title: Psychrophilic and psychrotrophic Clostridium spp. associated with meat spoilage

authors: Broda, Dorota Maria

abstract: Twenty two isolates of psychrophilic and psychrotrophic Clostridium spp. associated with ‘blown pack’ spoilage of vacuum-packed meats were studied with respect to their identification, differentiation and taxonomy, as well as spoilage aetiology. The aetiological study was conducted to establish whether a causal relationship exists between psychrophilic and psychrotrophic clostridia and the production of abundant gas in vacuum-packed chilled meats. The attempt was then made to identify these clostridia using conventional microbiological methods. Genotypic approaches to differentiation of psychrophilic and psychrotrophic clostridia at inter- and intra-species level were evaluated and applied to tracing the ‘blown pack’ spoilage causing clostridia back to their contamination source in the abattoir. Where phenotypic and genotypic characteristics indicated that some isolates of psychrophilic and psychrotrophic clostridia differed from those previously described, taxonomic studies were conducted to determine whether these isolates could be described as new clostridial species. Four clostridial isolates were found to cause premature vacuum pack distension during chilled storage. Conventional phenotype based methods were found to be ineffective for identification of psychrophilic and psychrotrophic clostridia. Although RFLP analysis of the amplified 16S rDNA gene allowed differentiation of psychrophilic and psychrotrophic clostridia at the genotypic species level and below, comparison of PCR-RFLP patterns and 16S rDNA sequences of meat isolates with patterns and sequences of reference strains did not effect ready identification of some of these microorganisms. Consequently, the use of these methods for identification of unknown clostridial isolates needs to be approached carefully. Differentiation of some meat-derived isolates of psychrophilic and psychrotrophic clostridia at intra-species or inter-strain level was achieved with methods based on polymorphism of genomic DNAs and/or the 16S-23S rDNA internal transcribed spacers from these organisms. With the 16S-23S rDNA internal transcribed spacer polymorphism analysis, inter-species differentiation of psychrophilic and psychrotrophic clostridia may be achieved in instances where little inter-strain variation is expected e.g. in typing of isolates from the same meat plant or spoilage incident. Hides and faeces of slaughter animals were identified as an abundant abattoir source of psychrophilic and psychrotrophic clostridia representing many species. Seven isolates of these microorganisms, representing four distinct taxonomic groups, were found to differ in their phenotypic, genotypic and phylogenetic characteristics from known clostridial species. With a polyphasic approach, three new clostridial species, C. frigidicarnis, C. gasigenes and C. algidixylanolyticum have been named and characterised. It is hoped that this study has added to our understanding of the aetiology and causative agents of ‘blown pack’ spoilage and, thus, has advanced the process of developing measures to control this type of spoilage of vacuum packed chilled meats.

text: Psychrophilic and psychrotrophic Clostridium spp. associated with meat spoilage Twenty two isolates of psychrophilic and psychrotrophic Clostridium spp. associated with ‘blown pack’ spoilage of vacuum-packed meats were studied with respect to their identification, differentiation and taxonomy, as well as spoilage aetiology. The aetiological study was conducted to establish whether a causal relationship exists between psychrophilic and psychrotrophic clostridia and the production of abundant gas in vacuum-packed chilled meats. The attempt was then made to identify these clostridia using conventional microbiological methods. Genotypic approaches to differentiation of psychrophilic and psychrotrophic clostridia at inter- and intra-species level were evaluated and applied to tracing the ‘blown pack’ spoilage causing clostridia back to their contamination source in the abattoir. Where phenotypic and genotypic characteristics indicated that some isolates of psychrophilic and psychrotrophic clostridia differed from those previously described, taxonomic studies were conducted to determine whether these isolates could be described as new clostridial species. Four clostridial isolates were found to cause premature vacuum pack distension during chilled storage. Conventional phenotype based methods were found to be ineffective for identification of psychrophilic and psychrotrophic clostridia. Although RFLP analysis of the amplified 16S rDNA gene allowed differentiation of psychrophilic and psychrotrophic clostridia at the genotypic species level and below, comparison of PCR-RFLP patterns and 16S rDNA sequences of meat isolates with patterns and sequences of reference strains did not effect ready identification of some of these microorganisms. Consequently, the use of these methods for identification of unknown clostridial isolates needs to be approached carefully. Differentiation of some meat-derived isolates of psychrophilic and psychrotrophic clostridia at intra-species or inter-strain level was achieved with methods based on polymorphism of genomic DNAs and/or the 16S-23S rDNA internal transcribed spacers from these organisms. With the 16S-23S rDNA internal transcribed spacer polymorphism analysis, inter-species differentiation of psychrophilic and psychrotrophic clostridia may be achieved in instances where little inter-strain variation is expected e.g. in typing of isolates from the same meat plant or spoilage incident. Hides and faeces of slaughter animals were identified as an abundant abattoir source of psychrophilic and psychrotrophic clostridia representing many species. Seven isolates of these microorganisms, representing four distinct taxonomic groups, were found to differ in their phenotypic, genotypic and phylogenetic characteristics from known clostridial species. With a polyphasic approach, three new clostridial species, C. frigidicarnis, C. gasigenes and C. algidixylanolyticum have been named and characterised. It is hoped that this study has added to our understanding of the aetiology and causative agents of ‘blown pack’ spoilage and, thus, has advanced the process of developing measures to control this type of spoilage of vacuum packed chilled meats.

year: 1999

title: Psychological Climate, Work Engagement, Intention to Leave and Organisational Citizenship Behaviour in Small Hospitality Businesses.

