Three outbreaks of foodborne botulism caused by unsafe home canning of vegetables--Ohio and Washington, 2008 and 2009

Foodborne botulism is a potentially fatal paralytic illness caused by ingestion of neurotoxin produced by the spore-forming bacterium Clostridium botulinum. Historically, home-canned vegetables have been the most common cause of botulism outbreaks in the United States. During 2008 and 2009, the Centers for Disease Control and Prevention (CDC) and state and local health departments in Ohio and Washington State investigated three outbreaks caused by unsafe home canning of vegetables. We analyzed CDC surveillance data for background on food vehicles that caused botulism outbreaks from 1999 to 2008. For the three outbreaks described, patients and their family members were interviewed and foods were collected. Laboratory testing of clinical and food samples was done at the respective state public health laboratories. From 1999 to 2008, 116 outbreaks of foodborne botulism were reported. Of the 48 outbreaks caused by home-prepared foods from the contiguous United States, 38% (18) were from home-canned vegetables. Three outbreaks of Type A botulism occurred in Ohio and Washington in September 2008, January 2009, and June 2009. Home-canned vegetables (green beans, green bean and carrot blend, and asparagus) served at family meals were confirmed as the source of each outbreak. In each instance, home canners did not follow canning instructions, did not use pressure cookers, ignored signs of food spoilage, and were unaware of the risk of botulism from consuming improperly preserved vegetables. Home-canned vegetables remain a leading cause of foodborne botulism. These outbreaks illustrate critical areas of concern in current home canning and food preparation knowledge and practices. Similar gaps were identified in a 2005 national survey of U.S. adults. Botulism prevention efforts should include targeted educational outreach to home canners.     

Bioactive phenolic compounds and functional properties of dehydrated bean flours

The impact of soaking, cooking, and industrial dehydration on the phenolic profile, antioxidant activity, and functional properties of two bean varieties (Cannellini and Pinta) was investigated. HPLC-PAC and HPLC-MS (ESI) analysis identified phenolic acids (44% and 41% of the total of identified phenolics, respectively) as the main phenolic compounds in raw Cannellini flour and catechins and procyanidins (63%) in raw Pinta flour. As a result of the industrial dehydration, a general reduction of these bioactive compounds and antioxidant activities (ORAC) was observed; however, their levels were still relevant in dehydrated bean flours. The raw and processed flours exhibited low oil holding capacity (1.00-1.15 mL/g), whereas water-holding capacities rose to 3.0-3.8 mL/g. Emulsifying activities and foaming capacities were inhibited during thermal processing. Thus, the significant occurrence of bioactive phenolic compounds, the relevant antioxidant capacities along with the interesting functional properties of dehydrated bean flours make them to be considered functional ingredients for food formulation.     

Protease B from Debaryomyces hansenii: purification and biochemical properties

The protease B (PrB; EC. 3.4.21.48) of Debaryomyces hansenii CECT 12487 was purified by selective fractionation with protamine sulfate followed by three chromatographic separations. The whole procedure resulted in 324-fold purification with a recovery yield of 1.0%. PrB was active at neutral-basic pH ranging from 6.0 to 12.0 with an optimum at pH 8.0. The molecular mass of the denatured enzyme was 30 kDa. Polyclonal-antibodies raised against PrB from Saccharomyces cerevisiae cross-reacted with the corresponding 30-kDa protein from D. hansenii. The serine protease inhibitor 3,4-DCI and sulphydryl group reagents markedly reduced the enzyme activity. The Km against N-succinyl-Leu-Tyr-7-amido-4-methylcoumarin was 1.79 mM. The presence of endogenous inhibitor for PrB was detected in cell-free extracts of D. hansenii although their inhibitory effect was lost after incubation at 25 degrees C for 20 h. PrB was able to hydrolyze muscle sarcoplasmic proteins by in vitro assays. This is the first endopeptidase purified and characterized from the yeast D. hansenii, whose possible contributions to meat fermentation processes are discussed.     

