Fingerprint of lactic acid bacteria population in beef carpaccio is influenced by storage process and seasonal changes

We have investigated the population structure of lactic acid bacteria (LAB) for several beef carpaccio available on the market with the purpose of comparing the effect of storage process (modified-atmosphere packaging and vacuum-packaging) and of seasonal changes on this microbial population. Out of 60 samples we have characterised 214 isolates accounting for 10 LAB species and 35 isolates accounting for 11 non-LAB species. Lactobacillus sakei, Leuconostoc carnosum and Leuconostoc mesenteroides were the most prevailing LAB species with a frequency of identification within 66%, 62% and 52% of the samples respectively. These 3 species were also characterised by a phenotypic intra-species diversity of isolates based on colony morphology. We showed that the prevalence was increased 1.5 fold for L. sakei and L. mesenteroides during the summer sampling in comparison to the spring or the fall sampling suggesting an environmental origin of these two species. Seasonal variations were also observed for the prevalence of Lactobacillus fuchuensis and L. carnosum in spring (2- and 1.5-fold increase, respectively) and of Brochothrix thermosphacta in fall (6-fold increase). Finally, we demonstrated that the growth potential after the sell-by-date was favourable of 1.25 log₁₀ cfu g⁻¹ to Leuconostoc spp. in modified-atmosphere packaging and of 1.38 log₁₀ cfu g⁻¹ to Lactobacillus spp. in vacuum-packaging. In conclusion, we show that important and unsuspected traits in bacterial population dynamics can be unravelled by large sampling strategies. We discuss about the need to take this assessment into account for further studies on bacterial ecosystems of meat.     

Influence of temperature and relative humidity on the immobilized lactoperoxidase system in a functional chitosan film

The effect of temperature (10–30 °C), relative humidity (RH, 50–90%), and storage period (2–10 days) were studied on the production and sustainability of thiocyanate (SCN⁻) and hypothiocyanite–hypoiodite (OSCN⁻, OI⁻) components of a lactoperoxidase system (LPOSI) in chitosan film by applying response surface methodology and Doelhert experimental design. The results of analysis of variance indicated that the temperature and storage period exhibited a significant effect on the film properties. Temperature had a positive influence on OSCN⁻, OI⁻, while these products (OSCN⁻, OI⁻) decreased during the storage period, and SCN⁻ disappeared after 2 days. Lactoperoxidase systems with iodine (LPOSI) or without iodine (LPOS), incorporated into chitosan films, showed inhibition of Xanthomonas campestris pv. Mangiferae indicae and did not changed the chitosan film permeability to gas and water vapor.     

Effect of high pressure and salt on pork meat quality and microstructure

The interaction of salt (0%, 1.5%, and 3% in the final product) and a high-pressure treatment (500 MPa, 20 °C, 6 min) was investigated using pork biceps femoris muscle. The Warner-Bratzler shear force and the water holding capacity (WHC) were assessed and linked to the microstructure evaluation by environmental scanning electronic microscopy (ESEM). Pressure-treated and cooked samples showed a high Warner-Bratzler shear force with a low WHC compared to control cooked samples. These negative effects could be linked to the general shrinkage of the structure as observed by ESEM. The addition of 1.5% salt was sufficient to improve the technological properties of the high-pressure-treated samples and to counteract the negative effect of high pressure on texture and WHC. This phenomenon could be linked to the breakdown in structure observed by ESEM. This study states that it is possible to produce pressurized pork products of good eating quality by adding limited salt levels.     

Tocopherols in rose hips (Rosa spp.) during ripening

BACKGROUND: Rose hips are used as a food ingredient and in health products. They are rich in various bioactive compounds such as carotenoids and vitamin C, but data on their vitamin E content (tocopherols and tocotrienols) are limited. In this study, four different species ofRosa were analysed for tocopherol and tocotrienol content during ripening in three different years. RESULTS: Only α‐ and γ‐tocopherol were found in the fleshy parts of the rose hips, and the tocopherol content and vitamin E activity varied depending on date of harvesting, species and year. The amount of vitamin E activity differed between species of Rosa and years, whereas the changes during ripening were relatively small. CONCLUSION: The choice of species must be considered if tocopherol content is to be optimised when rose hips are used as a food ingredient. Copyright © 2012 Society of Chemical Industry     

Maple sap predominant microbial contaminants are correlated with the physicochemical and sensorial properties of maple syrup

Maple sap processing and microbial contamination are significant aspects that affect maple syrup quality. In this study, two sample sets from 2005 and 2008 were used to assess the maple syrup quality variation and its relationship to microbial populations, with respect to processing, production site and harvesting period. The abundance of maple sap predominant bacteria (Pseudomonas fluorescens group and two subgroups, Rahnella spp., Janthinobacterium spp., Leuconostoc mesenteroides) and yeast (Mrakia spp., Mrakiella spp.,Guehomyces pullulans) was assessed by quantitative PCR. Maple syrup properties were analyzed by physicochemical and sensorial methods. Results indicate that P. fluorescens, Mrakia spp., Mrakiella spp. G. pullulans and Rahnella spp. are stable contaminants of maple sap, as they were found for every production site throughout the flow period. Multiple factor analysis reports a link between the relative abundance of P. fluorescens group and Mrakia spp. in maple sap with maple and vanilla odor as well as flavor of maple syrup. This evidence supports the contribution of these microorganisms or a consortium of predominant microbial contaminants to the characteristic properties of maple syrup.     

