Marianne Sindic

Hygiene and Cleanability: A Focus on Surfaces

Hygiene is a permanent concern for food industries since they must commercialize high quality products in order to comply with the legislation and the expectations of the consumers. The hygienic state of a surface is thus a critical parameter with respect to the performances of the production process and to the final quality of the product. For this reason, cleaning and disinfection are essential. However, the efficiency of the cleaning process will not only depend on the optimization of the process by itself and on the equipment design but also on the characteristics of the soiled surface i.e. mainly its roughness, surface chemical composition, and surface energy. The relation between these parameters and the cleanability are presented here, mainly for food applications. Some examples of existing easy-to-clean and self-cleaning surfaces based on the modification of these surface parameters are also presented.

Chemical composition and antioxidant activity of essential oil, various organic extracts of Cistus ladanifer and Cistus libanotis growing in Eastern Morocco

In the present work, we studied the chemical composition of the essential oil of Cistus ladanifer and Cistus libanotis growing in Eastern Morocco. The essential oils were obtained by hydrodistillation and their chemical composition was analysed using gas chromatography- mass spectrometry (GC–MS). Camphene, borneol, cyclohexanol-2, 2, 6 tremethyl, terpineol-4 and α-pinene were the main constituents of the essential oil of C. ladanifer, while in the essential oil of C. libanotis we obtained terpineol-4, γterpinene, camphene, sabinene, α-terpinene and α-pinene. The antioxidant potential of various extracts (water, ethanol, ethanol: water (50:50), methanol, methanol: water (50:50), acetonitrile) and essential oils of C. ladanifer and C. libanotis were carried out by the method of 1,1-diphenyl-1-picrylhydrazylhydrate (DPPH) free radical scavenging. Total phenolic and flavonoid contents were determined. The result show that C. ladanifer of the leaves of methanol: water (50:50) extract had the highest value of total phenolic content and the lowest was present in ethanol: water (50:50) extract of the stem and acetonitrile extract of the flowers of C. libanotis. From our experimental results, the extract of flowers, fruit, stem and leaves of those plants showed highest potential as free radical scavengers.

Physico-chemical mechanisms governing the adherence of starch granules on materials with different hydrophobicities.

The factors influencing the adherence of starch were examined to improve the understanding of the mechanisms affecting soiling and cleanability. Therefore an aqueous suspension of starch granules was sprayed on four model substrates (glass, stainless steel, polystyrene and PTFE) and dried, and the substrates were cleaned using a radial-flow cell. The morphology of the soiled surfaces and the substrate chemical composition were also characterized. By influencing droplet spreading and competition between granule-substrate and granule-granule interfaces regarding the action of capillary forces, substrate wettability affected the shape and compactness of the adhering aggregates, the efficiency of shear forces upon cleaning, and finally the adherence of soiling particles. The rate of drying had an influence explained by the duration left to capillary forces for acting. X-ray photoelectron spectroscopy demonstrated the presence of macromolecules, mainly polysaccharides, which were adsorbed from the liquid phase, or carried by the retracting water film and deposited at the granule-substrate interface. These macromolecules acted as an adhesive joint, the properties of which seemed to be influenced by the detailed history of drying and subsequent exposure to humidity. In summary, the substrate surface energy affects the adherence of starch aggregates by different mechanisms which are all linked together: suspension droplet spreading, action of capillary forces, direct interaction with starch particles and interfacial macromolecules.

Conditioning materials with biomacromolecules: composition of the adlayer and influence on cleanability

The influence of substrate hydrophobicity and biomacromolecules (dextran, bovine serum albumin - BSA) adsorption on the cleanability of surfaces soiled by spraying aqueous suspensions of quartz particles (10-30μm size), then dried, was investigated using glass and polystyrene as substrates. The cleanability was evaluated using radial flow cell (RFC). The surface composition was determined by X-ray photoelectron spectroscopy (XPS). The interpretation of XPS data allowed the complexity due to the ubiquitous presence of organic contaminants to be coped with, and the surface composition to be expressed in terms of both the amount of adlayer and the mass concentration of adlayer constituents. When soiled with a suspension of particles in water, glass was much less cleanable than polystyrene, which was attributed to its much lower water contact angle, in agreement with previous observations on starch soil. Dextran was easily desorbed and did not affect the cleanability. The presence of BSA at the interface strongly improved the cleanability of glass while the contact angle did not change appreciably. In contrast, soiling polystyrene with quartz particles suspended in a BSA solution instead of water did not change markedly the cleanability, while the contact angle was much lower and the aggregates of soiling particles were more flat. These observations are explained by the major role of capillary forces developed upon drying, which influence the closeness of the contact between the soiling particles and the substrate and, thereby, the adherence of particles. The capillary forces are proportional to the liquid surface tension and depend in a more complex way on contact angles of the particles and of the substrate. The dependence of cleanability on capillary forces, and in particular on the liquid surface tension, is predominant as compared with its dependence on the size and shape of the soiling aggregates, which influence the efficiency of shear forces exerted by the flowing water upon cleaning.

