Combined analytical and microbiological tools to study the effect on Aspergillus flavus of cinnamon essential oil contained in food packaging

Cinnamon essential oil has been used for centuries to protect food from microbiological infection, and in the last ten years cinnamon essential oil is also incorporated into food packaging materials as antimicrobial agent. However, very little is known about the real effect that it has on the microorganism cells. This study combines analytical and microbiological tools to elucidate cell damage produced on Aspergillus flavus. First, antifungal activity of cinnamon essential oil was evaluated at 10³,10⁴, 10⁵ and 10⁶ CFU/mL. Minimal Inhibitory Concentration (MIC) and Minimal Fungicidal Concentration (MFC) were determined by macrodilution in direct contact with the mold. A strong activity was obtained, with a MIC of 0.05–0.1 mg/mL, and a MFC of 0.05–0.2 mg/mL, both ranges depending on the initial fungal suspensions.Polyethylene terephthalate films containing cinnamon essential oil were tested in vapor phase, without direct contact with the mold. Active PET started showing activity at 2% CIN EO load and produced total inhibition at 4% CIN EO. SEM and FTIR were used to study the cell damage on the mold exposed to the cinnamon essential oil. Evident damage and a strong decrease in sporulation were found by SEM, while biochemical changes in conidia could be suggested from the FTIR spectra analysis. Two deposition techniques were used to prepare the samples for FTIR. The results obtained are shown and discussed.     

Potential of botanicals and biocontrol agents on growth and aflatoxin production by Aspergillus flavus infecting rice grains

The potential of certain plant extracts and biocontrol agents for the reduction of aflatoxin B₁ (AFB1) in stored rice was investigated. Among the plant extracts tested, Syzigium aromaticum (5 g/kg) showed complete inhibition of Aspergillus flavus growth and AFB1 production. Curcuma longa, Allium sativum and Ocimum sanctum also effectively inhibited the A. flavus growth (65–78%) and AFB1 production (72.2–85.7%) at 5 g/kg concentration. Among the biocontrol agents, culture filtrate of Rhodococcus erythropolis completely inhibited the AFB1 production at 25 ml/kg concentration. The other biocontrol agents, Pseudomonas fluorescens, Trichoderma virens and Bacillus subtilis showed 93%, 80% and 68% reduction of A. flavus growth and 83.7%, 72.2% and 58% reduction of AFB1 at 200 ml/kg, respectively.     

Inhibition of non-toxigenic Aspergillus niger FS10 isolated from Chinese fermented soybean on growth and aflatoxin B1 production by Aspergillus flavus

A non-toxigenic strain FS10 was isolated from Chinese fermented soybean to control AFB₁ contamination and conformed as Aspergillus niger by 18S rDNA. To elucidate the biocontrol mechanism, the ability of culture filtrate of strain FS10 against growth and AFB₁ production by toxigenic Aspergillus flavus was evaluated in vitro. Meanwhile, the influence of filtrate on spore morphology of A. flavus was analyzed by optical microscope and atomic force microscope (AFM). Results demonstrated that the culture filtrate of FS10 significantly suppressed A. flavus growth, sporulation and AFB₁ biosynthesis. After 9 days, the inhibition of mycelia growth, sporulation and AFB₁ production reached to 37.7%, 100% and 94.5%, respectively. In addition, optical microscopy and AFM showed that the culture filtrate serious damaged spore morphology, accompanying with spore analysis and cell wall collapse, resulted in inhibition of spore germination. The degradation activity of FS10 culture filtrate on AFB₁ was also estimated. When AFB₁ was incubated with the culture filtrate, 85.8% of AFB₁ could be degraded after 5 days. It is concluded that the culture filtrate of strain FS10 has pleiotropic effects on control AFB₁ contamination. As a safe, effective and economic biological agent, the filtrate could be applied in fermented food to prevent toxigenic Aspergillus spp. and AFB₁ contamination.     

