Culture media for non-sporulating gram-positive food spoilage bacteria

Draft Genome Sequence of the Psychrotolerant Bacterium Kurthia sibirica ATCC 49154 T

The aerobic, Gram-positive, psychrotolerant bacterium Kurthia sibirica was first isolated from the stomach and intestinal contents of the Magadan mammoth recovered from the permafrost in eastern Siberia in 1977. K. sibirica was sequenced, and the predicted genome size is 3,496,665 bp, with 36.42% G+C content.

The aerobic, Gram-positive, psychrotolerant bacterium Kurthia sibirica was first isolated from the stomach and intestinal contents of the Magadan mammoth recovered from the permafrost in eastern Siberia in 1977. K. sibirica was sequenced, and the predicted genome size is 3,496,665 bp, with 36.42% G+C content.

Genome Sequence of Kurthia Type Species Kurthia zopfii Strain ATCC 33403 T

The genome of the type strain of the Kurthia genus, Kurthia zopfii ATCC 33403, was sequenced. Nonpathogenic K. zopfii has been isolated from intestinal contents, fecal material, meats, meat products, milk, water, and air, including air at high altitudes.

The genome of the type strain of the Kurthia genus, Kurthia zopfii ATCC 33403, was sequenced. Nonpathogenic K. zopfii has been isolated from intestinal contents, fecal material, meats, meat products, milk, water, and air, including air at high altitudes. The predicted genome size is 2,878,279 bp, with 37.05% G+C content.

Microbial community assessment of mealworm larvae (Tenebrio molitor) and grasshoppers (Locusta migratoria migratorioides) sold for human consumption

In Western countries, the popularity of edible insects as an alternative animal protein source is increasing. Nevertheless, there is a lack of profound insight into the microbial safety and shelf life of living insects sold for human consumption. The purpose of this study was to characterise the microflora of fresh edible mealworm larvae and grasshoppers in a quantitative and qualitative way. Therefore, culture-dependent analyses (the total viable aerobic count, Enterobacteriaceae, lactic acid bacteria, yeasts and moulds, and bacterial endospores) and next-generation sequencing (454amplicon pyrosequencing) were performed. High microbial counts were obtained for both insect species. Different insect batches resulted in quite similar microbial numbers, except for bacterial endospores. However, the bacterial community composition differed between both insect species. The most abundant operational taxonomic unit in mealworm larvae was Propionibacterium. Also members of the genera Haemophilus, Staphylococcus and Clostridium were found. Grasshoppers were mainly dominated by Weissella, Lactococcus and Yersinia/Rahnella. Overall, a variety of potential spoilage bacteria and food pathogens were characterised. The results of this study suggest that a processing step with a microbiocidal effect is required to avoid or minimize risks involved with the consumption of edible insects.

Isolation of Kurthia gibsonii from non-gonorrheal urethritis: implications for the pathomechanism upon surveying the literature

The incidence and number of species involved in the spectrum of sexually transmitted infections continue to increase. Laboratories have to be prepared for identification of unusual microbes. In our practice, a male patient had recurring urethritis and balanitis after having repeated unprotected insertive sexual intercourse with female piglets. He also had allergy to scents and some metals, otherwise he showed no general symptoms. Specimens were swabbed from the urethra, inflamed glans, rectum, mouth onto several culture media, subsequently isolates were tested for their morphology, biochemical activity. Kurthia gibsonii was isolated from urethra and glans. No concomitant infection with other microbes was detected, haemoculture was negative. Relying upon antibiotic sensitivity test, he was cured with 2 × 500 mg oral cefuroxime for 15 days, and topical gentamycin cream for 2 months. This is the first reported sexually transmitted, zoonotic infection without generalization by Kurthia spp. We report first the antibiogram of K. gibsonii. Slight differences in the antibiotic sensitivity suggest independent infection and sensitivity of urethral and mucous membrane tissues to distinct K. gibsonii strains. Allergy of the patient might predispose to opportunistic infection. Such aspects ought to be tested in details in further cases.

