Philip Button | University of Melbourne (original) (raw)

Papers by Philip Button

Annals of the Royal College of Surgeons of England, 1994

Acis 2013 Proceedings of the 24th Australasian Conference on Information Systems, 2013

ABSTRACT Consumers receive food-related information from various sources and strive to make infor... more ABSTRACT Consumers receive food-related information from various sources and strive to make informed food choices regarding their health, lifestyle and belief. To be effective and reliable, the information consumers receive needs to be from a credible source and delivered to them in a way they trust. The aim of this study was to investigate the sources and media channels of that information consumer trust. An online and hardcopy survey of 298 consumers currently living in Australia was carried out. Many consumers believe that the source of food product information is important (87%). As a source of general and nutritional information, Health Professionals, Scientists and Government sources are the most trusted sources, with at least 80% of participants confident of the information coming from these sources. Retailer advertising and social media are the least trusted sources with just 29% and 11%, respectively, confident of these sources. As a delivery medium, printed food labels (67%) and printed brochures or fact sheets (56%) remain the most trusted delivery media compared with electronic media, such as mobile phone or the Internet.

Consumers receive food-related information from various sources and strive to make informed food ... more Consumers receive food-related information from various sources and strive to make informed food choices regarding their health, lifestyle and belief. To be effective and reliable, the information consumers receive needs to be from a credible source and delivered to them in a way they trust. The aim of this study was to investigate the sources and media channels of that information consumer trust. An online and hardcopy survey of 298 consumers currently living in Australia was carried out. Many consumers believe that the source of food product information is important (87%). As a source of general and nutritional information, Health Professionals, Scientists and Government sources are the most trusted sources, with at least 80% of participants confident of the information coming from these sources. Retailer advertising and social media are the least trusted sources with just 29% and 11%, respectively, confident of these sources. As a delivery medium, printed food labels (67%) and pr...

Consumers are looking for more product information, but what information are they looking for? An... more Consumers are looking for more product information, but what information are they looking for? And in this connected world, who do they trust to deliver the information? Information about food products covers mandatory nutritional information, the ingredients list, health and nutrient claims, and a range of other information. This includes information concerning organic production certification, status of the inclusion of genetically modified (GM) ingredients or the environmental impact of manufacturing of the food product. This information is widely available from a variety of sources, including mass media, farmers, growers, manufacturers, retailers,public authorities, consumer organisations, scientists and health professionals. Consumers are often exposed to this plethora of information, which can sometimes be contradictory and confusing. This report provides insights into: What information do consumers look for? Who do consumers trust to provide the information? and What medium d...

FoodLegal Bulletin, Apr 3, 2014

In an effort to draw attention to the subject of structure/function relationships in high-solid b... more In an effort to draw attention to the subject of structure/function relationships in high-solid biopolymer mixtures, this investigation produces binary composites of agarose with gelatin and systematically increases the amount of glucose syrup, which is the co-solute in this system. Experimental work was carried out using small-deformation dynamic oscillation on shear and modulated differential scanning calorimetry. Agarose/gelatin mixtures in an aqueous low-solid environment form non-interactive bicontinuous networks. Addition of glucose syrup to the polymeric blend prevents the formation of stable double helices in the environment. Gelatin, on the other hand, better withstands the co-solute-induced change in solvent quality. At subzero temperatures, materials go through the rubber-to-glass transition whose DSC glass transition temperature (Tg) is governed by the total level of solids in the system. Estimation of the mechanical Tg acquires physical significance by utilising the theory of free volume, as modelled by the Williams, Landel and Ferry (WLF) equation. The single value of Tg estimated by this approach argues in accordance with experimental observations for the predominance of the gelatin network in the high-solid mixture.

During growth in raw milk, many psychrotrophic bacteria produce proteases that can retain activit... more During growth in raw milk, many psychrotrophic bacteria produce proteases that can retain activity following ultra-high temperature (UHT) treatment. In this study, casein and skim milk powder assays for detecting very low levels of protease in UHT milk were optimized, and the suitability of azocasein and fluorescein isothiocyanate-casein (FITC-casein) as substrates was investigated. The strongest correlations of protease activity with proteolysis in stored UHT milk were observed when FITC-casein was used as substrate in the assays.Assays using casein and FITC-casein as substrates yielded the highest activities.To determine sensitivity, crude protease was added at low concentrations to UHT milk, and the milk was assayed for progress of proteolysis over 12 months and for protease activity using the casein and FITC-casein assays. With long assay incubation times, the FITC-casein assay was more sensitive than the casein assay and may be suitable for detecting very low levels of protease activity and predicting progress of proteolysis in stored UHTwhole milk.