Inhibitory of multiple antifungal components produced by Lactobacillus plantarum K35 on growth,aflatoxin production and ultrastructure alterations of Aspergillus flavus and Aspergillus parasiticus

The antifungal activity of Lactobacillus plantarum K35 isolated from traditional Thai fermented rice noodle was evaluated against the growth and aflatoxin production of Aspergillus flavus TISTR304 and Aspergillus parasiticus TISTR3276. Multiple antifungal compounds secreted by L. plantarum were firstly analyzed using GC–MS in parallel to the ultrastructure alteration of the treated fungi. L. plantarum K35 supernatant caused significant reduction of the fungal growth and aflatoxin production. The antifungal activity was pH-dependent and favorable to acidic conditions whereas the catalase treatment had no influence indicating no involvement of hydrogen peroxide in the inhibition. Antifungal substances were resistant to sterilization and proteolytic enzymes including trypsin and proteinase K. The major components, apart from lactic acid, were 2-butyl-4-hexyloctahydro-1H-indene (19.55%), oleic acid (10.52%) and palmitic acid (7.27%). Other minor antifungal compounds included linoleic acid (2.11%), 2,4-di-tert-butylphenol (1.84%), stearic acid (1.55%), 3-phenyllactic acid (1.42%) and pyroglutamic acid (1.07%). The morphological changes of the fungi exposed to the supernatant were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). L. plantarum K35 supernatant caused severe damage to the cell wall and cytoplasmic membrane leading to a massive loss of cytoplasmic content, the formation of membrane-bound vesicles, and complete destruction of membranous organelles including mitochondria and nucleus.     

Aflatoxin production by Aspergillus flavus in rumen liquor and its implications

Cow milk in infant and human nutrition is very significant. However, contamination of milk with aflatoxins is considered as a potential risk for human health. Aflatoxin is one of the major etiological factors in the development of hepatocellular carcinoma and is also found in the milk of lactating animals which could have consumed it through contaminated feedstuffs. Thus, exploration to isolate and identify the pathogenic microbe present in the rumen liquor were carried out. The screened fungal organism was identified as Aspergillus flavus by phenotypic (morphology and extrolite profiles) and molecular (β-tubulin gene sequences) characters. Fungal toxin was extracted using immuno-affinity column (IAC) and quantified by High Performance Liquid Chromatography (HPLC). The organism had potential to grow under aerobic and anaerobic conditions and also produce aflatoxin B_1. The aflatoxin B₁ production under aerobic condition was 0.902 ± 0.08 μg/ml culture broth and anaerobic condition was 0.925 ± 0.2 μg/ml culture broth. Aflatoxin B₂ was more compared to aflatoxin B₁ and the quantity was 14.472 ± 1 under aerobic condition and 1.467 ± 0.3 under anaerobic condition. The rumen liquor from which the isolation was carried out also showed the presence of aflatoxin B₁ (3.964 ± 0.5 μg/ml) and B₂ (1.170 ± 0.6 μg/ml). However, aflatoxin G₁ and G₂ were not present. Hence, the study suggests the ability of microbial ecosystem present inside the rumen to produce aflatoxin. This report on the aflatoxin production under aerobic and anaerobic conditions provides insights about the possibility of aflatoxin in cow milk thereby effecting human health. It is vital to reduce exposure of milking animals to contaminated moldy feed and take precautions to prevent fungal contaminations in the feed.     

Upland rice vinegar vapor inhibits spore germination,hyphal growth and aflatoxin formation in Aspergillus flavus on maize grains

The efficacy of vapor-phase (VP) upland rice vinegar (URV) was investigated as a bio-fumigant for maize, to reduce consumer health risks associated with spore and toxin formation by Aspergillus flavus. Complete reduction of mycelial growth occurred with in vitro VP exposure to URV (containing 0.0017 mmol/L acetic acid) or with VP exposure to pure acetic acid (PAA) (containing 0.0023 mmol/L acetic acid). No significant differences were observed between the two materials after 90 min exposures. Using gas chromatography-mass spectrometry (GC-MS), URV vapor was shown to contain volatiles having antifungal activities. These are identified as isoamylalcohol, 1-butanol, 3-methyl-, acetate and β-phenylethyl acetate. It is suggested these volatiles increase the antifungal effectiveness of URV. Exposure to VP-URV (containing 0.0043 mmol/L AA) for 5 h completely eliminated viable spores of A. flavus on maize seeds (23% moisture content) previously inoculated with 4.43 ± 0.28 log spores/g). At the same time, aflatoxin production decreased, as VP-URV exposure increased. Hence, VP-URV is shown to be an effective control agent for A. flavus mycelial growth and aflatoxin formation on maize, so effectively reducing the potential for consumer health risks due to this widespread fungus.     

