Application of a HACCP–QMRA approach for managing the impact of climate change on food quality and safety

The work presented focuses on predictive modelling for estimating the risk to consumers due to consumption of food contaminated with Specific Foodborne Pathogens (SFP) or estimating the remaining shelf life of the product. An approach based on integration of the existing Hazard Analysis and Critical Control Point (HACCP) approach with the Quantitative Microbial Risk Assessment (QMRA) is presented which is developed as part of the Chill-On EC FP6 research project. The paper describes the main principles of operation of the system and introduces elements of practical implementation and operation of the HACCP system combined with QMRA as well as a Shelf Life Predictor (SLP). The possibility for managing the impact of climate change by using HACCP–QMRA–SLP in supply chains is discussed.     

Intimidation

Many IS projects fail not from a lack of technical expertise but from a lack of user support and involvement. This column describes an effective method of encouraging users to participate in IS projects–the social contract.     

Sorption and diffusion properties of volatile phenols into cork

The sorption and diffusion properties of seven common volatile phenols in hydro-alcoholic medium placed in contact with natural cork were investigated to determine the influence of cork closures on the concentration of these compounds in wine. Weighted cork samples were immersed in model wine solutions containing selected concentrations of each compound and were sampled over time. Sorption coefficients ranged between 125 and 306 mg of aroma compound per kg of cork, while diffusion coefficients varied from 0.8 to 4.1 × 10⁻¹¹ m²/s. Sorption isotherms of guaiacol and 4-propylguaiacol, respectively, the lowest and highest sorbed compounds of an homologous series of guaiacol, accurately fit Henry’s model. Hydrophobicity of aroma compounds seems to be a determining factor in both diffusion and sorption. This could indicate a preferential pathway for diffusion through suberin, the more hydrophobic constituent of cork.     

Temperate and virulent Lactobacillus delbrueckii bacteriophages: Comparison of their thermal and chemical resistance

The aim of this work was to study the efficiency of diverse chemical and thermal treatments usually used in dairy industries to control the number of virulent and temperate Lactobacillus delbrueckii bacteriophages. Two temperate (Cb1/204 and Cb1/342) and three virulent (BYM, YAB and Ib3) phages were studied. The thermal treatments applied were: 63 °C for 30 min (low temperature – long time, LTLT), 72 °C for 15 s (high temperature – short time, HTST), 82 °C for 5 min (milk destined to yogurt elaboration) and 90 °C for 15 min (FIL-IDF). The chemical agents studied were: sodium hypochlorite, ethanol, isopropanol, peracetic acid, biocides A (quaternary ammonium chloride), B (hydrogen peroxide, peracetic acid and peroctanoic acid), C (alkaline chloride foam), D (p-toluensulfonchloroamide, sodium salt) and E (ethoxylated nonylphenol and phosphoric acid). The kinetics of inactivation were drew and T₉₉ (time necessary to eliminate the 99% of phage particles) calculated. Results obtained showed that temperate phages revealed lower resistance than the virulent ones to the treatment temperatures. Biocides A, C, E and peracetic acid showed a notable efficiency to inactivate high concentrations of temperate and virulent L. delbrueckii phages. Biocide B evidenced, in general, a good capacity to eliminate the phage particles. Particularly for this biocide virulent phage Ib3 showed the highest resistance in comparison to the rest of temperate and virulent ones. On the contrary, biocide D and isopropanol presented a very low capacity to inactivate all phages studied. The efficiency of ethanol and hypochlorite was variable depending to the phages considered. These results allow a better knowledge and give useful information to outline more effective treatments to reduce the phage infections in dairy plants.     

Old and endangered tomato cultivars under organic greenhouse production: effect of harvest time on flavour profile and consumer acceptance

The influence of two different harvest times (optimal and 4 days earlier) on thirty flavour compounds, titratable acid and sugars as well as consumer acceptance of four old and endangered tomato cultivars (‘Ananas’, ‘Auriga’, ‘Green Zebra’ and ‘Lukullus’) was analysed. In most cases, cultivar type had a greater effect on the volatiles profile than harvest times. Sugar contents were mostly higher at optimal harvest compared with early harvest, whereas acid content was in most cases not affected by harvest time. Consumers perceived differences in several visual and sensory aspects between cultivars as well as harvest times. The optimal harvest was regularly preferred to or at least regarded as equal to the early‐harvest time. Sensory evaluation was poorly related to the aroma volatile profile and only partly to the acid and reducing sugar contents of tomatoes. This was probably owing to the special external characteristics of the tomatoes: differing in size, shape and colour from the ‘normal’ red types.     

Computing with energy and chemical reactions

Taking inspiration from some laws of Nature—energy transformation and chemical reactions—we consider two different paradigms of computation in the framework of Membrane Computing. We first study the computational power of energy-based P systems, a model of membrane systems where a fixed amount of energy is associated with each object and the rules transform objects by manipulating their energy. We show that if we assign local priorities to the rules, then energy-based P systems are as powerful as Turing machines; otherwise, they can be simulated by vector addition systems, and hence are not universal. Then, we consider stochastic membrane systems where computations are performed through chemical networks. We show how molecular species and chemical reactions can be used to describe and simulate the functioning of Fredkin gates and circuits. We conclude the paper with some research topics related to computing with energy-based P systems and with chemical reactions.     

The influence of attrition milling on carbon dioxide sequestration on magnesium–iron silicate

Present work evaluates the structural changes in olivine (Mg,Fe)₂SiO₄ (deposit Åheim, Norway) generated by mechanical treatment as well as its adsorption properties for carbon dioxide. The high-energy attrition milling was applied for mechanical activation. Identification of the mechanically-induced changes in the mineral was carried out applying various techniques: scanning electron microscopy, Mössbauer spectroscopy, specific surface measurements, carbon dioxide adsorption and Fourier-transformed infrared spectroscopy. The observed changes in the physico-chemical properties illustrate the possibility of the applied activation to modify the surface and/or bulk properties of olivine. Sensitivity for atmospheric CO₂ sequestration as well as sequestration of CO₂ by chemisorption can be derived from the obtained results.