Australian Journal of Dairy Technology 

About: Australian Journal of Dairy Technology is an academic journal. The journal publishes majorly in the area(s): Skimmed milk & Casein. It has an ISSN identifier of 0004-9433. Over the lifetime, 827 publications have been published receiving 12804 citations.

Comparative survival of probiotic lactobacilli spray dried in the presence of prebiotic substances

Abstract: AIMS Probiotic milk-based formulations were spray-dried with various combinations of prebiotic substances in an effort to generate synbiotic powder products. METHODS AND RESULTS To examine the effect of growth phase and inclusion of a prebiotic substance in the feed media on probiotic viability during spray-drying, Lactobacillus rhamnosus GG was spray-dried in lag, early log and stationary phases of growth in reconstituted skim milk (RSM) (20% w/v) or RSM (10% w/v), polydextrose (PD) (10% w/v) mixture at an outlet temperature of 85-90 degrees C. Stationary phase cultures survived best (31-50%) in both feed media and were the most stable during powder storage at 4-37 degrees C over 8 weeks, with 30-140-fold reductions in cell viability at 37 degrees C in RSM and PD/RSM powders, respectively. Stationary phase Lact. rhamnosus GG was subsequently spray-dried in the presence of the prebiotic inulin in the feed media, composed of RSM (10% w/v) and inulin (10% w/v), and survival following spray-drying was of the order 7.1-43%, while viability losses of 20,000-90,000-fold occurred in these powders after 8 weeks' storage at 37 degrees C. Survival of the Lactobacillus culture after spray-drying in powders produced using PD (20% w/v) or inulin (20% w/v) as the feed media was only 0.011-0.45%. To compare different probiotic lactobacilli during spray-drying, stationary phase Lact. rhamnosus E800 and Lact. salivarius UCC 500 were spray-dried using the same parameters as for Lact. rhamnosus GG in either RSM (20% w/v) or RSM (10% w/v) and PD (10% w/v). Lact. rhamnosus E800 experienced approx. 25-41% survival, yielding powders containing approximately 10(9) CFU g(-1), while Lact. salivarius UCC 500 performed poorly, experiencing over 99% loss in viability during spray-drying in both feed media. In addition to the superior survival of Lact. rhamnosus GG after spray-drying, both strains experienced higher viability losses (570-700-fold) during storage at 37 degrees C over 8 weeks compared with Lact. rhamnosus GG. CONCLUSIONS Stationary phase cultures were most suitable for the spray-drying process, while lag phase was most susceptible. The presence of the prebiotics PD and inulin did not enhance viability during spray-drying or powder storage. SIGNIFICANCE AND IMPACT OF THE STUDY High viability (approximately 10(9) CFU g(-1)) powders containing probiotic lactobacilli in combination with prebiotics were developed, which may be useful as functional food ingredients for the manufacture of probiotic foods.

Milk fat in human nutrition

Abstract: Milk fat contains a number of components of nutritional significance. The first section of the review outlines the composition, structure and certain biochemical and physiological characteristics of these components. In recent times the nutritional image of milk fat has suffered adversely because of the association of saturated fat and cholesterol with coronary heart disease. The various elements that are used to justify this 'lipid-heart disease' hypothesis are discussed and the strength of the evidence is assessed. Contrary evidence, which is mostly overlooked in authoritative reviews, is presented. Trans fatty acid consumption is associated with an increased risk of coronary heart disease; however, the associations generally do not apply to trans acids of animal origin. These acids are mainly vaccenic and rumenic, acids that may possess anti-atherogenic properties. Other health related benefits for rumenic acid, particularly its role in the prevention of mammary tumorigenesis are outlined. Milk fat contains other potential anticancer agents such as sphingomyelin and other sphingolipids, butyric acid, 13-methyltetradecanoic acid, ether lipids and vitamin A. Pasture-derived compounds like β-carotene, β-ionone, gossypol and phytol may also help prevent cancer. Finally, the review discusses the antimicrobial action of milk fat and its role in long-chain polyunsaturated fatty acid metabolism, bone growth, ulcerogenesis, and energy metabolism.

L. acidophilus and Bifidobacterium spp.--their therapeutic potential and survival in yogurt

Abstract: This paper presents an overview of the probiotic organisms used as live supplements, with emphasis on Lactobacillus acidophilus and Bifidobacterium spp., their therapeutic potential and their survival during the manufacture and storage of yogurt. The factors affecting viability of these probiotic bacteria and ways of improving their survival are also discussed. L. acidophilus and Bifidobacterium spp. have been reported to provide excellent therapeutic benefits; their incorporation into yogurt, therefore, improves it as a therapeutic functional food. However, poor viability and survival of these bacteria remain a problem in commercial yogurts. Selecting better functional probiotic strains and adopting improved methods of enhancing survival could increase delivery of viable beneficial bacteria to yogurt consumers.

Effects of mastitis on raw milk and dairy products.

Abstract: This review covers scientific and technical publications from 1982 to 1996 on the influence of mastitis, both clinical and subclinical, on raw milk yield and composition and dairy product yield and quality. In some cases, earlier references are provided for clarification. It provides an update for the reviews of Kitchen (1981) and Munro et al. (1984). The review examines somatic cell count (SCC) as a measure of mastitis; the effect of SCC on the yield and quality of raw milk and dairy products; the SCC threshold affecting milk products ; seasonality and late-lactation milk; milk quality incentive schemes for SCC; and mastitis control practices and SCC. The literature reviewed confirms the deleterious effects of mastitis on milk composition and the yield and quality of dairy products. Other factors that alter milk composition (e.g. season, stage of lactation, nutrition) sometimes confound the precise effects of SCC. A SCC standard of 400,000 cells/mL for bulk milk is being adopted in milk quality schemes around the world as a result of the European Union requirements which apply from January 1998. This level will minimise the effects of mastitis on product quality, although negative effects on product quality have been reported for milk with a SCC as low as 100,000 cells/mL. Further, a bulk milk somatic cell count of 400,000 cells/mL indicates that around 40% of cows in a herd are infected.