Effect of water activity and temperature on the growth of Aspergillus flavus,the expression of aflatoxin biosynthetic genes and aflatoxin production in shelled peanuts

The contamination of peanuts with Aspergillus flavus and subsequent aflatoxins is considered to be one of the most serious safety problems in the world. Water activity (a_w) and temperature are limiting factors for fungal growth and aflatoxins production during storage. To optimize the practical storage parameter, the effect of a_w (0.85–0.99) and temperature (15–42 °C) on fungal growth, aflatoxin production and the expression of aflatoxin biosynthetic and regulatory genes in shelled peanuts was investigated. A. flavus grew at a lower rate when temperature ≤20 °C or a_w ≤ 0.85. For the growth of A. flavus in shelled peanuts, the optimum conditions were a_w was 0.98, and the optimum temperature was 37 °C. The maximum amount of AFB₁ in peanuts was obtained at 28 °C and a_w 0.96. Real-time analysis showed that 16 of 25 genes had highest expression levels at 28 °C under a_w 0.92, while 9 genes had highest expression levels at 37 °C under a_w 0.92. Compared with 37 °C, all aflatoxin biosynthetic pathway genes were down-regulated at 42 °C. All the pathway genes and laeA were up-expressed at a_w of 0.96 under 28 °C, compared to a_w 0.99. Furthermore, there was a good positive correlation between the ratio of aflS/aflR and AFB₁ production. The expression of laeA was also positively correlated with AFB₁ production while the expression of brlA was correlated with the A. flavus growth. The results of this study suggest that AFB₁ production in peanut kernels can occur over a wider range of a_w × temperatures levels compared to formula media and peanut media. Previous studies have showed that AFB₁ could not be produced on formula media at 37 °C without the expression of most aflatoxin structural genes. But, in the un-autoclaved shelled peanuts, high concentration of AFB₁ was produced at 37 °C with up-regulation of some aflatoxin biosynthetic genes. From a food safety point of view, the results can be used to optimize certain food technological processes and develop prevention strategies to control such carcinogenic natural metabolites in grains (such as peanuts, maize and rice) and derived products.     

Comparative study of the simultaneous action of three essential oils on Aspergillus flavus and Sitophilus zeamais Motsch

Maize is among the most important produced and consumed crops in Cameroon. However, the availability of this cereal is limited by post-harvest losses, especially in the course of storage. Therefore, there is an urgent need to overcome this phenomenon through the use of efficient, cheap methods. To this effect, the simultaneous action of three essential oils, obtained by hydrodistillation from leaves of Ocimum gratissimum and Lippia rugosa and fruits of Xylopia aethiopica, on Aspergillus flavus and Sitophilus zeamais was investigated using a 2⁴ factorial design. The three essential oils and the storage time were considered as factors. The results revealed that low volume (60 μl/200 g grain) for O. gratissimum and high volume for L. rugosa (310 μl/200 g grain) and X. aethiopica (250 μl/200 g grain) showed the most important efficiencies against A. flavus and S. zeamais in a 2 weeks storage. Hence, the rate of mortality for S. zeamais was 92% and 89%, respectively, in samples of maize infested by S. zeamais and samples of maize infested by S. zeamais and A. flavus. Ninety five percent of A. flavus conidia were inhibited in samples of maize infested by A. flavus and samples of maize infested by S. zeamais and A. flavus.     

Influence of emulsifier type on the antifungal activity of cinnamon leaf,lemon and bergamot oil nanoemulsions against Aspergillus niger

Only exiguous data are currently available on the antifungal properties of essential oil (EO) nanoemulsions against spore-forming microorganisms. The aim of this work is to develop physically stable nanoemulsion-based delivery systems for different EOs (cinnamon leaf, lemon, and bergamot), to exploit their antifungal properties against Aspergillus niger. The inhibition of mycelial radial growth and spore germination were used as indicators of antifungal activity of the nanoemulsions, which were prepared at 3 wt% EO, using non-ionic Tween 80 (T80) or anionic whey protein isolate (WPI) (1 wt%) as emulsifiers, and sunflower oil (1 wt%) as ripening inhibitor. The nanoemulsions were physically stable over seven days of accelerated aging at 35 °C.The minimal inhibitory concentration of free cinnamon leaf and of both citrus EOs were 0.35 and 5.50 μg/g, respectively. The encapsulation of cinnamon leaf EO in nanoemulsions significantly enhanced the inhibiting effect against A. niger mycelial growth and spore germination, with respect to the free EO. In contrast, for citrus EOs, the encapsulation in nanoemulsions generally decreased the antifungal activity, likely because of the nanoemulsion acting as a hydrophobic sink for the main constituents of citrus EOs. The emulsifier played a fundamental role in the resulting antifungal activity, with WPI-based nanoemulsions being more effective in inhibiting the mycelial growth and the spore germination of A. niger than T80-based ones. The antifungal action was correlated to the morphological alterations observed in A. niger, such as the loss of cytoplasm in fungal hyphae and hyphal tip. The results of this study show the importance of nanoemulsions design in the development of efficient and stable natural antifungal agents for food applications.     

