The microstructure and physicochemical properties of probiotic buffalo yoghurt during fermentation and storage: a comparison with bovine yoghurt

The physicochemical and rheological properties of yoghurt made from unstandardised unhomogenised buffalo milk were investigated during fermentation and 28 days of storage and compared to the properties of yoghurt made from homogenised fortified bovine milk. A number of differences observed in the gel network can be linked to differences in milk composition. The microstructure of buffalo yoghurt, as assessed by confocal laser scanning microscopy (CLSM) and cryo scanning electron microscopy (cryo-SEM), was interrupted by large fat globules and featured more serum pores. These fat globules have a lower surface area and bind less protein than the homogenised fat globules in bovine milk. These microstructural differences likely lead to the higher syneresis observed for buffalo yoghurt with an increase from 17.4 % (w/w) to 19.7 % (w/w) in the weight of whey generated at days 1 and 28 of the storage. The higher concentration of total calcium in buffalo milk resulted in the release of more ionic calcium during fermentation. Gelation was also slower but the strength of the two gels was similar due to similar protein and total solids concentrations. Buffalo yoghurt was more viscous, less able to recover from deformation and less Newtonian than bovine yoghurt with a thixotropy of 3,035 Pa.s-1 measured for buffalo yoghurt at the end of the storage, at least four times higher than the thixotropy of bovine yoghurt. While the titratable acidity, lactose consumption and changes in organic acid concentrations were similar, differences were recorded in the viability of probiotic bacteria with a lower viability of Lactobacillus acidophilus of 5.17 log (CFU/g) recorded for buffalo yoghurt at day 28 of the storage. Our results show that factors other than the total solids content and protein concentration of milk affect the structural properties of yoghurt. They also illustrate the physicochemical reasons why buffalo and bovine yoghurt are reported to have different sensory properties and provide insight into how compositional changes can be used to alter the microstructure and properties of dairy products. © 2013 Springer Science+Business Media New York.

Wastewater reuse and treatment options for the dairy industry

Milk-processing plants generate significant quantities of wastewater with relatively high organic matter concentrations on a daily basis. In addition to environmental damage that can result from the discharge of these wastewaters into the natural waterways, the presence of products such as milk solids into wastewater streams represents a loss of valuable product for the plants. This paper presents a review of wastewater management practices employed by six milk-processing plants in Victoria, Australia. In all six plants investigated, milk powder represents a major product. During the milk powder production, water is evaporated, condensed and can be reused for various purposes with a significant impact on water usage. Other major products are anhydrous milk fat, cheese, butter, and UHT milk. The effectiveness of the practices was assessed through two main criteria: first through the water to milk intake ratio, and the waste volume coefficient. Both parameters characterise the plant efficiency in regard of water consumption and water reuse, Information on cleaning chemical usage and recovery was also assessed as part of the review. Significant discrepancies emerge between the plants first due to the products manufacturad and water reuse possibilities available in each plant. Second the type of treatment technologies used for condensate and cleaning solution influences the figures. One of the investigated plants is almost self-sufficient for water, emphasising the benefits gained from the use of technologies like membrane separations for condensate and cleaning solution treatment. In some cases, less cost-intensive technologies such as a clarifier are successful to improve cleaning agent recovery.

Estimating the economic value of Mount Buffalo National Park with the travel cost and contingent valuation models

The Mount Buffalo National Park is the oldest national park in Victoria, Australia. There has been a rapid increase in the number of visitors to the park during the last decade and park management has been a concern, especially in the light of declining budgetary allocations and potential damage due to the increased visitor numbers. Policy options to increase park revenue remain unclear because of a lack of information on demand parameters and user costs. This study estimates the economic value of the park using the travel cost method (TCM) and the contingent valuation method (CVM). The TCM gives higher consumer surplus (CS) than the CVM. The CS shows that the economic value of the park is high and that there are opportunities to introduce innovative fee schemes to enhance its revenue. Present entry fee systems do not capture the economic value of the park.

Sodium adsorption using activated alumina for application in the dairy industry

Basic activated alumina with negatively charged surface is considered as a potential adsorbent for a targeted molecule with positive polarity. Adsorption of sodium by basic activated alumina was investigated as a method for desalting dairy waste streams, in which sodium ion concentration averaged 600 mg/L. Sodium equilibrium and kinetic adsorption were investigated using basic activated alumina with synthetic brines. The results of equilibrium adsorption show that uptake of sodium by activated alumina is significantly higher when the pH is greater than 8 and increases as the pH of the brines increases until pH reaches around 10. The results of kinetic adsorption show that 90 hours were needed to reach equilibrium for sodium adsorption. Binding and diffusion processes are suggested to have taken place within the activated alumina.

