Showing papers by "Frank Devlieghere published in 2015"

Moisture sorption isotherms and thermodynamic properties of whole black peppercorns (Piper nigrum L.)

Abstract: Adsorption and desorption isotherms for whole black peppercorns ( Piper nigrum L.) were developed at 22, 30 and 37 °C using standard static gravimetric method. The sorption isotherms exhibited a type III behaviour according to Brunauer-Emmett-Teller (BET) classifications. The equilibrium moisture content (EMC) decreased with increasing temperature at a particular water activity (a w ). Hysteresis existed over the entire a w range at 30 and 37 °C. At 22 °C, an intersection of the curves was found at a w closer to 0.75. The goodness of fit of the models was evaluated using several statistical indices and residual plots. The Guggenheim-Anderson-de Boer (GAB) and Peleg models were determined to best describe the experimental sorption data. The monolayer moisture content ( M 0 ) were 4.78, 3.56 and 3.49 g/100 g at 22, 30 and 37 °C for adsorption. The maximum isosteric heat of sorption was 28.1 and 73.3 kJ/mol for adsorption and desorption, respectively. The net isosteric heat of sorption and sorption entropy increased with increase in EMC; both curves dropped off exponentially after M 0 . The Gibbs free energy change for adsorption ranged from 100.6 to 9370.6 J/mol. The black peppercorns can be stored at 22, 30 and 37 °C, by reducing their MC to 10, 8 and 7 g/100 g, respectively, with a w below 0.60.

Heat resistance of new biobased polymeric materials, focusing on starch, cellulose, PLA, and PHA

Abstract: This review provides state of the art information on the heat resistance of biobased thermoplastic materials. It gives an overview of the parameters used to indicate heat resistance, strategies to improve the heat resistance of (biobased) plastic materials and some current “heat resistant” commercially available biobased plastics materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42305.

Processing Environment and Ingredients Are Both Sources of Leuconostoc gelidum, Which Emerges as a Major Spoiler in Ready-To-Eat Meals.

Abstract: Mesophilic and psychrotrophic organism viable counts, as well as high-throughput 16S rRNA gene-based pyrosequencing, were performed with the aim of elucidating the origin of psychrotrophic lactic acid bacteria (LAB) in a ready-to-eat (RTE) meal manufacturing plant. The microbial counts of the products at the end of the shelf life were greatly underestimated when mesophilic incubation was implemented due to overlooked, psychrotrophic members of the LAB. Pseudomonas spp., Enterobacteriaceae, Streptococcaceae, and Lactobacillus spp. constituted the most widespread operational taxonomic units (OTUs), whereas Leuconostoc gelidum was detected as a minor member of the indigenous microbiota of the food ingredients and microbial community of the processing environment, albeit it colonized samples at almost every sampling point on the premises. However, L. gelidum became the most predominant microbe at the end of the shelf life. The ability of L. gelidum to outgrow notorious, spoilage-related taxa like Pseudomonas, Brochothrix, and Lactobacillus underpins its high growth dynamics and severe spoilage character under refrigeration temperatures. The use of predicted metagenomes was useful for observation of putative gene repertoires in the samples analyzed in this study. The end products grouped in clusters characterized by gene profiles related to carbohydrate depletion presumably associated with a fast energy yield, a finding which is consistent with the fastidious nature of highly competitive LAB that dominated at the end of the shelf life. The present study showcases the detrimental impact of contamination with psychrotrophic LAB on the shelf life of packaged and cold-stored foodstuffs and the long-term quality implications for production batches once resident microbiota are established in the processing environment.

Growth and inactivation of Salmonella enterica and Listeria monocytogenes in broth and validation in ground pork meat during simulated home storage abusive temperature and home pan-frying.

