The bulk density of milk powders is economically, commercially and functionally an important property. When shipping powders over long distances, the producers are interested in high bulk density to reduce the shipping volume, since in most cases the transportation costs are by volume. Also, high bulk density saves in packaging material. This review article would interest producers who are looking for high bulk density in milk powders.

The butterfat in milk or cream undergoing bacteriological deterioration extracts fat-soluble tainting substances as they are formed. In low fat test dairy fluids, because of the high proportion of plasma to fat, the quantity of tainting substance available for extraction is greater than in high test fluids. It is suggested that this is the reason why butter from cream factory-separated from poor quality milk is often inferior to butter from farm-separated cream of similar bacteriological quality.

Until recently it was considered that variation in the acidity of cream for sweet cream buttermaking had little influence on the amount of butterfat lost in the buttermilk during churning (Wiley 1939, McDowall 1953 (a)). This, however, applied to acidities approximating to those of fresh cream. Over the last few years cream for buttermaking in Australia has been neutralised to lower and lower acidities in the interests of keeping quality, and parallel with this, greater losses of butterfat in churning have been encountered. This phenomenon of higher fat losses with low cream acidity had been reported in New Zealand (McDowall 1953 (b)) and the explanation according to Dolby (1957 (a)) is that the shattering with agitation of the butterfat globules into smaller globules with resultant higher losses in the buttermilk in churning, becomes more pronounced as the pH increases. The agitation causing the breaking up of the globules occurs where the cream and steam velocities are hight (Dolby 1957 (b) (c)). This study covers observation under experimental factory conditions over two complete seasons of the influence of cream acidity on these losses.

This paper examines the effect of pH, added calcium and added phosphate on the formation of rennet gels and aspects of the structure of curd in light of the dual binding model of caseincasein interactions (Horne 1998). It is seen that the dual binding model is important in understanding the stability of aggregates but that a more detailed consideration of aggregate structure is required for the understanding of the interactions between aggregates that are an important part of the phenomena described.

A sub-optimal intake of calcium appears to be related to an increase in intracellular calcium in many tissues. In adipose tissue, this phenomenon is accompanied by a decreased lipolysis of fat cells relative to their lipogenic potential whereas in skeletal muscle this might reduce the oxidative capacity of myocytes. This is concordant with human studies showing that a low calcium intake predicts a decrease in body fat oxidation and an increase in body fatness. In a clinical context, the supplementation of calcium was found to accentuate the fat loss induced by a dietary energy deficit. This effect was even greater when a high dairy diet was used to promote calcium supplementation. Some research data also demonstrate that the beneficial effects of calcium/dairy food supplementation on fat balance are associated with a decreased risk to develop the insulin resistance syndrome, including a lower risk towards dyslipidemias.

This article describes the importance of controlling the rate and extent of acid development, as this dictates the loss of calcium during cheesemaking. The amount and the state of the retained calcium influences the physical characteristics of cheese during ripening. Calcium also impacts the functional attributes of cheese during heating or baking. Changes in the physical properties of cheese during ripening occur in two stages: one is governed by pH and changes to the insoluble calcium content and this may take hours, days or weeks to be fully realised; the other stage is governed by the extent of proteolysis of intact casein that occurs throughout cheese ripening. The importance of controlling the factors that are involved in the initial stage of ripening is described and suggestions are offered on how this can be accomplished.

Marketing and the environment are not necessarily good friends, as they often have diverging goals. Marketing is focused on seducing consumers and generating profitable sales rapidly, and generally takes the environment into consideration only as far as it helps in achieving that goal. However, some brands have made successful use of 'green marketing'. Using the examples of three brands that have used it differently - Valvert minerals waters, Yoplait fruit yogurt and Stonyfield Farm dairy products - it is possible to identify a few rules about efficient green marketing. Overall, the two basic requirements of green marketing appear to be top management involvement and long-term objectives that include the will to educate consumers. It may not be possible to calculate how much or how fast you can make money by going 'green', but one thing is sure, not integrating environmental issues in your marketing and processes could end up a costly decision.

Summary of an address given on the care and propogation of starter cultures for cultured milk products.

Graphs outlining total cattle populations from 1830-1950 in Queensland, NSW and Victoria.

Infectious disease in man is controlled primarily by immunisation. For example, smallpox has been eradicated worldwide in man by immunisation programs. The second most effective control measure known to science is the use of drugs and antibiotics targeted to block the infectious process in vivo, i.e. by modifying the chemistry of the environment in vivo so that infection and/or toxin formation is blocked. Both these approaches for control of foodborne diseases are mostly ignored by the food industry and food safety regulators, and take second place to the less effective measure of trying to remove all infectious agents from food by setting low limits for pathogens in foods. The dairy industry is well placed to use these more effective measures in food safety because milk contains compounds that confer gut immunity to pathogens, and fermented dairy foods, such as cheese and yogurt, contain live lactic-acid bacteria that provide a second level of gut immunity. It is proposed that public health is better served by food safety standards that recognise 'immunity factors' in food and that chemical standards of identity of foods are essential and are a better indicator of food safety than microbiological limits.