Incorporating environmental impacts into productivity analysis: the case for nitrogen leaching in the Australian dairy industry

This paper examines how the adoption of a system's perspective to the use of both marketed and public resources can be incorporated into an analysis of productivity measurement.  A biophysical model is used to measure the environmental inputs which are combined with conventional marketed inputs to develop a Malmquist Productivity Index to determine social productivity growth over the perios under study.  The analysis is applied to data collected from selected farms in south west Victoria and includes a measure of leaching and run-off as a proxy measure of the impact the application of fertilizers has on ground and surface water.  Although the sample is small, the results show measured productivity growth differs when environmental factors are considered.

Input usage, output mix and industry deregulation: an analysis of the Australian dairy manufacturing industry

In this paper we estimate a Translog output distance function for a balanced panel of state level data for the Australian dairy processing sector. We estimate a fixed effects specification employing Bayesian methods, with and without the imposition of monotonicity and curvature restrictions. Our results indicate that Tasmania and Victoria are the most technically efficient states with New South Wales being the least efficient. The imposition of theoretical restrictions marginally affects the results especially with respect to estimates of technical change and industry deregulation. Importantly, our bias estimates show changes in both input use and output mix that result from deregulation. Specifically, we find that deregulation has positively biased the production of butter, cheese and powders.

The challenge for the dairy industry arising from the new health claims standard: an impetus for innovation

The publication of a Preliminary Final Assessment Report on 4 April 2007 heralded another step towards the introduction of a new Health Claims Standard to be inserted into the Australia New Zealand Food Standards Code. This Health Claims Standard, once approved by the Board of Food Standards Australia New Zealand and by the Australia New Zealand Food Regulation Ministerial Council, will permit the making of certain substantiated health claims. Prior to the introduction of the new Standard, health claims have not been permitted on food labels, with the exception of claims in relation to maternal folate consumption and its positive effect in reducing the risk of foetal neural tube defects. The new Health Claims Standard as outlined in the Preliminary Final Assessment Report is likely to have a significant impact on the dairy industry. This paper seeks to analyse that impact, including threats, opportunities and challenges that the Standard poses to the dairy industry and other food suppliers.

Efficiency measurement of Australian dairy farms: national and regional performance

In this paper we use Data Envelopment Analysis (DEA) to estimate technical efficiency for a sample of 1742 Australian dairy farms. Bearing in mind data limitations we find that average technical efficiency is 59 per cent, but there are significant regional differences. These results reflect differences in State level milk marketing arrangements in place before dairy deregulation in July 2000 providing an ex post explanation for the changing composition of dairy farms in Australia. We also examine two important technical aspects of DEA implementation. First, how changes in model input specification alter the relative performance of farms. Second, we employ a simple bootstrap procedure to show how changes in sample size affects estimates of technical efficiency. These results have simple but important implications for the use of DEA as an industry-benchmarking tool.

Scale efficiency in Australian dairy farms

Data Envelope Analysis, (DEA), a linear programming technique, provides a more consistent measure of efficiency than the commonly cited partial measures of farm efficiency. It yields a relative measure of efficiency and identifies inputs or outputs that are under utilized.

In this paper, DEA is used to assess the technical efficiency of a sample of dairy farms across all dairy regions in Australia. Regions vary in size and scale of operation and are examined to see the relationship between farm size and technical efficiency, and to see if there is justification in the move towards bigger dairy production units than currently exist, given their factor mix.

Environmental efficiency : meaning and measurement and application to Australian dairy farms

Technical efficiency has been widely studied in the literature, but in its pursuit, many of the inputs used can impact on the environment. Environmental effects can be modelled as undesirable output or, as has been the case in more recent studies, as conventional inputs. This paper examines the concept of environmental efficiency and how it can be used to evaluate the performance of Australian dairy farming, using nitrogen surplus, arising from excessive applications of fertilizer, as a detrimental input. Farming promotes the image of clean and green production and if this image is to be maintained, there is a need to ensure activities are environmentally friendly.