Carnobacterium maltaromaticum: identification, isolation tools, ecology and technological aspects in dairy products

Carnobacterium species constitute a genus of Lactic Acid Bacteria (LAB) present in different ecological niches. The aim of this article is to summarize the knowledge about Carnobacterium maltaromaticum species at different microbiological levels such as taxonomy, isolation and identification, ecology, technological aspects and safety in dairy products. Works published during the last decade concerning C. maltaromaticum have shown that this non-starter LAB (NSLAB) could present major interests in dairy product technology. Four reasons can be mentioned: i) it can grow in milk during the ripening period with no competition with starter LAB, ii) this species synthesizes different flavouring compounds e.g., 3-methylbutanal, iii) it can inhibit the growth of foodborne pathogens as Listeria monocytogenes due to its ability to produce bacteriocins, iv) it has never been reported to be involved in human diseases as no cases of human infection have been directly linked to the consumption of dairy products containing this species.

Effects of temperature and pH on the growth of bacteria isolated from blown packs of vacuum-packaged beef

Bacteria recovered from the microflora of blown packs of vacuum-packaged beef were identified as Leuconostoc mesenteroides, Lactococcus lactis, Carnobacterium maltaromaticum, and Clostridium estertheticum, with L. mesenteroides predominant. Isolates of these lactic acid bacteria all grew in peptone yeast extract glucose starch broth (PYGSB) at temperatures between -2 and 30 degrees C but generally grew more slowly and over a more restricted temperature range in meat juice medium (MJM). A C. estertheticum isolate and the type strain of C. estertheticum subsp. estertheticum (ATCC 51377) both grew in PYGSB and MJM at similar rates at temperatures between -2 and 17 degrees C and grew at 20 degrees C in MJM but not in PYGSB. Square root models of the variation of the growth rate with temperature indicated that the C. maltaromaticum isolate and the C. estertheticum strains grew at similar rates that were faster than those of the other isolates at temperatures between -2 and 0 degrees C. The L. mesenteroides and L. lactis isolates grew in PYGSB at pH 5.0, but the C. maltaromaticum isolate and both strains of C. estertheticum did not grow in PYGSB at pH <or= 5.3. C. estertheticum stopped growing in MJM buffered at pH 6.5 when glucose was exhausted, although these bacteria then utilized lactate. The findings suggest that, like carnobacteria, C. estertheticum may predominate during the early stages of development of the spoilage microflora of vacuum-packaged beef but that C. estertheticum will likely be inhibited by a falling pH and so may be only a minor part of the spoilage microflora when maximum numbers are attained.

Short communication: Carnobacterium maltaromaticum: the only Carnobacterium species in French ripened soft cheeses as revealed by polymerase chain reaction detection

The PCR technique using Cb1-Cb2R and species-specific primers was applied to various French soft flowered or washed rind cheeses to identify Carnobacterium species. Thirty cheeses made from cow's, ewe's, or goat's milk (raw or pasteurized), of which 20 were Appellation d'Origine Contrôlée, were analyzed in the autumn and spring. The results revealed that, irrespective of the season, the Carnobacterium genus was initially detected in 5 cheeses and was detected in 5 others after an enrichment period. Polymerase chain reaction results using species-specific primers of Carnobacterium showed that these 10 cheeses contained only the species Carnobacterium maltaromaticum. Six different patterns of fermentation were found, and 3 of the 10 cheeses contained C. maltaromaticum isolates with anti-Listeria activity.

A selective enumeration medium for Carnobacterium maltaromaticum

A selective medium was proposed for isolating the species Carnobacterium maltaromaticum from cheeses. This medium, named CM, was elaborated using combinations of three antibiotics (gentamicin, nalidixic acid, vancomycin) and alkaline pH value (8.8). An experimental design (Doehlert matrix) was drawn up to optimize the experimental conditions of the preparation of the medium. Based on the TS-YE agar medium, it contained 3.5 mg L(-1) of vancomycin, 5.0 mg L(-1) of gentamicin, and 20 mg L(-1) of nalidixic acid. The incubation time was 36 to 48 h at 25 degrees C. The selectivity of this medium was tested against bacterial strains present in the dairy industry and controlled by the PCR method. Thanks to this medium, it was easy to detect C. maltaromaticum and to follow this species in the cheese-making process.

