Effect of washing and disinfecting containers on the microbiological quality of fresh milk sold in Bamako (Mali)

The present study aimed to improve the microbiological quality of the milk, from the cow’s udder to the selling point by container washing and disinfecting. The total counts (TC), Enterobacteriaceae counts (EBC) were used as quality indicators.The results showed a significant decrease of milk flora at the selling point, from 1.6 × 10⁷ ± 1.3 × 10⁷ (control) to 4.8 × 10⁵ ± 0,8 × 10⁷ (intervention) colony forming units per ml (cfu ml⁻¹) for TC and 1.2 × 10⁶ ± 1.1 × 10⁶ (control) to 0.9 × 10⁴ ± 1.1 × 10⁴ (intervention) cfu ml⁻¹ for EBC. The study suggests that in milk production area, besides udder infection and water quality, hygiene behaviour with respect to hand washing, container’s cleaning and disinfection are the key areas that remain of relevance to milk hygiene intervention.     

Application of spent grains to increase porosity in bricks

The dumping of spent grains is going to be more difficult because of the increasing number of cattle. That means new ways of dumping must be developed.The goal of the work was to test the technical properties of bricks produced with spent grains added to increase porosity.The flexural strength of the fired samples remained at 8.5 MPa; the air-dried samples exhibited a small increase in flexural strength. The shrinkage and true density were almost identical, while the raw density, capacity for water absorption and open porosity showed minor differences.In the large-scale experiment no problems were observed during the production. The bricks produced with spent grains possessed a comparable or higher strength, a higher porosity and a reduced density after firing than those from a standard production clay. Because of the lower sintering temperatures the fired clay product was more strongly sintered, exhibiting both greater strength and higher porosity.     

Design and analysis of a self-tuning feedback controller for the Internet

Active queue management (AQM) is an effective method used in Internet routers for congestion avoidance, and to achieve a tradeoff between link utilization and delay. The de facto standard, the random early detection (RED) AQM scheme, and most of its variants use average queue length as a congestion indicator to trigger packet dropping. This paper proposes a novel packet dropping scheme, called self-tuning proportional and integral RED (SPI-RED), as an extension of RED. SPI-RED is based on a self-tuning proportional and Integral feedback controller, which considers not only the average queue length at the current time point, but also the past queue lengths during a round-trip time to smooth the impact caused by short-lived traffic dynamics. Furthermore, we give theoretical analysis of the system stability and give guidelines for selection of feedback gains for the TCP/RED system to stabilize the average queue length at a desirable level. The proposed method can also be applied to the other variants of RED. Extensive simulations have been conducted with ns2. The simulation results have demonstrated that the proposed SPI-RED algorithm outperforms the existing AQM schemes in terms of drop probability and stability.     

Identification of genomic region associated with rice weevil resistance in sorghum [Sorghum bicolor (L.) Moench]

The rice weevil Sitophilus oryzae (L.) is an important pest of stored sorghum (Sorghum bicolor L. Moench). Quantitative trait loci (QTL) associated with rice weevil resistance was analyzed using a F₁₀ recombinant inbred line (RIL) population derived from the cross 654 (susceptible) × LTR108 (resistant). Grain weight losses (GWL), flour production (FP), and percentage kernels damaged (PKD) were evaluated across two trails. A total of 21 QTLs for GWL, FP, and PKD were identified. The phenotypic variation explained by individual QTL varied from 4.14% to 15.51%. Both parents contributed resistance alleles. Several main effect QTLs affecting GWL, FP, and PKD were mapped to the same regions on chromosome 2. The identification of genomic regions associated with rice weevil resistance will be useful to understand the resistance mechanism and improve rice weevil resistance of sorghum by marker-aided approaches.     

Validation of the sensitive and accurate quantitation of the fatty acid distribution in bovine milk

A method for the precise analysis of the complex mixture of fatty acids in milk has been developed and validated. The triacylglycerol of nonanoic acid was applied as the internal standard (ISTD) for absolute quantification. Milk lipids were extracted by miniaturised ultrasonication and methylated with trimethylsulfonium hydroxide. Resulting fatty acid methyl esters were determined by gas chromatography with flame ionisation detection giving excellent resolution, including separation of several 18:1 isomers. The low quantitation limit (0.01 mg mL⁻¹ milk) indicates that the sensitivity of the method is sufficient to quantify up to 50 fatty acids, from 4:0 to 23:0. Measurements of precision provided excellent results for different bovine milk samples of different fat content (coefficient of variance: 1.9% and 9.8% for intra- and interday precision, respectively). Recovery averaged 108 ± 3.5%. Evaluation of methods for determining the total fat content showed that gravimetry is no longer needed when using the ISTD.     