Abstract: Ground pork meat with natural microbiota and inoculated with low initial densities (1-10 or 10-100 CFU/g) of Salmonella enterica or Listeria monocytogenes was stored under abusive temperature at 10°C and thermally treated by a simulated home pan-frying procedure. The growth and inactivation characteristics were also evaluated in broth. In ground pork meat, the population of S. enterica increased by less than one log after 12-days of storage at 10°C, whereas L. monocytogenes increased by 2.3 to 2.8 log units. No unusual intrinsic heat resistance of the pathogens was noted when tested in broth at 60°C although shoulders were observed on the inactivation curves of L. monocytogenes. After growth of S. enterica and L. monocytogenes at 10°C for 5 days to levels of 1.95 log CFU/g and 3.10 log CFU/g, respectively, in ground pork meat, their inactivation in the burger subjected to a simulated home pan-frying was studied. After thermal treatment S. enterica was undetectable but L. monocytogenes was recovered in three out of six of the 25 g burger samples. Overall, the present study shows that data on growth and inactivation of broths are indicative but may underestimate as well as overestimate behavior of pathogens and thus need confirmation in food matrix conditions to assess food safety in reasonably foreseen abusive conditions of storage and usual home pan-frying of of meat burgers in Belgium.

A new protocol for evaluating the efficacy of some dispensing systems of a packaging in the microbial protection of water-based preservative-free cosmetic products.

Abstract: Synopsis Objective A new protocol is described for assessing the efficacy of the dispenser of some packaging systems (PSs) of preservative-free cosmetic products in protecting both their contained formula and their delivered doses. Methods Practically, aiming at mimicking contacts with a non-sterile skin or fingers, the dispensing system is put into contact with a pre-contaminated fabric by a standardized colonization of P. aeruginosa. Results When applied to three different types of packaging, results show clear differences in both criteria between these conditioning articles, that is variable efficacies in protecting the contained product and the delivered doses, knowing that the first aspect is of paramount importance. Conclusion The proposed protocol is proved being able to discriminate between different PSs and provides information on strong and weak features of certain types dispensing technologies prone to efficiently decrease either the dose contamination or to prevent contamination in reaching the contained product. Therefore, the proposed protocol can contribute to an objective selection of a PS for protecting a cosmetic care product with a low content of preservative or preservative free. Resume Objectif Un nouveau protocole est decrit pour evaluer l'efficacite du distributeur de certains systemes d'emballage (PS) des produits cosmetiques sans conservateurs pour proteger a la fois leur formule contenue et leurs doses delivrees. Methodes Pratiquement, visant a mimer les contacts avec les doigts ou une peau non sterile, le systeme de distribution est mis en contact avec un tissu pre-contamine par une colonisation normalisee de P. aeruginosa. Resultats Lorsqu'il est applique a trois types d'emballages differents, les resultats montrent des differences claires dans les deux criteres entre ces articles de conditionnement, ce est a dire des efficacites variables dans la protection du produit contenu et les doses delivrees, sachant que le premier aspect est d'une importance primordiale. Conclusion Le protocole propose est montre capable de discriminer entre les differents systemes d'emballage et fournit des informations sur les caracteristiques forts et faibles de certains types de technologies de distribution prevues a diminuer de facon efficace soit la contamination de la dose ou a prevenir la contamination qui pourrait atteindre le produit contenu. Par consequent, le protocole propose peut contribuer a une selection objective d'un PS pour proteger un produit de soin cosmetique avec une faible teneur d'agent de conservation ou exempt d'agent de conservation.

The effect of water soluble fat replacers and fat reduction on the growth of Lactobacillus sakei and Listeria monocytogenes in broth and pork liver paté

Abstract: The major objective of this study was to evaluate the effect of water soluble fat replacers on the growth of bacteria of importance to processed meats. The first part of the study evaluated the effect of water soluble fat replacers (Beneo™ GR, Beneo™ HPX, STA-LITE WSIII™, Fibersol-2 and Nutriose) on the growth of Lactobacillus sakei and Listeria monocytogenes . Fibersol-2 appears to have the greatest potential for replacing fat without compromising microbiological stability as increase in its water phase concentration resulted in a significant increase in the lag phases of both Lb. sakei and L. monocytogenes . On the other hand, Beneo™ GR stimulated the growth of L. monocytogenes , implying that its use could compromise microbiological safety. In the second part of the study pork liver pate and low fat pate (30% less fat) were challenged with L. monocytogenes . The low fat pate was determined to be microbiologically less stable than the reference pate. This was a result of the low fat pate having significantly higher water activity and pH values than those of the reference pate. The results of this study are of importance to the meat processing industry to make more informed decisions when reducing and/or replacing fat.