authors: Strydom, Ance

subjects: work engagement

abstract: The aim of the current study was to examine the interrelations of important work related variables within small New Zealand based hospitality organisations in order to enhance the understanding of factors that contribute to success within these organisations. Of particular interest was the role of employee work environment perceptions (psychological climate) in relation to employee work engagement, intention to leave and organisational citizenship behaviour directed at the organisation (OCBO). Two theoretical models were tested to investigate the expected role of psychological climate. Model 1 was a mediation model wherein work engagement was expected to mediate between psychological climate, and intention to leave and OCBO. Model 2 took an alternative approach in which psychological climate was posed as a moderator of predicted work engagement-intention to leave and intention to leave-OCBO relationships. 
In total, 177 surveys were included in the data analyses. The results provided full support for Model 1, showing significant relationships between all psychological climate dimensions and work engagement. Work engagement in turn was negatively related to intention to leave and positively related to OCBO. Work engagement mediated the relationships between the psychological climate dimensions and intention to leave and OCBO. Little support was found, however, for Model 2. Although, as predicted, there were negative relationships between work engagement and intention to leave, and intention to leave and OCBO, intention to leave was not found to mediate between work engagement and OCBO. More importantly, no moderation effects were observed for the psychological climate dimensions. 
No causal inferences may be drawn from the results of this study. Nevertheless, the findings do suggest that psychological climate has an important role to play in determining levels of work engagement, which in turn impacts on employee intentions to leave their jobs and to voluntarily demonstrate behaviours that can enhance organisational effectiveness. Additionally, the negative correlations between intention to leave and OCBO indicate that employees who are seriously entertaining the idea of exiting the organisation may reduce their levels of OCBO.
 
It is suggested that owner/managers of small hospitality organisations actively focus on modifying aspects of the work environment that are likely to promote favourable work environment perceptions and positively shape employees work-related affective-cognitive state.

text: Psychological Climate, Work Engagement, Intention to Leave and Organisational Citizenship Behaviour in Small Hospitality Businesses. The aim of the current study was to examine the interrelations of important work related variables within small New Zealand based hospitality organisations in order to enhance the understanding of factors that contribute to success within these organisations. Of particular interest was the role of employee work environment perceptions (psychological climate) in relation to employee work engagement, intention to leave and organisational citizenship behaviour directed at the organisation (OCBO). Two theoretical models were tested to investigate the expected role of psychological climate. Model 1 was a mediation model wherein work engagement was expected to mediate between psychological climate, and intention to leave and OCBO. Model 2 took an alternative approach in which psychological climate was posed as a moderator of predicted work engagement-intention to leave and intention to leave-OCBO relationships. 
In total, 177 surveys were included in the data analyses. The results provided full support for Model 1, showing significant relationships between all psychological climate dimensions and work engagement. Work engagement in turn was negatively related to intention to leave and positively related to OCBO. Work engagement mediated the relationships between the psychological climate dimensions and intention to leave and OCBO. Little support was found, however, for Model 2. Although, as predicted, there were negative relationships between work engagement and intention to leave, and intention to leave and OCBO, intention to leave was not found to mediate between work engagement and OCBO. More importantly, no moderation effects were observed for the psychological climate dimensions. 
No causal inferences may be drawn from the results of this study. Nevertheless, the findings do suggest that psychological climate has an important role to play in determining levels of work engagement, which in turn impacts on employee intentions to leave their jobs and to voluntarily demonstrate behaviours that can enhance organisational effectiveness. Additionally, the negative correlations between intention to leave and OCBO indicate that employees who are seriously entertaining the idea of exiting the organisation may reduce their levels of OCBO.
 
It is suggested that owner/managers of small hospitality organisations actively focus on modifying aspects of the work environment that are likely to promote favourable work environment perceptions and positively shape employees work-related affective-cognitive state.

year: 2014

title: Spot sampling of nutrient concentrations in the Puarenga catchment, Rotorua

authors: Abell, Jonathan Michael

subjects: New Zealand

abstract: The Centre for Biodiversity and Ecology Research was approached by Tūhourangi Tribal Authority for assistance with measuring water quality in streams in the Puarenga Stream catchment. Water sampling was subsequently undertaken on 18 July 2011 and samples were analysed to determine concentrations of total and dissolved fractions of nitrogen and phosphorus. 
Nitrogen and phosphorus are both essential plant nutrients which, when present in excess, can cause eutrophication and associated water quality decline of freshwaters. High concentrations of dissolved forms of nitrogen can also be toxic to aquatic organisms. Excessive nitrogen and phosphorus concentrations are typically the result of pollution due to human activities, although groundwater in the Central Volcanic Plateau region can have elevated concentrations of phosphorus arising from natural geological sources.
This report summarises the methods used, presents the results and places measured concentrations in context by drawing comparisons with both guideline and regional mean values.

text: Spot sampling of nutrient concentrations in the Puarenga catchment, Rotorua The Centre for Biodiversity and Ecology Research was approached by Tūhourangi Tribal Authority for assistance with measuring water quality in streams in the Puarenga Stream catchment. Water sampling was subsequently undertaken on 18 July 2011 and samples were analysed to determine concentrations of total and dissolved fractions of nitrogen and phosphorus. 
Nitrogen and phosphorus are both essential plant nutrients which, when present in excess, can cause eutrophication and associated water quality decline of freshwaters. High concentrations of dissolved forms of nitrogen can also be toxic to aquatic organisms. Excessive nitrogen and phosphorus concentrations are typically the result of pollution due to human activities, although groundwater in the Central Volcanic Plateau region can have elevated concentrations of phosphorus arising from natural geological sources.
This report summarises the methods used, presents the results and places measured concentrations in context by drawing comparisons with both guideline and regional mean values.

year: 2011-09