Seasonal Herbage Accumulation of Different Dairy Pasture Types in Southern Australia

Perennial ryegrass pastures, which are the mainstay of dairy feeding systems in southern Australia, are characterised by strong spring growth, little summer/autumn growth, and poor persistence. These limitations impose costs to farm businesses through the purchase of additional fodder to fill feed gaps, and regular re-sowing of pastures. The objective of the research reported here was to investigate the potential for alternative pasture types with different seasonal growth characteristics to improve the seasonal distribution of feed supply and overcome some of the limitations associated with perennial ryegrass

Milk Production Potential of Different Dairy Pasture Types in Southern Australia

The growth rate of traditional perennial ryegrass-based pastures commonly fails to meet herd feed requirements through winter and summer in non-irrigated dairy systems in southern Australia. Alternative pasture species can improve seasonal feed supply in this region (Tharmaraj & Chapman, 2005). However, the feeding value and milk production of these pastures must at least match perennial ryegrass if they are to be adopted successfully on dairy farms. This paper reports results of a comparison of the milk production potential of pasture types similar to those investigated by Tharmaraj & Chapman (2005) for their agronomic performance

An experimental insight of friction stir welding of dissimilar AA 6061/Mg AZ 31 B joints

In the present scenario, aerospace and automobile industries depend on lightweight materials such as magnesium and aluminum alloys because of their great balance between mechanical properties and weight ratio. Despite these benefits during the joining process of these dissimilar materials by welding, many challenges arises. The prominent one is related to the low melting points of these lightweight metals which make it almost impossible the joining using conventional arc welding techniques. To tackle this challenge, Friction Stir Welding (FSW) can be considered as a promising candidate tool. In this study, to demonstrate the FSW performances of joining two dissimilar materials we have investigated the joining of AA 6061 and Mg AZ 31 B using a built-in house a modified milling machine. The dissimilar combinations of AA 6061 and Mg AZ 31 B joints were successfully joined by embedding different welding conditions and varying the offset distance. The mechanical performances were evaluated by conducting specific mechanical tests such as micro-hardness, tensile, and impact tests, respectively. To explain the mechanical results, we have applied optical microscopy observation on the microstructure associated with the bonding location. The results prove that the strength of the Friction Stir Welded joints is much higher as compared to other techniques especially in terms of dissimilar metals

Boronic acids for sensing and other applications - a mini-review of papers published in 2013

Boronic acids are increasingly utilised in diverse areas of research. Including the interactions of boronic acids with diols and strong Lewis bases as fluoride or cyanide anions, which leads to their utility in various sensing applications. The sensing applications can be homogeneous assays or heterogeneous detection. Detection can be at the interface of the sensing material or within the bulk sample. Furthermore, the key interaction of boronic acids with diols allows utilisation in various areas ranging from biological labelling, protein manipulation and modification, separation and the development of therapeutics. All the above uses and applications are covered by this mini-review of papers published during 2013

Antimicrobial effects of probiotic bacteria against selected species of yeasts and moulds in cheese-based dips

The antimicrobial properties of selected probiotic bacteria against Aspergillus niger, Penicillium roqueforti, Fusarium spp., Candida albicans and Saccharomyces cerevisiae were examined. Well diffusion and spot and streak methods showed strong inhibition effect of probiotic bacteria and their metabolites against moulds and minimal effect against yeasts. Among the moulds species tested, the inhibitory effect was strongest against Fusarium spp., moderate against Penicillium roqueforti and minimal against A. niger. All strains of Lactobacillus rhamnosus and L. paracasei subsp. paracasei showed maximum inhibitory effect. When probiotic bacteria and yeasts and moulds were co-cultured in broth media, strains of L. rhamnosus showed maximum inhibitory effect, whereas L. paracasei subsp. paracasei, L. acidophilus, Bifidobacterium animalis and Propionibacterium showed moderate inhibitory effect against C. albicans. Saccharomyces cerevisiae was minimally controlled by probiotic bacteria. Pre-grown probiotic bacterial culture metabolites controlled yeasts and moulds more effectively than their freeze-dried or frozen forms. Adding metabolites of probiotic bacteria (5% w/w) showed an effective control against A. niger, Fusarium spp. and C. albicans during the shelf life of 10 weeks at 4 °C and no colonies of yeasts and moulds were formed on the surface of the dip. © 2009 Institute of Food Science and Technology.link_to_subscribed_fulltex

Selective enumeration of Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, bifidobacteria, Lactobacillus casei, Lactobacillus rhamnosus, and propionibacteria