Controlled transglutaminase treatment in Edam cheese-making

Transglutaminase (TG) has been widely used in the dairy industry to increase product yield. However, it has not been used in the production of ripened cheeses because of the difficulty of controlling TG activity. It was observed that cross-linking of TG in ultrafiltration retentate could be controlled using a protein standardisation step. TG increased the cheese yield 4%, due to an increase in the moisture content of the cheeses. Traditionally, increased cheese moisture reduces hardness of cheese, but this was not observed in the cheese from TG-treated milk. Furthermore, the organoleptic properties of the TG-cheeses did not differ significantly from those of the control cheeses. No differences were observed in the protein profile of the whey fraction as a result of the TG treatment. The protein standardisation process thus makes it possible to use TG in the production of Edam cheese.     

Seasonal variation of aflatoxin M1 in raw milk from the Yangtze River Delta region of China

The objective of this study was to evaluate the occurrence of aflatoxin M₁ (AFM₁) in raw milk samples from 18 dairy farms in the Yangtze River Delta region during four different seasons. A total of 72 tank milk samples was collected with 18 samples for each season. Milk AFM₁ was detected using LC-MS/MS. The AFM₁ was detected in 43 milk samples (59.7%) ranging in concentration from 10 to 420 ng/L. The concentration of AFM₁ in raw milk was significantly higher during the winter (123 ng/L) than during other seasons (P < 0.05). There was no significant difference between the spring (29.1 ng/L), summer (31.9 ng/L), and autumn (31.6 ng/L) (P > 0.05) seasons. This indicates that raw milk collected during the winter is at high risk for AFM₁ and that seasonal factors should be considered for the management of aflatoxins in both the feed and milk.     

Evaluation of the absolute affinity of neuraminidase inhibitor using steered molecular dynamics simulations

The absolute free energy difference of binding (ΔG) between neuraminidase and its inhibitor was evaluated using fast pulling of ligand (FPL) method over steered molecular dynamics (SMD) simulations. The metric was computed through linear interaction approximation. Binding nature was described by free energy differences of electrostatic and van der Waals (vdW) interactions. The finding indicates that vdW metric is dominant over electrostatics in binding process. The computed values are in good agreement with experimental data with a correlation coefficient of R = 0.82 and error of σΔG_exp = 2.2 kcal/mol. The results were observed using Amber99SB-ILDN force field in comparison with CHARMM27 and GROMOS96 43a1 force fields. Obtained results may stimulate the search for an Influenza therapy.     

Real time loop-mediated isothermal amplification using a portable fluorescence scanner for rapid and simple detection of Vibrio parahaemolyticus

We evaluated the usefulness of the loop-mediated isothermal amplification (LAMP) using a portable ESE Quant tube scanner as a rapid and simple method for the detection of Vibrio parahaemolyticus, an important pathogen causing seafood-borne gastroenteritis. The real time LAMP (RT-LAMP) assay using a hemolysin gene (tlh/ldh)-specific primers was verified using V. parahaemolyticus strains (n = 91) from different countries and other non-target strains to check the utility of this method. Both the sensitivity and specificity of the RT-LAMP using 3 pairs of tlh/ldh-specific primers developed in this study were excellent (100%). The detection limit of the RT-LAMP was as low as 7 Colony forming unit per reaction and detection time was only 20 min. Comparative evaluation of the target bacterial strains with the RT-LAMP using ESE Quant tube scanner, API 20E system and conventional RT-PCR method revealed that the RT-LAMP assay developed in this study is simpler and more rapid than the latter two methods. Therefore, the RT-LAMP method using the easily portable ESE Quant tube scanner can be considered as an effective tool for the rapid screening of V. parahaemolyticus strains in environmental and clinical samples, especially, in remote areas of developing countries during epidemic periods.     

Monitoring the presence of residues of tetracyclines in baby food samples by HPLC-MS/MS

Tetracyclin is a group of antimicrobial permitted in animal food production, but their concentrations in food of animal origin should not exceed 100 μg kg⁻¹ (in meat and milk). Although the detection of these substances above these limits involves fines and jail for the producer, residues of tetracyclines are still being detected in food a potential risk to consumer health, especially babies.In the past, baby foods were carefully prepared at homes. However, modern lifestyles have led to the commercialization of ready-made baby food. Generally, these products are made with vegetable and meat from different animals, such as pork, chicken or beef. The presence of tetracyclines in meat at concentrations above 100 μg kg⁻¹ is forbidden in Europe by the Regulation 37/2010. Consequently this concentration is also applicable to the portion of meat present in baby food. Even if the presence of tetracyclines is controlled regularly in meat, they should also be monitored in baby food as babies are vulnerable to such as drugs.A rapid analytical method based on high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS) for quantification of four tetracyclines (tetracycline, chlortetracycline, doxycycline and oxytetracycline) in baby food is presented. The tetracyclines are extracted with EDTA-McIlvaine buffer, acidified at pH 4.0, followed by liquid–liquid extraction with ethyl acetate. The final extract is analysed within 19 min on a Sunfire HPLC column from Waters. Validation was performed according to the Commission Decision 2002/657/EC. The mean accuracy was 103 μg kg⁻¹, and the mean precision, was less than 23% for all the tetracyclines. The method was tested on 31 prepared baby food samples containing vegetable and beef. The presence of oxytetracycline was detected in one of the samples at a concentration of 5 μg kg⁻¹.