Measuring the consumer benefits of improving farm animal welfare to inform welfare labelling

Policy makers in the European Union are envisioning the introduction of a community farm animal welfare label which would allow consumers to align their consumption habits with their farm animal welfare preferences. For welfare labelling to be viable the market for livestock products produced to higher welfare standards has to be sufficiently segmented with consumers having sufficiently distinct and behaviourally consistent preferences. The present study investigates consumers’ preferences for meat produced to different welfare standards using a hypothetical welfare score. Data is obtained from a contingent valuation study carried out in Britain. The ordered probit model was estimated using Bayesian inference to obtain mean willingness to pay. We find decreasing marginal WTP as animal welfare levels increase and that people’s preferences for different levels of farm animal welfare are sufficiently differentiated making the introduction of a labelling scheme in the form of a certified rating system appear feasible.

Effect of triclosan or a phenolic farm disinfectant on the selection of antibiotic-resistant Salmonella enterica

Objective: To determine the effect of growth of five strains of Salmonella enterica and their isogenic multiply antibiotic-resistant (MAR) derivatives with a phenolic farm disinfectant or triclosan (biocides) upon the frequency of mutation to resistance to antibiotics or cyclohexane. Methods: Strains were grown in broth with or without the biocides and then spread on to agar containing ampicillin, ciprofloxacin or tetracycline each at 4x MIC or agar overlaid with cyclohexane. Incubation was for 24 and 48 h and the frequency of mutation to resistance was calculated for strains with and without prior growth with the biocides. MICs were determined and the presence of mutations in the acrR and marR regions was determined by sequencing and the presence of mutations in gyrA by light-cycler analysis, for a selection of the mutants that arose. Results: The mean frequency of mutation to antibiotic or cyclohexane resistance was increased similar to10- to 100-fold by prior growth with the phenolic disinfectant or triclosan. The increases were statistically significant for all antibiotics and cyclohexane following exposure to the phenolic disinfectant (P less than or equal to 0.013), and for ampicillin and cyclohexane following exposure to triclosan (P less than or equal to 0.009). Mutants inhibited by >1 mg/L ciprofloxacin arose only from strains that were MAR. Reduced susceptibility to ciprofloxacin (at 4x MIC for parent strains) alone was associated with mutations in gyrA. MAR mutants did not contain mutations in the acrR or marR region. Conclusions: These data renew fears that the use of biocides may lead to an increased selective pressure towards antibiotic resistance.

Farm disinfectants select for cyclohexane resistance, a marker of multiple antibiotic resistance, in Escherichia coli

Aims: The aim of this study was to determine if three classes of farm disinfectants were able to select for ciprofloxacin or cyclohexane tolerant [ indicative of a multiple antibiotic resistance ( MAR) phenotype] Escherichia coli and if cyclohexane-tolerant E. coli could be isolated from farms. Methods and Results: Chicken slurry containing ca 1 : 99 ratio ciprofloxacin resistant : susceptible E. coli ( 10 different resistant strains examined) was treated for 24 h with each of the disinfectants and examined for survival of resistant : susceptible strains. Ciprofloxacin-sensitive ( n = 5) and - resistant ( n = 5) E. coli were grown with sublethal concentrations of the disinfectants and then plated to agar containing ciprofloxacin or overlaid with cyclohexane. Escherichia coli ( n = 389) isolated from farms were tested for cyclohexane tolerance. Minimum inhibitory concentrations ( MIC) were determined against representative isolates and mutants. The disinfectants did not select for the ciprofloxacin-resistant E. coli in poultry slurry but following growth with each of the three disinfectants, higher numbers ( Pless than or equal to 0(.)023) of cyclohexane-tolerant E. coli were isolated and these had a MAR phenotype. Of the 389 farm E. coli tested, only one was cyclohexane tolerant. Conclusions: It is possible that in a farm environment, E. coli could be exposed to similar concentrations of the disinfectants that are selected for MAR type organisms under these laboratory conditions. Significance and Impact of the Study: Data from this study suggest that cyclohexane-resistant E. coli are not common on farms, but in view of the ease of isolating them in the laboratory with farm disinfectants, further investigations on farms are warranted.

Commonly used farm disinfectants can select for mutant Salmonella enterica serovar Typhimurium with decreased susceptibility to biocides and antibiotics without compromising virulence

Objectives: To determine if one passage of Salmonella enterica serovar Typhimurium in the presence of farm disinfectants selected for mutants with decreased susceptibility to disinfectants and/or antibiotics. Methods: Eight Salmonella Typhimurium strains including field isolates and laboratory mutants were exposed to either a tar oil phenol (PFD) disinfectant, an oxidizing compound disinfectant (OXC), an aldehyde based disinfectant (ABD) or a dairy sterilizer disinfectant (based on quaternary ammonium biocide) in agar. The susceptibility of mutants obtained after disinfectant exposure to antibiotics and disinfectants was determined as was the accumulation of norfloxacin. The proteome of SL1344 after exposure to PFD and OXC was analysed using two-dimensional liquid chromatography mass spectrometry. Results: Strains with either acrB or tolC inactivated were more susceptible to most disinfectants than other strains. The majority (3/5) of mutants recovered after disinfectant exposure required statistically significantly longer exposure times to disinfectants than their parent strains to generate a 5 log kill. Small decreases in antibiotic susceptibility were observed but no mutants were multiply antibiotic-resistant (MAR). Notably exposure to ABD decreased susceptibility to ciprofloxacin in some strains. Mutants with increased disinfectant tolerance were able to survive and persist in chicks as well as in parent strains. Analysis of proteomes revealed significantly increased expression of the AcrAB-TolC efflux system after PFD exposure. Conclusions: Data presented demonstrate that efflux pumps are required for intrinsic resistance to some disinfectants and that exposure to disinfectants can induce expression of the AcrAB-TolC efflux system, but that single exposure was insufficient to select for MAR strains.

Where theory meets practice: a critical comparison of research into identifying letters and craft knowledge of type design

This paper introduces scientific research findings and accounts of skilled design judgement to: (i) develop an interdisciplinary account of what affects our identification of letters when reading; (ii) analyse the relationship between the approaches of psychologists and designers to explaining how we identify letters; (iii) propose ways in which collaboration may work to make psychological research more relevant to typographic practice. The topics reviewed are addressed within each discipline and cover the contribution of letters and words to reading; letter features; essential or structural forms; uniformity within font design; and letter spacing. Analysis of the literature identifies possible means of reconciling different perspectives, points out some anomalies in interpretation of findings, and proposes how designers may contribute to research planning and dissemination.