Predation of brown tree snakes (Boiga irregularis) in Australia

We conducted a literature review to address the potential for using a native, vertebrate predator of brown tree snakes (Boiga irregularis) as a biological control method on Guam. Both actual and potential predators were included in our review. We located two actual predators (red-bellied black snakes (Pseudechis porphyriacus) and cane toads (Bufo marinus)) and 55 potential predators of brown tree snakes. However, none of the native predators of brown tree snakes appear likely candidates as a biological control method on Guam due to their lack of selectivity in their feeding habits and unknown aspects of their natural history. (C) 2002 Elsevier Science Ltd. All rights reserved.

Alternative technologies for producing sterile low acid food products

Four emerging high-energy non-thermal technologies may replace or augment heating for producing sterile low-acid food products. High pressure, high-voltage pulsed electric field, high-energy ultrasound and high-intensity pulsed light are all capable of reducing bacterial spore counts under certain conditions. However, only non-continuous high pressure treatments, at temperatures higher than ambient, are currently capable of completely inactivating spores and producing sterile food products. The first three technologies also reduce the resistance of spores to inactivation by heat.

Food safety and development of the beef industry in China

Food safety concerns have escalated in China as they have elsewhere, especially in relation to meats. Beef production and consumption has increased proportionately faster than all other meats over the last two decades. Yet the slaughtering, processing and marketing of beef remains, for the most part, extremely primitive when compared with Western beef supply chains. By comparing the economics of household slaughtering with that of various types of abattoirs, this paper explains why household slaughtering and wet markets still dominate beef processing and distribution in China. The negative economic, social and industry development implications of enforcing more stringent food safety regulations are highlighted. The willingness/capacity of consumers to pay the added cost of better inspection and other services to guarantee food safety is investigated. In this context, the paper also evaluates the market opportunities for both domestic and imported Green Beef. The paper questions the merit of policy initiatives aimed at modernising Chinese beef supply chains for the mass market along Western lines. (C) 2002 Elsevier Science Ltd. All rights reserved.

Food Cent$: Educating mothers with a mental illness about nutrition

People with a mental illness can have deficits in a range of areas, including food skills. Mothers who have a mental illness and have residential care of their children are particularly vulnerable to experiencing food insecurity. The food skills programme known as Food Cent$ is a new way of spending money on food using the 10-plan, so that people can learn to balance their diet and their food budget. Occupational therapists in a mental health rehabilitation service incorporated the use of Food Cent$ into a parenting programme for mothers with a mental illness. A pilot study was conducted to identify whether the Food Cent$ programme influenced behaviours and attitudes towards food and food selection and preparation and reduced grocery expenditure. The participants were six mothers with a mental illness who had children under 5 years of age in their care. A focus group was conducted to gain insight into the experiences of mothers who had attended the programme. Supermarket receipts were collected before and after the project to determine changes in dietary practices. The results indicated that attending Food Cent$ contributed to an improvement in dietary intake, food selection and preparation, and grocery expenditure. Further research is required into the effectiveness of this programme with other target groups likely to experience food insecurity.

Trichostome ciliates from Australian marsupials. III. Megavestibulum gen. nov. (Litostomatea : Macropodiniidae)

A new macropodiniid ciliate genus, Megavestibulum, is described which is endocommensal in the stomach of macropodid marsupials. Two new species, M. morganorum and M. kuhri, are described from Macropus dorsalis and Wallabia, bicolor respectively. Megavestibulum is holotrichous, the somatic ciliation arranged into meridional, curving kineties between broad ridges. The interkinetal ridges are lined apically by thick-walled vacuoles similar to those lining the longitudinal grooves of Macropodinium. The conical vestibulum is apical and very large, occupying up to 1/3 of the cell volume. The vestibular lip appears closable and has a cleft which may allow distention of the vestibullum to ingest large food items. The vestibular ultrastructure is similar to that of Macropodinium including the presence of vestibular vacuoles and the hemispherical differentiation of the distribution of small nematodesmata. Many specimens contained ingested whole ciliates of the genera Amylovorax and Polycosta. The structure of the vestibulum suggests that Megavestibulum is adapted for life as an active predator of other stomach ciliates as well as sweeping in small particulates. The morphology of Megavestibulum suggests that it represents the plesiomorphic body plan within the family Macropodiniidae.

The use of 16s rDNA restriction fragment length polymorphism analysis for the identification of non-fermenting gram negative bacilli in a cystic fibrosis microbiology referral service

The utility of 16s rDNA restriction fragment length polymorphism (RFLP) analysis for the partial genomovar differentiation of Burkholderia cepacia complex bacterium is well documented. We compared the 16s rDNA RFLP signatures for a number of non-fermenting gram negative bacilli (NF GNB) LMG control strains and clinical isolates pertaining to the genera Burkholderia, Pseudomonas, Achromobacter (Alcaligenes), Ralstonia, Stenotrophomonas and Pandoraea. A collection of 24 control strain (LMG) and 25 clinical isolates were included in the study. Using conventional PCR, a 1.2 kbp 16s rDNA fragment was generated for each organism. Following restriction digestion and electrophoresis, each clinical isolate RFLP signature was compared to those of the control strain panel. Nineteen different RFLP signatures were detected from the 28 control strains included in the study. TwentyoneyTwenty- five of the clinical isolates could be classified by RFLP analysis into a single genus and species when compared to the patterns produced by the control strain panel. Four clinical B. pseudomallei isolates produced RFLP signatures which were indistinguishable from B. cepacia genomovars I, III and VIII. The identity of these four isolates were confirmed using B. pseudomallei specific PCR. 16s rDNA RFLP analysis can be a useful identification strategy when applied to NF GNB, particularly for those which exhibit colistin sulfate resistance. The use of this molecular based methodology has proved very useful in the setting of a CF referral laboratory particularly when utilised in conjunction with B. cepacia complex and genomovar specific PCR techniques. Species specific PCR or sequence analysis should be considered for selected isolates; especially where discrepancies between epidemiology, phenotypic and genotypic characteristics occur.