Antagonism of Gluconacetobacter diazotrophicus (a sugarcane endosymbiont) against Xanthomonas albilineans (pathogen) studied in alginate-immobilized sugarcane stalk tissues

Xanthomonas albilineans, a pathogenic bacterium that produces leaf scald disease of sugarcane, secretes a xanthan-like gum that invades both xylem and phloem of the host. Xanthan production has been verified after experimental infection of stalk segments of healthy plants. Moreover, Gluconacetobacter diazotrophicus is a nitrogen-fixing endosymbiont of sugarcane plants that antagonizes with X. albilineans by impeding the production of the bacterial gum. The physiological basis of this antagonism has been studied using tissues of sugarcane stalks previously inoculated with the endosymbiont, then immobilized in calcium alginate and maintained in a culture medium for Gluconacetobacter. Under these conditions, bacteria infecting immobilized tissues are able to secrete to the medium a lysozyme-like bacteriocin that inhibits the growth of X. albilineans.     

Production of bacteriocin-like inhibitory compounds by human fecal Bifidobacterium strains

Acid- and bile-resistant Bifidobacterium strains were isolated from human feces and identified by genus-specific PCR and randomly amplified polymorphic DNA PCR. Twenty-four different strains were screened for possible production of proteinaceous antimicrobial compounds by assaying the inhibitory effects of their neutralized culture supernatants. Six Bifidobacterium strains (BIR-0304, BIR-0307, BIR-0312, BIR-0324, BIR-0326, and BIR-0349) were selected on the basis of their broad inhibitory spectra. These strains were active against gram-positive and gram-negative bacteria and yeasts relevant to food safety and human health. The antagonistic effects of the six selected Bifidobacterium strains were related to bacteriocin-like compounds, which were active at pH values between 3 and 10, stable at 100 degrees C for 10 min, resistant to alpha-amylase and lipase A, but sensitive to proteinases (trypsin, proteinase K, protease A, pepsin, and cathepsin B). The molecular masses of the antimicrobial compounds produced by Bifidobacterium BIR-0312 and BIR-0324 were in the range of 10 to 30 kDa, and those of the compounds produced by Bifidobacterium BIR-0304, BIR-0307, BIR-0326, and BIR-0349 were less than 10 kDa. All Bifidobacterium strains produced maximum antimicrobial activities in the late logarithmic phase of growth and in the presence of Tween 80. These results confirm that the synthesis of bacteriocin-like inhibitory compounds is a key factor in the in vitro inhibition of pathogen and spoilage bacteria by Bifidobacterium strains.     

The potential role of concentrated solar power (CSP) in Africa and Europe—A dynamic assessment of technology development,cost development and life cycle inventories until 2050

Concentrated solar power (CSP) plants are one of several renewable energy technologies with significant potential to meet a part of future energy demand. An integrated technology assessment shows that CSP plants could play a promising role in Africa and Europe, helping to reach ambitious climate protection goals. Based on the analysis of driving forces and barriers, at first three future envisaged technology scenarios are developed. Depending on the underlying assumptions, an installed capacity of 120 GW_el, 405 GW_el or even 1,000 GW_el could be reached globally in 2050. In the latter case, CSP would then meet 13–15% of global electricity demand. Depending on these scenarios, cost reduction curves for North Africa and Europe are derived. The cost assessment conducted for two virtual sites in Algeria and in Spain shows a long-term reduction of electricity generating costs to figures between 4 and 6 ct/kWh_el in 2050. The paper concludes with an ecological analysis based on life cycle assessment. Although the greenhouse gas emissions of current (solar only operated) CSP systems show a good performance (31 g CO₂-equivalents/kWh_el) compared with advanced fossil-fired systems (130–900 CO₂-eq./kWh_el), they could further be reduced to 18 g CO₂-eq./kWh_el in 2050, including transmission from North Africa to Europe.     

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