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ObjectiveTo investigate the etiological features and traceability of a food poisoning incident in Pudong District， Shanghai， and to provide a basis for the future investigation and disposal of similar incidents.MethodsAnal swabs of the patients and a chef and food residues were collected for pathogens isolation and identification. Enterotoxin detection immunosorbent assay （ELISA）， drug sensitivity test， pulsed field gel electrophoresis （PFGE） and multilocus sequence typing （MLST） were used for genotyping and tracing.ResultsNine anal swabs from patients， one anal swab from the chef， and 3 food residues were positive for Staphylococcus aureus （S. aureus）. Ten isolates from patients and the chef carried Staphylococcus enterotoxin （SE） A and SEE， while 3 isolates from food carried SEA， SED and SEE. All the isolates were resistant to penicillin. The S. aureus strains from the case shared the same PFGE pattern and the MLST type of them belonged to ST6.ConclusionThe cause of this food poisoning outbreak was S. aureus contamination. It is necessary to further strengthen the education and management of food processing enterprises， canteens， etc. to prevent similar incidents.

ObjectiveAn epidemiological investigation and analysis of a food poisoning incident at a school in Pudong New Area was conducted to identify the pathogenic factors, pathogenic food and the source of contamination, and to taken effective control measures and provided reference for the disposal of similar incidents in future.MethodsA descriptive epidemiological method was used to analyze the epidemiological characteristics of the incident; a case-control study was used to analyze the suspicious food; interview and on-the-spot investigation were used to conduct food hygiene investigation to understand the process of food production, transportation, storage and raw material sources; samples of anal swabs, food, processing links and drinking water were collected for laboratory testing.ResultsFifty-one suspected cases were found, and the clinical manifestations were mainly diarrhea, fever, abdominal pain, headache, nausea and vomiting. The incubation period of onset ranged from 2.5 to 5.1 h, with a median of 20 h. The case-control analysis found that the sandwich at breakfast on September 4th, 2018 was the suspect high-risk food. Salmonella was detected in the samples of anal swab from 7 cases. Molecular typing analysis of the positive strains of Salmonella by pulsed field gel electrophoresis indicated that they were from the same source of infection, and there was a situation of simultaneous infection of multiple types of Salmonella.ConclusionThis was an incident of food poisoning caused by Salmonella, and the suspect food was sandwich. It is suggested that school catering units should strengthen the examination of food supply, strictly implement the sample retention system and implement various food safety measures.

A disassembly line is an effective disassembly system to recover end-of-life products. In real life, as end-of-life products are subject to varying degrees of wear and tear, task failure may occur in the disassembly process. In this paper, the task failure risks are considered, and an expected profit-based stochastic disassembly line balancing problem is studied. First, a mathematical model is presented to maximise the expected recovering profit with task failures. Then, a hybrid metaheuristic approach is developed to efficiently solve the proposed model, which is integrated with a variable neighbourhood descent method and an artificial bee colony algorithm. Finally, the effectiveness and robustness of the proposed algorithm are verified by three cases, and experiment results show that the solution performance of the proposed approach is superior to the other three existing methods. [ABSTRACT FROM AUTHOR]

To overcome disability and default in process quality control and failure of traditional quality management in job shop manufacturing and customised orders, which are important issues in lean production, we investigate a sustainable quality control of plant-wide production process. In this paper, we construct the mechanisms consisting of pre-production quality prevention, quality control of production process and post-production feedback, using modified turtle diagram and VDA-based evaluation model. After the application of the mechanism in a large heavy truck enterprise in Chine for three years, the average benefit of the enterprise reached 36.58 million yuan, the gross loss of the single after-sales service decreased by 37.4%, and the net loss decreased by 21.1%, which indicates improvement of capacity of sustainable development. Case above in our paper shows that the mechanism we put forward is effective and practical for continuous improvement of quality management and sustainable development of enterprises. Besides, it provides a further supplement to existing lean production theory. [ABSTRACT FROM AUTHOR]

With the rapid development of computer technology and related softwares for mathematical models, mathematical modelling of scheduling problems is receiving growing attention from researchers. In this work, the hybrid flow shop scheduling problem with unrelated parallel machines (HFSP-UPM) with the objective aimed to minimise the makespan is studied. According to the characteristics of the HFSP-UPM, eight mixed integer linear programming (MILP) models are formulated in order to obtain optimal solutions based on different modelling ideas. Then, these models are extended to solve HFSP-UPM with sequence-dependent setup times (HFSP-UPM-SDST), no-wait HFSP-UPM (HFSP-UPM-NW) and HFSP-UPM with blocking (HFSP-UPM-B). All the proposed models and the existing model are detailedly compared and evaluated under three aspects namely modelling process, size complexity and computational complexity. Numerical experiments show that MILP models dependent on diverse modelling ideas perform very differently. The model developed based on stage precedence is the best one and should be given preference in future applications. In addition, the proposed models of HFSP-UPM-NW and HFSP-UPM-B improve several best known solutions for the test instances in the existing literature. [ABSTRACT FROM AUTHOR]

This paper investigates an energy-conscious hybrid flow shop scheduling problem with unrelated parallel machines (HFSP-UPM) with the energy-saving strategy of turning off and on. We first analyse the energy consumption of HFSP-UPM and formulate five mixed integer linear programming (MILP) models based on two different modelling ideas namely idle time and idle energy. All the models are compared both in size and computational complexities. The results show that MILP models based on different modelling ideas vary dramatically in both size and computational complexities. HFSP-UPM is NP-Hard, thus, an improved genetic algorithm (IGA) is proposed. Specifically, a new energy-conscious decoding method is designed in IGA. To evaluate the proposed IGA, comparative experiments of different-sized instances are conducted. The results demonstrate that the IGA is more effective than the genetic algorithm (GA), simulating annealing algorithm (SA) and migrating birds optimisation algorithm (MBO). Compared with the best MILP model, the IGA can get the solution that is close to an optimal solution with the gap of no more than 2.17% for small-scale instances. For large-scale instances, the IGA can get a better solution than the best MILP model within no more than 10% of the running time of the best MILP model. [ABSTRACT FROM AUTHOR]