Blast-cooling of beef-in-sauce catering meals: numerical results based on a dynamic zeroorder model

International audienceBeef-in-sauce catering meals under blast-cooling have been investigated in a research project which aims at quantitative HACCP (hazard analysis critical control point). In view of its prospective coupling to a predictive microbiology model proposed in the project, zero-order spatial dependence has proved to suitably predict meal temperatures in response to temperature variations in the cooling air. This approach has modelled heat transfer rates via the a priori unknown convective coefficient hc which is allowed to vary due to uncertainty and variability in the actual modus operandi of the chosen case study hospital kitchen. Implemented in MS Excel®, the numerical procedure has successfully combined the 4th order Runge-Kutta method, to solve the governing equation, with non-linear optimization, via the built-in Solver, to determine the coefficient hc. In this work, the coefficient hc was assessed for 119 distinct recently-cooked meal samples whose temperature-time profiles were recorded in situ after 17 technical visits to the hospital kitchen over a year. The average value and standard deviation results were hc = 12.0 ± 4.1 W m-2 K-1, whilst the lowest values (associated with the worst cooling scenarios) were about hc » 6.0 W m-2 K-1

Chaîne du froid des denrées réfrigérées en France

International audienceThis paper presents the results of a cold chain field study in France in 2013 carried out in the framework of a European project named Frisbee. A comparison with the results obtained in a previous field study in France in 2002 was presented. These two studies enabled us to have a real picture of the cold chain because temperature monitoring was carried out in a manner not visible to operators and consumers. These studies concern the cold chain of chilled products from the production plant to storage in a domestic refrigerator. The Frisbee field study confirms the results observed in previous work that the most sensitive links are transportation after purchase and particularly storage in a household refrigerator. Despite the regulation imposed by the French authorities since 2002 to indicate the cold zone in refrigerators where sensitive products should be placed, the preservation of products at home is still problematic

Évaluation quantitative des risques combinant la sécurité des aliments, les gaspillages et la consommation énergétique : une prochaine étape de développement de la chaine du froid ?

International audienceThe preservation of perishable food via refrigeration in the supply chain is essential to extend shelf life and provide consumers with safe food. However, electricity consumed in refrigerationprocesses has an economical and an environmental impact. This study focuses on the cold chain of cooked ham, including transport, cold room in supermarket, display cabinet, transport by consumer, and domestic refrigerator, and aims to predict the risk for human health associated with Listeria monocytogenes, the amount of food wasted due to the growth of spoilage bacteria, and the electrical consumption to maintain product temperature through the cold chain. A set of eight intervention actions were tested to evaluate their impact on the three criteria. Results show that the modification of the thermostat of the domestic refrigerator has a high impact on food safety and food waste and a limited impact on the electrical consumption. Inversely, the modification of the airflow rate in the display cabinet has a high impact on electrical consumption and a limited impact on food safety and food waste.A cost-benefit analysis approach and two multicriteria decision analysis methods were used to rank the intervention actions. These three methodologies show that setting the thermostatof the domestic refrigerator to 4 °C presents the best compromise between the three criteria. The impact of decisionmaker preferences (criteria weight) and limitations of these three approaches are discussed. The approaches proposed by this study may be useful in decision making to evaluate global impact of intervention actions in issues involving conflictingoutputs

Analyse multicritère considérant la sécurité des aliments, gaspillages et consommation énergétique: Application au procédé de production des pâtes ménagères

International audienceThe preservation of perishable food via cold supply chain is essential to extend shelf life and ensure food safety. However, the use of refrigeration processes requires energy consumption with economic and environmental impact. Increasing the temperature set point in cold equipment could save energy, but the global cost may increase due to food waste or safety issues. The study of potentially conflicting objectives such as food safety, food waste, and energy consumption may be challenging because the comparison between the outcomes of those objectives (risk of illness, amount of food waste, energy consumption in kWh). Methodologies leading to overcome issues involving conflicting impacts and the knowledge of their limitations are essential to support decision makers. This study focuses on the modeling of the energy consumption of cold facilities, food temperature, food contamination and growth of Listeria monocytogenes and lactic acid bacteria in a puff pastry plant. An event based framework was used to model the main components of the production line (kneader, conveyor, cooling spiral and cold room). Own-checks (microbial and temperature) data from food industry premises were used to inform and parameterize the model. Different scenarios were tested to evaluate the impact of operating conditions (setting temperature and duration) on energy consumption, food waste and food safety. Results showed that the temperature setting of the cooling spiral had a low impact on energy consumption and a high impact on the microbial quality. The opposite phenomena were observed in the cold room with a moderate impact of the cold room temperature setting on the food microbial quality and a high impact on energy consumption. Finally, a multi-criteria decision analysis approach is proposed to identify the optimal operating conditions regarding the three criteria. Criteria weights were set by the operators of the food plant (quality manager, production manager, energy advisor and plant director). This methodology helps manufacturers in decision making to optimize operating conditions and reduce energy consumption with a limited impact on food waste and safety