Nineteen bacteriological media were evaluated to assess their suitability to selectively enumerate Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus acidophilus, bifidobacteria, and propionibacteria. Bacteriological media evaluated included Streptococcus thermophilus agar, pH modified MRS agar, MRS-vancomycine agar, MRS-bile agar, MRS-NaCl agar, MRS-lithium chloride agar, MRS-NNLP (nalidixic acid, neomycin sulfate, lithium chloride and paramomycine sulfate) agar, reinforced clostridial agar, sugar-based (such as maltose, galactose, sorbitol, manitol, esculin) media, sodium lactate agar, arabinose agar, raffinose agar, xylose agar, and L. casei agar. Incubations were carried out under aerobic and anaerobic conditions at 27, 30, 37, 43, and 45°C for 24, 72 h, and 7 to 9 d. S. thermophilus agar and aerobic incubation at 37°C for 24 h were suitable for S. thermophilus. L. delbrueckii ssp. bulgaricus could be enumerated using MRS agar (pH 4.58 or pH 5.20) and under anaerobic incubation at 45°C for 72 h. MRS-vancomycine agar and anaerobic incubation at 43°C for 72 h were suitable to enumerate L. rhamnosus. MRS-vancomycine agar and anaerobic incubation at 37°C for 72 h were selective for L. casei. To estimate the counts of L. casei by subtraction method, counts of L. rhamnosus on MRS-vancomycine agar at 43°C for 72 h under anaerobic incubation could be subtracted from total counts of L. casei and L. rhamnosus enumerated on MRS-vancomycine agar at 37°C for 72 h under anaerobic incubation. L. acidophilus could be enumerated using MRS-agar at 43°C for 72 h or Basal agar-maltose agar at 43°C for 72 h or BA-sorbitol agar at 37°C for 72 h, under anaerobic incubation. Bifidobacteria could be enumerated on MRS-NNLP agar under anaerobic incubation at 37°C for 72 h. Propionibacteria could be enumerated on sodium lactate agar under anaerobic incubation at 30°C for 7 to 9 d. A subtraction method was most suitable for counting propionibacteria in the presence of other lactic acid bacteria from a product. For this method, counts of lactic bacteria at d 3 on sodium lactate agar under anaerobic incubation at 30°C were subtracted from counts at d 7 of lactic bacteria and propionibacteria.link_to_subscribed_fulltex

Survival of Lactobacillus acidophilus, Lactobacillus paracasei subsp. paracasei, Lactobacillus rhamnosus, Bifidobacterium animalis and Propionibacterium in cheese-based dips and the suitability of dips as effective carriers of probiotic bacteria

The suitability of cheese-based dips as a delivery vehicle for probiotic bacteria including Lactobacillus acidophilus, Lactobacillus paracasei subsp. paracasei, Lactobacillus rhamnosus, Bifidobacterium animalis, and Propionibacterium freudenreichii subsp. shermanii was studied by evaluating the survival of these organisms in dips. Effects of organic acids, oils and gums, L-cysteine and NaHCO3 on the survival of probiotics in cheese-based dips were also studied. Eight different combinations and five individual bacteria as controls of these probiotic bacteria were added to 21 batches of French onion dip and selective enumeration of these probiotic bacteria was carried out over a period of 10 weeks of storage. The population of L. acidophilus and B. animalis reduced by 1 log and 2 log per g, respectively. However, when the inoculation level of these bacteria were increased to 8 log per g, they maintained a population of more than 6 log over the shelf life. L. paracasei subsp. paracasei and L. rhamnosus remained at the inoculated level or increased slightly during the storage. A rapid increase in the population of P. freudenreichii subsp. shermanii occurred to attain more than the inoculation level following reduction in their number by 3 log. Except bacterial interaction, no other factors showed significant effect on the survival of individual probiotic bacteria. Each of L. acidophilus, B. animalis, L. paracasei subsp. paracasei, and L. rhamnosus showed varied levels of antogonism, while P. freudenreichii subsp. shermanii showed no effect. Any combination of these bacteria can be used as probiotics in cheese-based French onion dip. However, the inoculation level should be 8 log per g for L. acidophilus and B. animalis and 7 log per g for L. paracasei subsp. paracasei, and/or L. rhamnosus to obtain greater than 6 log of individual bacterial population at the end of shelf life. © 2004 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex

Antimicrobial effects of probiotics against selected pathogenic and spoilage bacteria in cheese-based dips

Spot-on lawn, spot and streak, co-culturing techniques and HPLC analysis were used for the detection and screening of inhibitory activity produced by probiotic bacteria against spoilage and pathogenic bacteria. After incubation, plates were examined for either zones of inhibition and for other effects of suppression around the wells/spots and streaks or cfu/g of target bacteria. The spore-formers were inhibited by the probiotic organisms to a greater extent than the non-spore formers. The inhibitory effect of all probiotic bacteria was weakest against E. coli and strongest against B. cereus. S. aureus was inhibited to a greater extend by B. animalis and by L. rhamnosus. The order of probiotic bacteria in terms of level of inhibition on agar plates (and zone of inhibition in mm) was L. rhamnosus (21)> L. acidophilus (19) = L. casei (19) > L. paracasei subsp. paracasei (18) > B. animalis (15) > P. freudenreichii subsp. shermanii (11). Though co-culturing of target organisms with probiotic bacteria in reconstituted skim milk showed inhibitory effect against target organisms; however, in French onion dip, there was no additive effect in controlling the bacterial population except that for B. cereus. Varying quantities of organic acids (acetic, lactic, formic, propionic, butyric, benzoic and phenyllactic) that were responsible for the inhibition were detected. © All rights reserved.link_to_subscribed_fulltex