization of microbial aggregates and protruding filaments in eight different wastewater treatment plants, for a combined period of 2 years. The monitoring of the activated sludge contents allowed for the detection of bulking events proving that the developed image analysis methodology is adequate for a continuous examination of the morphological changes in microbial aggregates and subsequent estimation of the sludge volume index. In fact, the obtained results proved that the developed image analysis methodology is a feasible method for the continuous monitoring of activated sludge systems and identification of disturbances.Empresa de Águas, Efluentes e Resíduos de Braga, Portugal - EM (AGERE)Fundação para a Ciência e a Tecnologia (FCT

Quantitative image analysis for the characterization of microbial aggregates in biological wastewater treatment : a review

Quantitative image analysis techniques have gained an undeniable role in several fields of research during the last decade. In the field of biological wastewater treatment (WWT) processes, several computer applications have been developed for monitoring microbial entities, either as individual cells or in different types of aggregates. New descriptors have been defined that are more reliable, objective, and useful than the subjective and time-consuming parameters classically used to monitor biological WWT processes. Examples of this application include the objective prediction of filamentous bulking, known to be one of the most problematic phenomena occurring in activated sludge technology. It also demonstrated its usefulness in classifying protozoa and metazoa populations. In high-rate anaerobic processes, based on granular sludge, aggregation times and fragmentation phenomena could be detected during critical events, e.g., toxic and organic overloads. Currently, the major efforts and needs are in the development of quantitative image analysis techniques focusing on its application coupled with stained samples, either by classical or fluorescent-based techniques. The use of quantitative morphological parameters in process control and online applications is also being investigated. This work reviews the major advances of quantitative image analysis applied to biological WWT processes.The authors acknowledge the financial support to the project PTDC/EBB-EBI/103147/2008 and the grant SFRH/BPD/48962/2008 provided by Fundacao para a Ciencia e Tecnologia (Portugal)