Milk was collected from cows fed four diets consisting of a control (C), C with 2% fish oil (FO), C with 1% each of fish oil and extruded soybeans (FOES), and C with 2% extruded soybeans (ES). Milks were processed and fermented with a starter culture comprised of yogurt (S. thermophilus and L. delbrueckii ssp. bulgaricus) and probiotic (L. acidophilus and bifidobacteria) bacteria. Changes in the fatty acid composition of yogurt mix and yogurt during manufacture and storage were monitored. Also, changes in viable numbers of starter bacteria were monitored in fresh yogurt and after 30 d storage. Milkfat of cows fed C, FO, FOES, and ES diets were 3.31%, 2.58%, 2.94% and 3.47%, respectively. Milk, yogurt mix and yogurt from cows fed with FO or FOES diets showed a 4-fold increase (p<0.05) in the concentration of conjugated linoleic acid (CLA) and an increase (p<0.05) in omega-3 fatty acids. The same diet group products also had increased concentrations of transvaccenic acid (TVA). Unsaturated fatty acids were higher in the milk from cows fed with FO, FOES, and ES diets compared to the C diet. The processing of milk (incorporation of milk powder and heat treatment at 85°C for 30 min) had no effects (p>0.05) on fatty acids composition, especially CLA, TVA, and omega-3 fatty acids. Further, changes in fatty acids composition (as a result of change in diet) did not show any significant effects on the viable numbers of starter bacteria. Viable numbers of yogurt bacteria were >107/g and probiotic bacteria were >105/g at the end of 30 d storage periods. Fermentation with yogurt and probiotic bacteria and storage did not alter (p>0.05) the CLA, TVA, or omega-3 fatty acids. Thus, probiotic yogurt made from milk with increased CLA and TVA can be produced by changing the diets of cows and it could offer health benefits to consumers.

A number of strains of Streptococcus cremoris, produced by the factory-derived whey adapted starter system were analysed. Some of the phage-resistant derivatives differed from their parent strains as they were able to hydrolyze arginine and/or possessed different plasmid DNA profiles. The slow acid production of one derivative of S. cremoris E8 was due to a decrease in the growth and proteinase activity of the derived culture. Resting cells of many of the derived cultures showed a decreased ability to matabolize pyruvate.

The industrial manufacture and ripening of three batches of idiazábal cheese made from raw ewe's milk during the winter lactation period were studied. Counts of aerobic mesophiles and pyschrotrophs in the cheese made using starters were~1 log unit lower, and counts of enterococci were ~2 log units lower. Furthermore, enterobacteriaceae and coliforms were no longer detectable in the cheeses after 30 d of ripening, while in the cheeses made without starter, counts of these two microbial groups were still of the order of 10² cfu/g after 60 d. Batches with added starter exhibited higher levels of lactic acid bacteria, especially during pressing, though no differences were observed during ripening. Differences in the levels of micrococcaceae, moulds, and yeasts between the three batches were slight. The pH of the starter-containing batches was lower, particularly at the end of pressing. During cheese ripening differences in pH were smaller. The quality of the cheeses from the three bathces was that required by the Appellation of Origin Idiazábal. Flavours of all cheeses were typical of matured ewe's milk cheese.

Homogenized milks were pasteurized at 15 different temperature/time combinations in the ranges of 72°C to 88°C and 1s to 45s, packaged under aseptic conditions and stored at 3°C and 7°C until spoiled. Bacteria were isolated for identification from the milks immediately after pasteurization and at spoilage. The average initial microflora was dominated by coryneforms (83.8%) with a smaller proportion of Gram positive cocci (12.8%) and a low proportion of Bacillus (3.4%). Increased severity of pasteurization caused decreases in the proportion of Gram positive cocci in freshly pasteurized milk. However, despite a varied microflora in all milk samples immediately after pasteurization, aseptic packaging of the product resulted in Bacillus circulans dominating in all milks at the end of shelf life. This dominance by B. circulans was not affected by the different pasteurization or storage conditions used.

A number of authors have shown correlations between consumption of milk, or specific milk proteins, and ischaemic heart disease (IHD) in between-country ecological studies (Seely 1981, 1984; McLachlan 2001; Laugeson & Elliott, 2003).This paper looks at the trend over time of such correlations for milk and a range of other foods. Any causative relationship would be expected to give a consistent correlation; a changing correlation points to other, possibly linked, causative factors.