Bottle or tap? Toward an integrated approach to water type consumption.

While in many countries, people have access to cheap and safe potable tap water, the global consumption of bottled water is rising. Flanders, Belgium, where this study is located, has an exceptionally high consumption of bottled water per capita. However, in the interest of resource efficiency and global environmental challenges, the consumption of tap water is preferable. To our knowledge, an integrated analysis of the main reasons why people consume tap and bottled water is absent in Flanders, Belgium. Using Flemish survey data (N = 2309), we first compared tap and bottled water consumers through bivariate correlation analysis. Subsequently, path modelling techniques were used to further investigate these correlations. Our results show that bottled water consumption in Flanders is widespread despite environmental and financial considerations. For a large part, this is caused by negative perceptions about tap water. Many consumers consider it unhealthy, unsafe and prefer the taste of bottled water. Furthermore, we found that the broader social context often inhibits the consumption of tap water. On the one hand, improper infrastructures (e.g. lead piping) can limit access to potable tap water. On the other hand, social norms exist that promote bottled water. Lastly, results suggest that the consumption of bottled water is most common among men, older people and less educated groups. We conclude that future research and policy measures will benefit from an approach that integrates all behavioural aspects associated with water type consumption. This will enable both governments and tap water companies to devise more effective policies to manage and support tap water supply networks.

Economics of reducing Campylobacter at different levels within the Belgian poultry meat chain.

Campylobacter infections pose a serious public health problem in Belgium. Poultry meat is most likely responsible for 40% of human campylobacteriosis cases in Belgium. On a yearly basis, consumption of poultry meat causes at least 22,000 campylobacteriosis cases, with a cost of illness of Euro 10.9 million. Several intervention measures have been proposed in literature, aiming to reduce the contamination of poultry meat and thus lead to significant reductions of human campylobacteriosis cases. This study aimed to evaluate the cost-benefit ratio, i.e., the ratio of reduced costs of illness on intervention costs of various intervention measures. These measures were selected by representatives from the poultry meat sector and experts in the field of poultry science. The selection comprised measures at the farm level (phage therapy), at the processing plant (spraying of carcasses with lactic acid or electrolyzed oxidizing water, crust freezing, or irradiation), and at the consumer level (improving kitchen hygiene and application of home freezing). Among these measures, the decontamination of carcasses with electrolyzed oxidizing water applied in the processing plant was the most efficient (17.66), followed by the use of lactic acid (4.06). In addition, phage therapy generated a positive cost-benefit ratio (2.54). Irradiation indicated the highest efficacy, but its cost-benefit ratio was rather low (0.31). There seems to be less gain by trying to improve food handling in the kitchen. The cost to reach consumers is large, while only a very limited fraction of the consumers is willing to change its behavior. The outcome of this study poses valuable information for future risk-management decisions in Belgium.

Poly-beta-hydroxybutyrate-accumulating bacteria protect gnotobiotic Artemia franciscana from pathogenic Vibrio campbellii.

A poly-beta-hydroxybutyrate (PHB)-accumulating enrichment culture was obtained using activated sludge from a polyphosphate-accumulating reactor as inoculum. PHB accumulated by the enrichment culture significantly enhanced the survival of Artemia nauplii, infected with the virulent pathogen Vibrio campbellii LMG 21363. A strain was isolated from the enrichment culture, based on its ability to accumulate PHB, and 16S rRNA gene sequencing of the isolate revealed 99% sequence similarity to Brachymonas denitrificans AS-P1. The isolate, named PHB2, showed good PHB-accumulating activity (up to 32% of the cell dry weight). PHB accumulated by isolate PHB2 was able to protect Artemia completely from the V. campbellii strain. Our data indicate that PHB-accumulating bacteria, such as B. denitrificans PHB2, could be used as an an effective and economically interesting alternative strategy to control infections in aquaculture.

Community dynamics of methanotrophic bacteria during composting of organic matter.

In this study, we describe the effects of composting on the diversity, abundance and activity of the methanotrophic community present in the compost. Composting was allowed to proceed for 10 weeks in an in-vessel reactor. Self-heating capacity (Rottegrad) indicated that compost maturity was reached after 4 weeks. After 6 weeks, a second thermophilic phase was induced by manually increasing temperature to investigate whether or not the methanotrophs shifted back to the thermophilic population. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) with primers specific for type I methanotrophs of 16S rDNA and 16S rRNA were used to characterize the composition of the microbial community. Cluster and diversity analyses of RNA DGGE patterns were more sensitive than those of DNA DGGE patterns, and revealed that mesophilic and thermophilic methanotrophic communities could be differentiated. Moreover, it was seen that the diversity of the community was low during the thermophilic phase and increased during the final maturation phase. Real-time PCR analysis was also performed on the DNA and RNA extracts and showed no changes in the abundance of type I methanotrophs during the composting process (10(9) DNA copies/g compost). However, RNA-related activity did change, with the lowest activity (10(7) cDNA copies/g compost) observed during the thermophilic phase, subsequently increasing to its maximum value (10(9) cDNA copies/g compost), and finally decreasing during the maturation phase. This study confirmed the population dynamics, as seen for general groups such as bacteria and fungi during composting, for a very specific and sensitive group of bacteria, it is the type I methanotrophs.

The bacterial storage compound poly-beta-hydroxybutyrate protects Artemia franciscana from pathogenic Vibrio campbellii.

Infections caused by antibiotic-resistant luminescent Vibrios can cause dramatic losses in aquaculture. In this study, the short-chain fatty acid beta-hydroxybutyrate and its polymer poly-beta-hydroxybutyrate were investigated as possible new biocontrol agents. beta-Hydroxybutyrate was shown to completely inhibit the growth of pathogenic Vibrio campbelli at 100 mM. Moreover, the addition of 100 mM of this fatty acid to the culture water of Artemia nauplii infected with the V. campbelli strain significantly increased the survival of the nauplii. As Artemia is a non-selective and particle filter feeder, we also investigated whether poly-beta-hydroxybutyrate particles could be used to protect Artemia from the pathogenic V. campbellii. The addition of 100 mg l(-1) poly-beta-hydroxybutyrate or more to the Artemia culture water offered a preventive and curative protection from the pathogen as a significantly enhanced survival was noticed. If added as a preventive treatment, a complete protection of infected nauplii (no significant mortality compared with uninfected nauplii) was observed at 1000 mg l(-1) poly-beta-hydroxybutyrate. Our data indicate that the use of poly-beta-hydroxybutyrate might constitute an ecologically and economically sustainable alternative strategy to fight infections in aquaculture.