Heat resistance of Bacillus spores when adhered to stainless steel and its relationship to spore hydrophobicity

Twenty-one strains of Bacillus (10 B. stearothermophilus, 3 B. cereus, and 8 B. licheniformis strains) were assayed for spore surface hydrophobicity on the basis of three measures: contact angle measurement (CAM), microbial adhesion to hydrocarbons (MATH), and hydrophobic interaction chromatography (HIC). On the basis of the spore surface characteristics obtained from these assays, along with data on the heat resistance of these spores in water, eight strains of Bacillus (three B. stearothermophilus, three B. cereus, and two B. licheniformis strains) either suspended in water or adhering to stainless steel were exposed to sublethal heat treatments at 90 to 110degreesC to determine heat resistance (D-value). Significant increases in heat resistance (ranging from 3 to 400%) were observed for the eight strains adhering to stainless steel. No significant correlation was found between these heat resistance increases and spore surface characteristics as determined by the three hydrophobicity assays. There was a significant positive correlation between the hydrophobicity data obtained by the MATH assay and those obtained by the HIC assay, but these data did not correlate with those obtained by the CAM assay.

Combining nonthermal technologies to control foodborne microorganisms

Novel nonthermal processes, such as high hydrostatic pressure (HHP), pulsed electric fields (PEFs), ionizing radiation and ultrasonication, are able to inactivate microorganisms at ambient or sublethal temperatures. Many of these processes require very high treatment intensities, however, to achieve adequate microbial destruction in low-acid foods. Combining nonthermal processes with conventional preservation methods enhances their antimicrobial effect so that lower process intensities can be used. Combining two or more nonthermal processes can also enhance microbial inactivation and allow the use of lower individual treatment intensities. For conventional preservation treatments, optimal microbial control is achieved through the hurdle concept, with synergistic effects resulting from different components of the microbial cell being targeted simultaneously. The mechanisms of inactivation by nonthermal processes are still unclear; thus, the bases of synergistic combinations remain speculative. This paper reviews literature on the antimicrobial efficiencies of nonthermal processes combined with conventional and novel nonthermal technologies. Where possible, the proposed mechanisms of synergy is mentioned. (C) 2003 Elsevier Science B.V. All rights reserved.

An SNP-based PCR assay to differentiate between Listeria monocytogenes lineages derived from phylogenetic analysis of the sigB gene

The alternative sigma factor sigB gene is involved in the stress response regulation of Listeria monocytogenes, and contributes towards growth and survival in adverse conditions. This gene was examined to determine if it could be a useful indicator of lineage differentiation, similar to the established method based on ribotyping. The sigB sequence was resolved in four local L. monocytogenes strains and the phylogenetic relationship among these, and a further 21 sigB gene sequences from strains of different serotype and lineage including two Listeria innocua strains, obtained from the GenBank database were determined. The sigB nucleotide sequences of these 25 Listeria strains were then examined for single nucleotide polymorphic (SNP) sites that could differentiate between the three lineages. Based on nucleotide sequences L. monocytogenes lineage F serotype 1/2b and 4b clustered together, lineage II/serotype 1/2a and 1/2c strains clustered together, lineage III/serotypes 4a and 4c strains clustered together and L. innocua strains clustered together as an outgroup. SNPs differentiating the three lineages were identified. Individual allele-specific PCR reactions based on these polymorphisms were successful in grouping known and a further 37 local L. monocytogenes isolates into the three lineages. (C) 2003 Elsevier B.V. All fights reserved.

Quantification of Listeria spp. contamination on shell and flesh of cooked black tiger prawns (Penaeus monodon)

Aims: To quantify Listeria levels on the shell and flesh of artificially contaminated cooked prawns after peeling, and determine the efficacy of Listeria innocua as a model for L. monocytogenes in this system. Methods and Results: A L. monocytogenes and L. innocua strain were inoculated separately onto cooked black tiger prawns using two protocols ( immersion or swabbing with incubation). Prawns were peeled by two methods ( gloved hand or scalpel and forceps) and numbers of Listeria on shells, flesh and whole prawn controls were determined. Prawns were exposed to crystal violet dye to assess the penetration of liquids. Regardless of preparation method or bacterial strain there were ca 1log(10) CFU more Listeria per shell than per peeled prawn. Dye was able to penetrate to the flesh in all cases. Conclusions: Shell-on prawns may be only slightly safer than shell-off prawns. Listeria innocua is an acceptable model for L. monocytogenes in this system. Significance and Impact of the Study: Reduced risk from L. monocytogenes on prawns can only be assured by adequate hygiene or heating.