Microbial food cultures have directly or indirectly come under various regulatory frameworks in the course of the last decades. Several of those regulatory frameworks put emphasis on "the history of use", "traditional food", or "general recognition of safety". Authoritative lists of microorganisms with a documented use in food have therefore come into high demand. One such list was published in 2002 as a result of a joint project between the International Dairy Federation (IDF) and the European Food and Feed Cultures Association (EFFCA). The "2002 IDF inventory" has become a de facto reference for food cultures in practical use. However, as the focus mainly was on commercially available dairy cultures, there was an unmet need for a list with a wider scope. We present an updated inventory of microorganisms used in food fermentations covering a wide range of food matrices (dairy, meat, fish, vegetables, legumes, cereals, beverages, and vinegar). We have also reviewed and updated the taxonomy of the microorganisms used in food fermentations in order to bring the taxonomy in agreement with the current standing in nomenclature.

Lactococcal phages are classified according to morphology and DNA homology. Phages are differentiated into 12 phage species, and type phages of each species are proposed. Members and possible members of each species are named. Available data on type phages are tabulated including morphology, DNA characteristics and phage protein bands.

Seven Lactobacillus strains were cultured anaerobically at 37°C for 48 h in 12% (w/v) reconstituted skim milk containing 5% (w/v) Hi-maize, lactulose, inulin, or raftilose. Their viability was determined before and after 4 wk of storage at 4°C. Doubling time (T d ) was also determined. Concentrations of acetic and lactic acids produced during fermentation and storage were determined. The T d ranged from 301 to 751 min. In general, the viability of lactobacilli after storage was greatest with inulin. The pH after storage in skim milk ranged from 4.34 (for ASCC 1520 with raftilose) to 4.10 (for ATCC 15820 with inulin). Survival of lactobacilli in prebiotic was strainspecific, but in general their survival was enhanced.

Aims: Five species of the Gram-positive bacterial genus Lactococcus (Lactococcus lactis, L. garvieae, L. plantarum, L. piscium and L. raffinolactis) are currently recognized. The aim of this work was to develop a simple approach for the identification of these species, as well as to differentiate the industrially important dairy subspecies L. lactis subsp. lactis and L. lactis subsp. cremoris. Methods and Results: Methods were devised based on specific polymerase chain reaction (PCR) amplifications that exploit differences in the sequences of the 16S ribosomal RNA genes of each species, followed by restriction enzyme cleavage of the PCR products. The techniques developed were used to characterize industrial cheese starter strains of L. lactis and the results were compared with biochemical phenotype and DNA sequence data. Conclusions: The PCR primers designed can be used simultaneously, providing a simple scheme for screening unknown isolates. Strains of L. lactis show heterogeneity in the 16S ribosomal RNA gene sequence. Significance and Impact of the Study: This work provides an integrated set of methods for differentiation and identification of lactococcal species associated with agricultural, veterinary, medical and processed food industries.

Benthic crustaceans such as the blue crab Callinectes sapidus use various sensory appendages to navigate chemical plumes. We characterized the role of different sensory structures in blue crabs during olfactory search by deafferenting (i.e. removing or rendering inactive) particular sensor populations and by quantifying odor-plume structure and flow dynamics. Our results indicate that blue crabs use both cephalic and thoracic appendages for olfactory-mediated orientation. Cephalic chemosensor deafferentation decreased search success, reduced walking speed and increased the duration of stationary periods. All these deficiencies are manifestations of the inability of crabs to sustain upstream progress. Crabs subjected to deafferentation of thoracic sensilla failed to correctly track the narrowing plume and showed an increased frequency of large course-corrections. Whereas cephalic sensors clearly function in motivating upstream movement during the search process, thoracic receptors aid in source localization. The differing functional roles of these 2 sets of appendages may be associated with different signal characteristics impinging on their chemosensor populations. Intermittent but intense signals received by the cephalic appendages may enable the crabs to identify attractive odors and sustain searching. Chemical signals impinging on legs are more homogeneous and may allow the crabs to acquire better information on the spatial patterns of chemical signal structure that are important for navigation. The simultaneous use of chemical signals at differing heights in the plume suggest that the 3D structure of these plumes is important for foraging success, and that different populations of neural receptors may be tuned to operate optimally in particular signal environments.

The effect of shear rate and oxygen injury during atomization and the combination of these factors on the survival of Lactococcus lactis subsp. cremoris in spray drying was studied using laboratory and pilot scale spray dryers. The atomization was carried out using a two-fluid nozzle in the laboratory study and a two-fluid nozzle or rotary atomizer in the pilot scale study. The extent of oxygen-induced death was determined using ascorbic acid in the feed and atomizing the feed with gaseous nitrogen. The lowest levels of bacterial death were observed at lowest characteristic shear rate and in the presence of nitrogen and ascorbic acid. Quantitative analysis showed that lower shear rate, creating an oxygen-limiting environment during atomization and drying, and using oxygen scavengers in the feed were successful in enhancing bacterial survival in spray drying. We also report for the first time that, at least for L lactis, the extent of death during the atomization stage far outweighs death during the drying stage, and that the majority of bacterial death (up to 93%) occurs during the atomization stage. The death of bacteria was found to be less when using a rotary atomizer or when using a two-fluid nozzle atomizer at lower flow rate. This work shows that bacterial death during spray drying can be minimized by using oxygen scavengers such as ascorbic acid and/or an anaerobic atomizing medium (such as nitrogen), and by altering the spraying conditions. (c) 2012 Elsevier Ltd. All rights reserved.Dairy Innovation Australia [08210C]; IDP Education Australi

An electroporation procedure for the plasmid-mediated genetic transformation of intact cells of Streptococcus cremoris and Streptococcus lactis was performed. Ten different strains were transformed. The method was simple and rapid and yielded transformant colonies in 14 to 24 h. The method was optimized for S. lactis LM0230, and transformation frequencies of between 1 x 104 and 5 x 105 transformants per ,Ig of purified plasmid (pMU1328) were achieved routinely. The optimized procedure involved lysozyme treatment of cells. Transformation of LM0230 occurred at comparable frequencies with pLSl (4.4 kilobase pair [kbpJ), pMU1328 (7.4 kbp), and pAM0l (26.5 kbp). Plasmid DNA isolated from transformants had not undergone detectable deletions or rearrangements. Transformation was possible with plasmid DNA which was religated after restriction endonuclease digestion. Phage DNA-dependent transfection of S. lactis LM0230 and S. lactis C6 was also achieved.

Lysogeny is widespread in the lactic acid bacteria. The majority of lysogens can be induced by UV irradiation or treatment with mitomycin C, but indicator strains which allow lytic growth of the induced phage are often not easy to identify. A few temperate phages have been shown to transduce chromosomal and/or plasmid markers. Information about the molecular biology of the temperate phages from lactic acid bacteria is sparse and needs significant supplementation in order that these potentially valuable phages might be utilized more efficiently as tools for improving existing starter strains in dairy fermentations.