Book chapters by Philip Button

99 & Counting Medical Myths Debunked, 2013

Raw Milk: Production, Consumption and Health Effects, 2012

"Many types of microorganisms are present in the milk collection environment and diversity in the... more "Many types of microorganisms are present in the milk collection environment and diversity in the raw milk microflora is typical, without dominance of a single species. The proportion of psychrotrophic bacteria in raw milk can vary widely and is associated with the level of farm hygiene. Studies in Europe have shown that typically, no more than 10% of the flora of good quality milk will be psychrotrophic with Pseudomonas species comprising a substantial proportion of these. Pseudomonas fluorescens, the most common species of the genus present in raw milk, has been involved in bacterial spikes (sudden elevations in total bacterial count) in farm bulk tank milk. Psychrotrophic Pseudomonas species play an important role in spoilage of UHT milk through the production of heat-stable lipases and proteases in raw milk that retain activity following UHT processing. Lipase and protease, produced by psychrotrophic Pseudomonas species are detected when the cell count exceeds ~106 cfu/mL. Prolonged refrigerated (4 ºC) storage of raw milk increases the proportion of Pseudomonas species as do slightly higher temperatures (for example 6 ºC) over a shorter period of time. This in turn increases the likelihood that they will produce heat-stable lipases and proteases. Furthermore, temperature fluctuations have been shown historically to occur in farm bulk milk, and the temperature of raw milk at the time of collection can vary widely. While less likely to occur today, both these scenarios could further compound the problem of Pseudomonas species proliferation in raw milk.

The aim of the present study was to investigate the use of pulsed field gel electrophoresis (PFGE) for identifying sources of lipase and/or protease producing psychrotrophic Pseudomonas species at various pre-processing locations, and to track the types identified through the pre-processing environment. Incubation of raw milk was also carried out to simulate possible scenarios where the raw milk may be stored on the farm and in the silo prior to UHT processing. This enabled enrichment for spoilage bacteria and studies to identify sources of microorganisms that may contribute to lipolysis and proteolysis in raw and, subsequently, UHT milk or other long life dairy products. The impact of various storage conditions on the different Pulsed Field (PF) types of importance with regard to lipase and protease production was also assessed. "

Theses by Philip Button

Spoilage of UHT milk is of concern to the Australian dairy industry. Bacterial lipases and prote... more Spoilage of UHT milk is of concern to the Australian dairy industry. Bacterial lipases and proteases have been identified as a key cause of spoilage of long life dairy products. They are synthesised in raw milk by psychrotrophic Pseudomonas spp. during refrigerated storage and persist as active enzymes in dairy products owing to retention of activity after heat treatment. The continuing action of lipase and protease may cause spoilage of all long life dairy products, including UHT milk, butter and cheese.

The present study identified lipase and protease assays which could be used to detect limited lipolysis and proteolysis in UHT milk that may result in organoleptic defects during shelf life. These assays utilised the milk-like substrate triolein for lipase detection and the labelled substrate FITC-casein for protease detection. In these assays, a strong correlation was observed between the extent of hydrolysis of the substrate in the assay and the progress of lipolysis and proteolysis in milk. Furthermore, these assays could be used to detect levels of lipolysis or proteolysis that are likely to result in spoilage in UHT milk after three to five months of storage.

The progress of some biochemical changes in UHT milk has been followed during shelf life. Three trials were conducted, with storage times of up to ten months. The rate of lipolysis and proteolysis was different in each trial. The shelf life of the milk samples in the second and third trials was limited by the development of age gelation, which occurred after viscosity increased to 120-150 mPas, although there were no appreciable off-aromas or off-flavours at that stage. Age gelation was accompanied by a large decline in the -casein content, particularly in the days immediately prior to its manifestation. At no time were off-aromas or off-flavours detected. This is consistent with the absence of measurable quantities of hydrophobic peptides and free fatty acids which contribute to flavour defects, in the samples.

Psychrotrophic Pseudomonas spp. were isolated from farm, tanker and silo milk. A total of 39 PFGE Types were identified among 45 isolates which demonstrates considerable genetic diversity in Pseudomonas spp. in raw milk. Isolates from one of the farms and from the silo had the greatest potential for causing spoilage. This is because proportions of the strongly lipolytic and proteolytic isolates were higher and they grew to spoilage levels more quickly than isolates from other sources. Although incubation of the milk at 10 ºC led to faster Pseudomonas spp. growth, this growth temperature resulted in the proliferation of bacteria that were less lipolytic and proteolytic than did incubation at 4 ºC. After growing at 4 ºC, the Pseudomonas spp. were more lipolytic and proteolytic than the bacteria present in the unincubated milk.

Specificity of a typical psychrotrophic Pseudomonas spp. protease, protease B52 from Pseudomonas fluorescens B52, towards alpha-s and beta-casein was investigated. Mass spectral analysis revealed limited specificity, with the peptides released being mostly hydrophilic. This result suggests that B52 protease is unlikely to cause bitterness from degradation of alpha-s and beta-casein.

The present study has improved our basic understanding of psychrotrophic Pseudomonas spp. lipase and protease action in UHT milk, in particular, the manner in which these enzymes act on their substrates during shelf life and the development of the resulting quality defects. In addition, suitable lipase and protease substrates and assay conditions have been identified, leading to improved detection methods. The present study has also identified, in the milk collection area under investigation, sources (particular farms) and practices (particular storage temperatures and times) that may contribute to increased lipase and protease contamination of UHT milk and other long-life dairy products.

