The microflora of Tilsit cheese. Part 1. Variability of the smear flora

The microflora of 25 Tilsit cheeses from 2 cheese plants was analysed. Debaryomyces hansenii was found to be the predominant yeast in all stages of ripening. 75–95% of the bacterial flora consisted of coryneform bacteria. Several of the isolates were identified as Arthrobacter. Brevibacterium linens was found at 0-15%. In all cheeses tested, 5-15% of total cell counts were made up by staphylococci. They were determined as being not Staphylococcus aureus or other pathogenic staphylococci since all isolates were negative with respect to thermo-nuclease, clumping, coagulase, and hemagglutination. Most of the isolates were hemolysis negative. By genetical analysis, several selected isolates were classified as Staphylococcus equorum, one isolate as S. sciuri. Contamination of cheeses with Fusarium moulds indicated the influence of the smearing strategy on spreading of undesirable microorganisms. In plant A, old cheeses were smeared first, then young cheeses were smeared with the same smear liquid. Fusarium contamination could be detected in all stages of ripening. In plant B, young cheeses (0-3 weeks) were smeared with a commercial surface starter cocktail. In all cheeses of this age, problems with Penicillium contaminations were observed. Older cheeses (>3 weeks) were smeared according to the strategy applied in plant A. Consequently, Fusarium moulds were detected in cheeses 4-8 weeks of age.     

A diminished role for hydrogen bonds in antifreeze protein binding to ice

The most abundant isoform (HPLC-6) of type I antifreeze protein (AFP1) in winter flounder is a 37-amino-acid-long, alanine-rich, alpha-helical peptide, containing four Thr spaced 11 amino acids apart. It is generally assumed that HPLC-6 binds ice through a hydrogen-bonding match between the Thr and neighboring Asx residues to oxygens atoms on the {2021} plane of the ice lattice. The result is a lowering of the nonequilibrium freezing point below the melting point (thermal hysteresis). HPLC-6, and two variants in which the central two Thr were replaced with either Ser or Val, were synthesized. The Ser variant was virtually inactive, while only a minor loss of activity was observed in the Val variant. CD, ultracentrifugation, and NMR studies indicated no significant structural changes or aggregation of the variants compared to HPLC-6. These results call into question the role of hydrogen bonds and suggest a much more significant role for entropic effects and van der Waals interactions in binding AFP to ice.     

Monolithically Integrated InP 1 $times$ 16 Optical Switch With Wavelength-Insensitive Operation

The static and dynamic characteristics of a monolithically integrated InP 1$,times,$ 16 optical phased-array switch are presented. The device demonstrates static switching with an average extinction ratio of 18.6 dB, on-chip loss below 7 dB, and wavelength dependence of less than 0.8 dB in the entire $C$-band. A 40-Gb/s nonreturn-to-zero signal is transmitted through the switch with a power penalty below 0.4 dB. Using a programmable electronic circuit, dynamic switching to all 16 outputs is achieved with response times less than 11 ns.      

Flavour- and tenderness-related quality characteristics of goat and sheep meat

The quality characteristics of 27 Angora goats, Boer goats and sheep carcases were compared. Significant differences exist between the quality characteristics of sheep meat and Angora or Boer goat meat. Sheep meat has a more intense aroma, it is more tender, contains less fibrous tissue residue and the species flavour is more pronounced (typical) than that of Angora and Boer goat meat. In general, goat meat was found to be significantly different to sheep meat, the Angora to a lesser extent, however, than the Boer goat. This study confirms the fact that the meat of younger animals is more tender, contains less fibrous tissue residue and the species flavour is less typical than that of older animals. This was irrespective of whether it was obtained from sheep, Angora or Boer goat. With increasing fatness of carcases, the tenderness and species flavour of the cooked cuts increased significantly.     

Developments in mineralogical techniques - What about mineralogists?

Conventional mineralogy was mainly based on optical microscopic techniques. Years of experience in studying ore and gangue minerals using an optical microscope allowed for quick identification of minerals, opinions on abundances of certain minerals, liberation, required grind size and reasons for high mass pulls or tailings losses. More detailed investigations involving point counting techniques, XRD and chemical methods provided additional information to quantify certain aspects of the problem studied.Developments in automation of SEM-based techniques, computerised XRD processing and identification, imaging software, etc. has impacted on the tasks of mineralogists. Future equipment developments and the implementation of plant systems will probably minimise the need for experienced mineralogists for the more routine applications.This publication discusses how processing requirements have driven developments on current systems. The changing role of mineralogists is discussed, as well as knowledge and experience requirements to drive applied or process mineralogy forward.