Adsorption of sodium dodecyl sulfate, Triton X100 and their mixtures to shale and sandstone: A comparative study

In this paper, batch experiments of sediment/aqueous systems were conducted to evaluate the adsorption of SDS, TX100 and their mixtures (1:2; 1:1 and 2:1 SDS:TX100 mass ratio) onto local shale and sandstone. Adsorption of surfactants was assessed using a surface tension technique for surfactant concentrations less than surfactant monomer saturation (CMC). It is shown that the amount of TX100 adsorbed to shale (7.5 g/kg) are greater than those adsorbed to sandstone (1.5 g/kg). SDS showed negligible affinity for adsorption on both adsorbents. The amounts of both TX100 adsorbed to shale or sandstone can be decreased and minimized when they are mixed with SDS. While adsorption of TX100–SDS mixtures on shale reduced to 4.5 g/kg (40% reduction in comparison to adsorption of TX100), adsorption to sandstone decreased tremendously to 0.3 g/kg (80% reduction in comparison to adsorption of TX100). Furthermore, micellization behavior was assisted through mixing. CMCs of mixtures reduced to 0.1 wt.% in presence of shale compared to 0.15 wt.% for TX100 and 0.1 wt.% for SDS. Similarly, CMC of mixtures reduced to 0.03 wt.% in presence of sandstone in comparison to 0.05 for pure TX100 and 0.1 wt.% for SDS. Because of their ability to minimize amounts adsorbed in different adsorbents, mixed anionic–nonionic surfactant particularly TX100–SDS may show potential advantages in SEAR and EOR applications.     

Antifungal activity of Michelia alba oil in the vapor phase and the synergistic effect of major essential oil components against Aspergillus flavus on brown rice

The objectives of this study were to investigate the effect of essential oil (Michelia alba) vapor on the spore germination and mycelium growth of Aspergillus flavus on brown rice and to perceive the shelf life of the brown rice could be extended to a longer storage time. Different volumes (150, 300, 450 μl) of M. alba and a 300 μl linalool/caryophyllene combination at ratios of 10:1, 1:1, and 1:10 were first absorbed into plant absorbent material (Φ∼20 mm) before being put into a closed glass box (1L) containing A. flavus spore and the mycelium (Φ∼5 mm) in a Malt Extract Agar (uncovered plate). Mold testing was also carried out on brown rice with A. flavus spore suspension before being incubated at 25° C and 100% RH for 16 weeks. Quality tests e.g. texture, a sensorial evaluation (hedonic scale) of brown rice were also conducted. Results indicated that the vapor phase of M. alba at ≥ 300 μl L⁻¹ air could inhibit both spore germination and A. flavus mycelium. Antifungal activity of M. alba in air was strongly correlated with the linalool/caryophyllene combination at the ratio of 10:1 in 300 μl L⁻¹ air. In addition, M. alba vapor at 300 μl L⁻¹ air was found to extend the shelf-life of the brown rice by four times (16 weeks) in comparison with the control treated without essential oil (4 weeks). After being cooked, the hardness of brown rice with volatile essential oil was found to be reduced by one third (compared to the control brown rice). The hedonic value (overall liking) of cooked brown rice packed with M. alba vapor at 300 μl for 1 week and then stored for 16 weeks was a 7, rated as “like moderately”. Therefore, this study has demonstrated the good potential of M. alba vapor to control mold growth on the surface of brown rice.     

Application of experimental design and response surface methodology to optimize the procedure to obtain a bactericide and highly antioxidant aqueous extract from orange peels

In recent years there is a growing demand for healthy and safe food, without added preservatives or synthetic antioxidants. In this regard, plant extracts have promising future due to their high contents of bioactive compounds, especially in phenolic and polyphenolic compounds that exhibit antimicrobial and antioxidant activities. For this reason, the plant extracts could form the basis of many applications, including the preservation of fresh and processed foods. In this work, the methodology to obtain orange peel extracts with high bioactive properties is presented. To adjust the extraction conditions, experimental design and response surface methodology were applied to establish the optimum value of all the experimental variables that have influence in the extraction system. Total phenolic contents and antioxidant activity values were used as response parameter. The peel extracts, obtained with the proposed methodology, exhibited a high content of phenolic compounds, high antioxidant and antimicrobial activity, against Escherichia coli and Listeria innocua (in-vitro experiments). Finally, to demonstrate the feasibility of the peel extracts, they were used as natural additive in apple juice reducing significantly juice browning and the microbial load for both bacteria.     