High pressure-induced gel formation of chicken meat patties

Abstract High pressure treatments produce gelified chicken meat patties with new properties (high water retention and cohesive texture) and without salt or fat addition. In comparison with heat-induced patties, the pressurised patties present an equivalent hardness with better water binding properties. Pressurisation causes an increase of the colour lightness parameter (L*) and a decrease of redness (a*) and yellowness (b*); but the meat discoloration provoked by the pressure treatments is less significant than the colour changes induced by heating. The pressure-gelation of chicken meat patties is affected by the intensity, the duration and the temperature of the process. The elevation of pressure from 400 to 600 MPa enhances the texture qualities and the water binding capacity of formed gels. A positive effect on texture quality is observed by prolonging the pressurisation time up to 30min. The pressurisation temperature (between 15 and 40°C) has no effect on product quality. Addition of salt (fat) prevents (reduces) the gelation ability of meat patties under pressure, whereas it improves the texture of heat-induced gels.

Microbiological safety and quality aspects of the short supply chain: SWOT analysis of the Belgian case study

Purpose – In recent years consumers in Belgium have shown a great interest for foods from the short supply chain. The difference with the conventional chain is that in the short supply chain the primary products are locally processed and sold directly by the producer to the consumer. The short supply chain has different microbiological quality and safety aspects in comparison with the conventional chain. The purpose of this paper is to evaluate these aspects. Design/methodology/approach – The methodology consists of analyzing the available scientific literature and results of microbiological analyses on foods from the short supply chain. Findings – The main findings were that Listeria monocytogenes was frequently detected (15 percent) in sampled raw dairy products whereas Salmonella was not isolated in 1,023 samples. Human pathogenic vero (cyto) toxin-producing Escherichia coli and Campylobacter spp. are potential hazards, in particular for products that are not thermally treated. Data with regard to E. c...

Possible Influence of Surfactants and Proteins on the Efficiency of Contact Agar Microbiological Surface Sampling

Agar contact microbiological sampling techniques, based on a transfer of the microorganisms present on a surface to a culture medium, are widely used to assess and control surface cleanliness and to evaluate microbial contamination levels. The effectiveness of these techniques depends on many environmental parameters that influence the strength of attachment of the bacteria to the surface. In the present study, stainless steel and high density polyethylene surfaces were inoculated with known concentrations of Staphylococcus epidermidis. Following an experimental design, the surfaces were sampled with different types of replicate organism direct agar contact plates and Petrifilm; results indicated that recovery rates were influenced by the presence of egg white albumin or Tween 80 in the inoculum solutions or by the introduction of surfactants into the contact agar of the microbiological sampling techniques. The techniques yielded significantly different results, depending on sampling conditions, underlining the need for a standardization of laboratory experiments to allow relevant comparisons of such techniques.

Prevalence and survival of Listeria monocytogenes in various types of cheese-A review

26 Since the publication of Regulation (EC) N°2073/2005, RTE food allowing the development of Listeria 27 monocytogenes, including cheese, have to be exempt of the pathogen in 25g. This review was carried out in 28 order to gather studies on the prevalence of the pathogen in various types of cheese in Europe, while also 29 including data about the situation in other continents. Given that Regulation (EC) N°2073/2005 distinguishes 30 cheeses allowing or not the survival of L. monocytogenes based on pH and water activity (aw), the review also 31 focuses on the determinants of this growth/no growth in the same types of cheese. 32 33

Flowering, a Critical Phenological Stage as a Limiting Factor for Almond Native Ecotypes Cultivation in Eastern Morocco

Almond is the most important nut crops in Morocco with an area of 151 kha and an average production of 99,000 tons (Houmy et al., 2016; MAPM, 2014). Almond Branch in eastern Morocco is supported by a Belgium program for agriculture and rural development (PROFAO 2011-2017). The aim of this project is to expand the growing area of the almond tree by planting 6,000 ha of new orchards and by installing new units for crushing almonds in shell. Ferragnes/ Ferraduel (F/F) is the main couple of new introduced varieties due to their late blooming in March permitting to escape the adverse effects of January and February frosts. Currently, this region benefits from another project which is considered a continuation of the PROFAO and aims to develop the almond sector by the characterization of cultivated varieties and the valorization of their final products. Thus this preliminary study concerns (i) the observation of two biological parameters of local ecotypes “Beldi” which are typically considered to be early flowering almond trees. (ii) Due to their small size and narrow shape, these local almond nuts are mainly used to produce almond oils for cosmetic uses. Thus because the fruits of these Beldi almond ecotypes are mainly used for almond’s oil extraction, we compare the oils of these Beldi almonds to those of the newly introduced varieties “Ferragnes/Ferraduel”.

Effect of the sowing date on physicochemical and fonctional properties of native starches extracted from European soft wheat (Triticum aestivum L.)

The influence of wheat sowing dates on the starch properties was evaluated during several growing seasons (2002 to 2005). Some European wheat varieties were sown at 2 distinct dates, cultivated in the same growing conditions and simultaneously harvested. The comparison of the 4 harvest seasons shows globally the same observations and the results of 2005 harvest are presented in this paper. A significant impact of the sowing date on the starch properties are measured for most of the studied varieties. An appropriate selection of the wheat variety and its sowing date could be valorized to emphasize starch properties researched in industrial end uses. Furthermore, these variations between the starch characteristics could lead to processing or end-products quality problems.