"Food spoilage results in major economic losses in the domestic and export markets as well as in ... more "Food spoilage results in major economic losses in the domestic and export markets as well as in the home. In addition, the possibility of gastrointestinal concerns arise, if the food contains an extreme number of organisms. Refrigerated, aerobically stored meat is spoiled predominantly by psychrotrophic Pseudomonas species. These include P. fragi, P. fluorescens and P. putida. Previous work in this laboratory identified psychrotrophic pseudomonads as the major spoilage organisms of pork, stored aerobically at chill temperatures. Furthermore, siderophores were identified in this study as a major component of the ability of these organisms to grow under conditions of iron-deficiency and partial characterisation of a potentially novel siderophore-mediated iron acquisition system was carried out. This present work provided further insights into the biological nature of this system, through the use of bioassays. Bioassays for detection of the E. coli siderophores aerobactin and enterochelin were used as a base on which to develop a new bioasay detection system for this potentially novel pseudomoand siderophore. Responses were investigated to various iron sources as well as supernatants containing siderophore, of varying levels of purification. In order to completely characterise the biological and genetic basis of this system, new mutants were sought by transposon mutagensis which were defective in siderophore biosynthesis. These were to be used for determination of the biosynthetic pathway, characterisation of the genes involved, a new diagnostic bioassay and ultimately, a vaccine. A separate section of work studied a number of hydroxamate producing E. coli strains, of diverse sources. These strains were part of a previous investigation in this laboratory. The aerobactin bioassay, refined during the course of this project, was utilised in screening of these strains. Previously, these strains (of diverse origin) were identified as producers of a hydroxamate of unknown type. All isolates that were hyroxamate
positive, were aerobactin positive."

Talks by Philip Button

Transition metals • Alkaline earth metals • Non-metals • Surface functionalised • Graphene • Nano... more Transition metals • Alkaline earth metals • Non-metals • Surface functionalised • Graphene • Nanoclay • Organic • Food additives • Supplements

Food product development Diverse opportunities for use as a teaching aid Outline of session • Foo... more Food product development Diverse opportunities for use as a teaching aid Outline of session • Food product development in the curriculum • Types of new products • The product development team • Product development process • Sensory evaluation • Melbourne case study of a new product

Conference Presentations by Philip Button

Insights into physiological mechanisms of enhanced virulence potential in Listeria spp.

Annals of the Royal College of Surgeons of England, 1994

Acis 2013 Proceedings of the 24th Australasian Conference on Information Systems, 2013

FoodLegal Bulletin, Apr 3, 2014

99 & Counting Medical Myths Debunked, 2013

Raw Milk: Production, Consumption and Health Effects, 2012

Insights into physiological mechanisms of enhanced virulence potential in Listeria spp.

We have the traditional science areas, which has led to a lack of interest and understanding in s... more We have the traditional science areas, which has led to a lack of interest and understanding in science among secondary school students and complaints about the lack of relevance
of science curricula. Then we have food science and technology – versatile, full of fantastically diverse scientific
principles and something students can relate to – after all, everyone eats! Why not use the science behind food
and its production and manufacture to improve engagement of your students and promote their enthusiasm? A range
of lesson ideas for direct classroom implementation will be presented, covering the spectrum of the basic sciences.

We have the traditional science areas, which has led to a lack of interest and understanding in s... more We have the traditional science areas, which has led to a lack of interest and understanding in science among secondary school students and complaints about the lack of relevance
of science curricula. Then we have food science and technology – versatile, full of fantastically diverse scientific
principles and something students can relate to – after all, everyone eats! Why not use the science behind food and its production and manufacture to improve engagement of your students and promote their enthusiasm? A range of lesson ideas for direct classroom implementation will be presented,
covering the spectrum of the basic sciences.

The field of dairy science is diverse. From the animal husbandry, veterinary science and agronomy... more The field of dairy science is diverse. From the animal husbandry, veterinary science and agronomy aspects through to
microbiology and biochemistry of dairy products and, in addition, the various industrial processes that involve engineering,
physics and chemistry. Outside of the science of dairying, politics and economics can and do have a major effect on the
industry. To date, a comprehensive publication that addresses the broad spectrum of dairy science and auxiliary areas that
effect dairy science, has been unavailable. Such a publication would be an invaluable reference resource. The Encyclopedia of
Dairy Science, edited by Hubert Roginski (editor-in-chief), is the perfect comprehensive resource, which fills this vital gap in
dairy science literature.

Men and women. This is the most fundamental division in human biology. Yet the basis for this div... more Men and women. This is the most fundamental division in human biology. Yet the basis for this division has taken an
eternity to unravel and understand. The book Adam's Curse by Oxford genetics professor Bryan Sykes is a fascinating
account of the events that have unfolded during the past 100 years or so, leading to the discovery of the basis of human sex
determination.