In vitro control of growth and ochratoxin A production by butylated hydroxyanisole in Aspergillus section Nigri species

This study was carried out to determine the efficacy of phenolic antioxidant butylated hydroxyanisole (BHA) under different interacting water activity (a_W) and temperature regimes on the lag phase and growth rate by Aspergillus section Nigri strains. In this experiment four A. section Nigri strains were used. Peanut meal extract agar (PMEA) was prepared at 2%. The a_W of the medium was adjusted to 0.995, 0.980 and 0.930, BHA at 1, 5, 10 and 20 mmol l^?1 was added to the basic medium. The plates were inoculated and incubated for 30 days at 18 and 25 °C. Radial growth rates (mm d^?1) and lag phase (h) were calculated. In control treatments, the growth rate decreased as water activity reduced in all strains assayed. At all a_W levels tested, BHA at 20 mmol l^?1 completely inhibited growth. In general, at 10 mmol l^?1 and 0.995 and 0.980a_W level, a significant reduction respect to control was observed. This antioxidant completely inhibited OTA production, at concentrations of 20 mmol l^?1, regardless of a_W used by all the strains evaluated.     

Biological activities of Boswellia sacra extracts on the growth and aflatoxins secretion of two aflatoxigenic species of Aspergillus species

Aflatoxins are the most serious carcinogenic, hepatotoxic, teratogenic and mutagenic secondary metabolites which adversely affect human and animal health. This study was designed to evaluate the in vitro inhibitory effect of different concentrations of Boswellia sacra resin (2.5, 5, 7.5 and 10 g/100 ml), leaf extract (5, 7.5, 10, 12.5 and 15 ml/100 ml), and essential oil (1, 2, 3, and 4 ml/100 ml) on the growth and aflatoxins production by two species of Aspergilli, namely Aspergillus flavus (SQU21) and Aspergillus parasiticus (CBS921.7). Resin of B. sacra caused 57.9–92.1% inhibition of aflatoxin secretion by A. flavus and 43.6–95.7% for A. parasiticus. However, the mycelial dry weights were significantly increased by 20.9–52.7% for A. flavus, and 8.9–68.5% for A. parasiticus. The leaf extract of B. sacra apparently enhanced aflatoxins production by 20–50%, and mycelial dry weight by 25.5–29.1% for A. flavus and A. parasiticus. The essential oil of B. sacra at different concentrations similarly inhibited the fungal growth and aflatoxins production by 45.8–83.7% for A. flavus and 41.3–83.5% for A. parasiticus which indicates the antifungal activity of this oil. None of the B. sacra extracts detoxified pure aqueous aflatoxin B₁. We have concluded that B. sacra resin and essential oil possess biological activity against biochemical synthesis and metabolic pathway of aflatoxin production of the two Aspergillus species. Therefore, the resin and essential oil of B. sacra can be recommended as safe plant based bioreservatives to enhance shelf life of food and feed products with reference to adverse effect of physical and synthetic chemical preservatives and their antimicrobial and aflatoxins inhibition activity.     

Desirability of adding mixtures of phenols and amine antioxidants to mineral oils

Studies have been made on the effectiveness of amine and phenolic inhibitors, including mixtures of them, in MS-8 mineral oil under conditions of high-temperature catalytic oxidation. It is found that mineral oils containing simultaneously amine and phenolic inhibitors have oxidation rates that are determined only by the content of the amine inhibitor, while the phenolic inhibitor partially determines the secondary oxidation-destruction processes. Translated from Khimiya i Tekhnologiya Topliv i Masel, No.3, pp.45 – 47, May – June, 2009.     

油气重力异常提取的灰色方法研究

本文根据灰色预测理论,应用四阶GM模型来模拟反映构造和基底变化的重力区域场,从而获得重力剩余场。分析表明,用该灰色方法计算所得的新疆塔里木盆地北部托库测区剩余重力场可解释为油气微重力异常。     

Kinetic of sodium silicate dissolution when subjected to mechanical and hydrocoustic action

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 18–20, March, 1992.     