Cresol red thallium acetate sucrose inulin (CTSI) agar for the selective recovery of Carnobacterium spp

Carnobacterium spp. are commonly isolated from a variety of foods, especially from meats stored under anaerobic atmospheres at refrigeration temperatures, but the role of these organisms in the spoilage of meat and meat products is yet to be determined. Cresol Red Thallium Acetate Sucrose (CTAS) agar was developed as a selective medium for enumeration of carnobacteria, however problems such as poor recovery of Carnobacterium spp. and interference by other microorganisms have precluded its general use. The aim of this study was to improve CTAS agar by broadening its spectrum of selective recovery for carnobacteria while restricting the ability of interfering species to grow. Ten Carnobacterium spp. (five ATCC cultures and five isolates from fresh pork) and 20 other genera were used in testing the agar. A wider range of Carnobacterium spp. recovery was obtained by modifying concentrations of sucrose, manganese sulphate and thallium acetate. Additions of inulin and thiamine hydrochloride also improved growth response. The additions of vancomycin and Chrisin (nisin) eliminated interference from other microorganisms. A two-temperature incubation procedure was included to improve the characteristic growth of Carnobacterium spp. on the modified medium, identified as Cresol Red Thallium Sucrose Inulin (CTSI) agar. Lactic acid bacteria and Enterobacteriaceae were unable to grow on CTSI incubated aerobically. Growth of Carnobacterium spp. on CTSI yielded pink colonies, except for Cb. mobile, which formed gray colonies. In some instances, a red precipitate formed in the center of the colony. Yellowing and clearing of the growth medium was also frequently observed. Recovery of carnobacteria using CTSI was identical to that obtained with All Purpose Tween (APT) agar.

Identification of lactic acid bacteria from chili bo, a Malaysian food ingredient

Ninety-two strains of lactic acid bacteria (LAB) were isolated from a Malaysian food ingredient, chili bo, stored for up to 25 days at 28 degreesC with no benzoic acid (product A) or with 7,000 mg of benzoic acid kg-1 (product B). The strains were divided into eight groups by traditional phenotypic tests. A total of 43 strains were selected for comparison of their sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) whole-cell protein patterns with a SDS-PAGE database of LAB. Isolates from product A were identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus farciminis, Pediococcus acidilactici, Enterococcus faecalis, and Weissella confusa. Five strains belonging to clusters which could not be allocated to existing species by SDS-PAGE were further identified by 16S rRNA sequence comparison. One strain was distantly related to the Lactobacillus casei/Pediococcus group. Two strains were related to Weissella at the genus or species level. Two other strains did not belong to any previously described 16S rRNA group of LAB and occupied an intermediate position between the L. casei/Pediococcus group and the Weissella group and species of Carnobacterium. The latter two strains belong to the cluster of LAB that predominated in product B. The incidence of new species and subspecies of LAB in chili bo indicate the high probability of isolation of new LAB from certain Southeast Asian foods. None of the isolates exhibited bacteriocin activity against L. plantarum ATCC 14917 and LMG 17682.

Influence of unsliced delicatessen meat freshness upon bacterial growth in subsequently prepared vacuum packed slices

Unsliced beef pastrami, reformulated ham and bologna held at 6 degrees C were sliced 21, 17, 12 or 7 days before or at the assigned manufacturer's best before date and vacuum packaged. Packages of sliced meats were held at 6 degrees C for another 7, 12, 17 or 21 days, opened and analyses made for total bacteria, lactic acid bacteria, Enterobacteriaceae and Brochothrix thermosphacta. The maximum storage interval was 42 days; half this period unsliced, the remainder as repacked slices. Numbers of bacteria on pastrami were significantly greater than on ham and bologna (pastrami > ham > bologna) with the lactic acid bacteria dominating in all products. As unsliced meats approached their best before date, insignificant increases were generally noted for numbers of lactic bacteria, Enterobacteriaceae and B. thermosphacta. During subsequent storage of slices under vacuum, numbers of total and lactic bacteria increased exponentially at the same rate while B. thermosphacta growth was significantly slower. Numbers of Enterobacteriaceae remained low and were essentially unchanged during sliced meat storage. Within the context of study storage parameters, shelf-life appeared to be determined by length of time after slicing and repackaging rather than by best before date of the unsliced meat. Packages of sliced meat prepared from wholesale unsliced meats with 21 days left until their best before date or from unsliced meats with 12 days left until the best before date showed similar bacterial levels 21 days later. It was probable that the localization of bacterial growth at the meat surface-packaging film interface of the unsliced meats yielded slices with initially lowered bacterial content when repackaged and sampled from the uppermost slice. When Enterobacteriaceae and B. thermosphacta were absent from unsliced meats, extension of sliced meat package shelf-life beyond the best before date of the parent meat was possible. However, these bacterial groups were not always undetected.