Effect of production systems on phenolic composition and oxygen radical absorbance capacity of ‘Orléans’ strawberry

The effect of two production systems, plastic mulch (PM) and plastic mulch with row covers (PMRC) versus the commonly used matted-row system (MRS) was evaluated on phenolic composition and oxygen radical absorbance capacity (ORAC) of ‘Orléans’ strawberry at three different harvest times during growing season. Six major groups of phenolic compounds, including anthocyanins, hydroxycinnamic acids, kaempferol, flavonols, ellagic and benzoic acids, were assessed in strawberry. Production systems significantly affect the antioxidant capacity and phenolic content of strawberry. PMRC generally enhanced the phenolic content and total antioxidant capacity compared to MRS and PM, but the effects varied during the harvest season. Therefore, PMRC could be a recommended production system to improve the nutraceutical value of strawberry fruits especially in cooler climates.     

Herd-level and territorial-level factors influencing average herd somatic cell count in France in 2005 and 2006

Mastitis is a multifactorial disease and the most costly dairy production issue. In spite of extensive literature on udder-health risk factors, effects of metabolic diseases, farmers' competencies and livestock farming system on somatic cells count (SCC) are sparsely described. Herd-level or territorial-level factors affecting monthly composite milk weighted mean cow SCC (CMSCC) were analysed with a linear mixed effect model. The average CMSCC was 266,000 cells/ml. Half of the herds had CMSCC >300,000 cells/ml for 2-6 months a year, and 15% of herds for more than 7 months a year. CMSCC was positively associated with the number of cows, having a beef or fattening herd in addition to the dairy herd, the monthly average days in milk, the yearly age at first calving, the yearly proportion of purchased cows and the yearly culling rate. Moreover, a positive association is reported between CMSCC and the monthly proportion of cows probably with subacute ruminal acidosis (fat percentage minus protein percentage ≤0·30%, for Holstein) and negative energy balance (protein to fat ratio ≤0·66, for Holstein), the yearly average calving interval, having at least one dead cow and the mean monthly temperature. The association was negative for a predominant breed other than Holstein, the monthly milk production, the yearly dry-off period length, the monthly first calving cow proportion, having an autumn calving peak, being a Good Breeding Practices member, the monthly number of days with rain, the altitude and the territorial cattle density. CMSCC varied widely among the 11 dairy production areas. In conclusion, this study showed the average CMSCC for the French dairy cows, compared with international results. Moreover, it quantified the contribution of several factors to CMSCC, in particular metabolic diseases and the farm environment.     

Influence of temperature, pH and NaCl concentration on the maximal growth rate of Brochothrix thermosphacta and a bioprotective bacteria Lactococcus piscium CNCM I-4031

The maximum specific growth rate (μ_max) of Brochothrix thermosphacta, a spoilage bacteria of cooked peeled shrimp, and Lactococcus piscium CNCM I-4031, a bioprotective strain, was investigated under different conditions of temperature, NaCl concentrations and pH. The basic modelling approach used was the Gamma concept (γ-concept) and the model developed was then adapted to shrimp. Cardinal growth parameters were quite similar for the two strains, except for NaCl. No NaCl was required for growth and the NaCl_max was three-times higher for B. thermosphacta than for L. piscium (62 and 23 g l⁻¹ respectively). However, tolerance to NaCl was higher in seafood than in liquid broth, possibly due to presence of osmoltically active molecules. L. piscium and B. thermosphacta were psychrotolerant, with T_min = −4.8 and −3.4 °C, T_opt = 23.4 and 27.0 °C and T_max = 27.2 and 30.8 °C respectively. The optimal pH was neutral and growth possible till pH = 4.8 for the two strains, assuming possible applications of the bioprotective strain in lightly marinated seafood. The μ_max of B. thermosphacta in shrimp was a little higher than in L. piscium whatever the environmental conditions. Validation of the model showed that the γ-concept was suitable for predicting μ_max of B. thermosphacta in shrimp. Data generated in this study can be used to adapt the model to other foods with few additional experiments and the effect of different parameters may be added in the future. The model was less accurate for the bioprotective strain and the effect of NaCl must be studied in more detail directly in the matrix.     

A Shift Towards Landscape-Scale Approaches in Compensation - Suitable Mechanisms and Open Questions

ABSTRACT

Landscape-scale mitigation approaches reflect a shift from a project-by-project approach to more strategic planning by applying the mitigation hierarchy – avoidance, minimization, compensation – for impacts on natural resources on a larger scale. This paper discusses requirements for the implementation of landscape-scale mitigation approaches in general. It continues with a criteria-based analysis of compensation mechanism under the Endangered Species Act – conservation banks, in-lieu fees, and permittee-responsible mitigation – to determine which mechanism best meets these requirements. Findings show that, in theory, conservation banks are best-suited to implement landscape-scale compensation. However, evidence for claimed benefits of third-party mitigation and large-scale mitigation approaches is lacking. The article concludes by identifying a number of open questions in the field.     

Ecological compensation: an evaluation of regulatory compliance in New Zealand

Ecological compensation is an example of a trade-off whereby loss of natural values is remedied or offset by a corresponding compensatory action on the same site or elsewhere, determined through the process of Environmental Impact Assessment (EIA). Ecological compensation actions are often criticised for having low levels of compliance: meaning that they are achieved only partially or not at all, while development activity proceeds with much greater certainty. Our research investigated compliance with 245 conditions relating to ecological compensation across 81 case studies across New Zealand under the Resource Management Act 1991. Our results show that present tools and practice in New Zealand are not adequately securing the necessary benefits from ecological compensation requirements, with 35.2% of requirements not being achieved. Significant variation in non-compliance with ecological compensation occurs between different activities, applicant types and condition types, while critical variables within the planning process influence levels of compliance. Our research demonstrates the importance of understanding the nature of non-compliance and of providing a consistent and robust decision-making framework for the consideration of ecological compensation in practice.