Antimicrobial efficacy of grape seed extract against Escherichia coli O157:H7 growth,motility and Shiga toxin production

Escherichia coli O157:H7 produces Shiga toxin (Stx) which is heat stable and causes Hemolytic Uremic Syndrome (HUS), a serious disease associated with bloody diarrhea and even death. To ensure food safety, both live E. coli O157:H7 and its toxin production in food products need to be controlled. Natural ingredients with inhibitory effects on E. coli O157:H7 growth and toxin production are top choices of antimicrobials for the food industry. The objectives of this study were to evaluate efficacy of grape seed extract (GSE) against the growth, swimming motility and Stx production of E. coli O157:H7. The disc diffusion assay indicated that 3.2 mg GSE per disc resulted in an inhibition zone of 14.8 ± 0.21 mm. The minimal inhibitory concentration of GSE against E. coli O157: H7 was 4.0 mg/ml. At high inoculation level (1 × 10⁷ CFU/ml), including GSE at 0.25–2.0 mg/ml reduced Stx production without inhibiting E. coli O157:H7 growth. At 5 × 10⁵ CFU/ml inoculation level, 2.0 and 4.0 mg/ml GSE effectively inhibited the growth of E. coli O157:H7 for at least 72 h, however, a low level of GSE (0.125–1.0 mg/ml) enhanced E. coli O157:H7 growth and Stx2 production. At 4 mg/ml, GSE completely abolished Stx2 production in addition to it bactericidal effect against E. coli O157:H7. In addition, GSE at concentration as low as 0.125% blocked the swimming motility, which is important for E. coli O157:H7 surface adherence. In conclusion, GSE is effective in inhibiting the motility of E. coli O157:H7, GSE shows potential to be used as a natural antimicrobial to control E. coli O157:H7.     

Pulsed electric field inactivation of E. coli O157:H7 and non-pathogenic surrogate E. coli in strawberry juice as influenced by sodium benzoate,potassium sorbate,and citric acid

Current FDA regulations require that juice processors achieve a 5 log CFU/ml reduction of a target pathogen prior to distributing products. Whereas thermal pasteurization reduces the sensory characteristics of juice, pulsed electric field (PEF) treatments can be conducted at lower temperatures and may preserve sensory characteristics.Escherichia coli O157:H7 (ATCC 43895) and a non-pathogenic E. coli (ATCC 35218), respectively, were inoculated into single-strength strawberry juice with or without 750 ppm sodium benzoate (SB), 350 ppm potassium sorbate (PS), and 2.7% citric acid (CA). Juice was treated at outlet temperatures of 45, 50 and 55 °C at a field strength of 18.6 kV/cm for 150 μs with a laboratory-scale PEF unit. Inactivation of surrogate E. coli at 45, 50, and 55 °C were 2.86, 3.12, and 3.79 log CFU/ml, respectively, in plain juice (pH 3.4), and 2.75, 3.52, and 5.11 with the addition of benzoic and sorbic acids (pH 3.5). Inactivation of E. coli O157:H7 under the same conditions were 3.09, 4.08, and 4.71 log CFU/ml, respectively, and 2.27, 3.29, and 5.40 with antimicrobials. E. coli O157:H7 in juice with antimicrobials and 2.7% CA (pH 2.7) treated with PEF was reduced by 2.60, 4.32 and 6.95 log CFU/ml at 45, 50 and 55 °C while the surrogate E. coli decreased by 3.54, 5.69, and 7.13 log under the same conditions. When juice (pH 2.7) was held for 6 h without PEF treatment, higher numbers of E. coli 35218 (7.17 log CFU/ml) were inactivated than of acid-resistant E. coli O157:H7 (3.89 log). Slightly greater PEF inactivation of E. coli O157:H7 than of the surrogate bacterium indicates that E. coli ATCC 35218 provides a margin of safety when used as a surrogate for O157:H7 in plain strawberry juice or in juice + SB + PS at 45–50 °C, or with SB + PS and CA at 55 °C.     

China,US and Spain to drive wind energy growth

General Motors Corp. will sell its first gas-electric hybrid cars in China in July, introducing a model created in part by GM＇s Shanghai design center. The Buick LaCrosse will be the second hybrid to enter the Chinese automobile market following Toyota Motor Corp＇s Prius in early 2006. The LaCrosse will be priced under 300,000 yuan （$43,000） - comparable to the Prius. The car was developed with contributions from GM＇s Pan Asia Technical Automotive Center in Shanghai. Hybrids improve fuel efficiency and cut emissions by generating extra power from the brakes as a vehicle tops. But they also cost more because they require both gasoline and electric motors.