A procedure for the sensory analysis of gas chromatographic effluents

A method is presented for determining those volatile components of foods that have flavour significance. The method leads to quantitative flavour specifications called charm that can be displayed graphically. The procedure is based upon the relative odour detection thresholds of volatile compounds of known gas chromatographic retention indices.     

Evaluation of dosimeter tubes for monitoring phosphine fumigations

Within integrated pest management options, fumigation of stored products is one method to help control post-harvest insect infestations in our food and agricultural products. Fumigant gas concentration monitoring is important to confirm that the treatment was adequate to achieve the desired insect control, but monitoring can be relatively expensive and labor intensive. This study evaluated how accurately dosimeter tubes could monitor phosphine fumigation treatments. The dosimeter tube is designed to continuously react with phosphine gas during the fumigation period and yields a measurement in terms of concentration 1 time product or CT, which can be interpreted as cumulative exposure. Two models of dosimeter tubes were evaluated (high range and low range). The reference method for these trials were wireless phosphine monitoring sensors, which recorded gas concentrations at hourly intervals during an exposure, and from this a CT product was also calculated. Model LPG-1, high-range dosimeter tube, measured within ± 25% of the phosphine monitoring sensors for CT dosages less the 70,000 ppm1hr. Model LPG-2, low-range tube, tended to significantly over-estimate phosphine CT dosage by 50%–100% of the phosphine monitoring sensor references. Secondly, bioassays of fumigant efficacy were performed using susceptible and resistant adult Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), lesser grain borers, and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), red flour beetle, for estimating insect control at the varied fumigation CT treatments. For the susceptible strains, CT dosages ∼5000 ppm1hr controlled both species. However, the insect control varied from 60% to 100% for resistant adults at CT dosages of ∼20,000 ppm1hr. The dosimeter tubes function in these ranges of dosages where each insect species are controlled and the dosimeter tube model LPG-1 provides reasonable estimates of the fumigation dosage for a given treatment level.     

Estimation and analysis of cow-level cumulative lifetime break-even on financial resiliency

A dairy farm's ability to generate positive profit is dependent on the cow's response to management decisions made in conjunction with input cost management. Therefore, farm managers consider a multifaceted set of choices, managing their herd not as a homogeneous group of animals, but justifying the influence of individual cows on the farm's financial performance. We combined cow-level performance records from Minnesota DHIA and farm-level financials from the University of Minnesota Center for Farm Financial Management database FINBIN (https://finbin.umn.edu/) from 2012 to 2018 to evaluate farm- and cow-level profitability. The objective of this study was to evaluate individual cow performance matched with farm-level input expenses allocated to the cow level to measure a dairy farm's ability to be profitable over time, considering input and milk price fluctuations. Conventional Minnesota dairy farms were divided into 2 groups—financially resilient and non-resilient—based on their adjusted net farm income ratio over time. Yearly farm-level expenses and revenues were allocated to cows based on performance measures provided in monthly DHIA test data, and a cumulative lifetime break-even was calculated for all cows with consecutive farm data from 2012 to 2018. Herd-level and cow-level characteristics were analyzed to test for statistical difference between resilient and non-resilient farms as well as cows who achieved their break-even versus those that did not for resilient and non-resilient farms. Results showed that resilient farms had statistically different and lower expenses than non-resilient farms, with lower heifer raising expenses ($1,839.32 vs. $1,886.20), lifetime feed expenses ($4,197.07 vs. $4,975.39), and lifetime non-feed expenses ($2,761.63 vs. $4,502.67). Resilient farms had 38.3% of cows reach break-even, whereas non-resilient farms had 25.2% of cows break even. On average, cows who achieved their break-even remained in the herd for approximately 1 yr longer for both resilient farms (1,011 d for cows who break even and 627 d for those that do not) and non-resilient farms (1,033 d for cows who break even and 683 d for those that do not). Cows on resilient farms who achieved their lifetime break-even had an average lifetime profit of $1,613.48, which was $3,095.10 higher than the lifetime profit of ?$1,481.62 of cows who never reach their break-even. Cows who reached their break-even on non-resilient farms had a lifetime profit of $1,270.51, which was $3,854.11 higher than the lifetime profit of ?$2,583.60 for those who did not break even. Therefore, financially resilient dairy farms were utilizing a low-input, low-output model that proved to be successful and resulted in maintained profitability across volatile and fluctuating commodity prices.     

Sensitivity analysis of continuous ohmic heating process for multiphase foods

The process sensitivity analysis of continuous Ohmic heating process for soup products containing large particulates was performed by use of a validated computer modeling package to determine the critical control factors and their acceptable control ranges under given control targets. The major processing variables investigated included electrical conductivities of carrier fluid and particles, particle thermal diffusivity, surface heat transfer coefficient, particle size, particle concentration, flow rate, and initial product temperature. The response variables as the indicators of effects from processing variable deviations were the process temperatures and accumulated lethality values for both carrier fluid and particles at the end of holding tube. The results demonstrated that under giving base processing conditions with a control target process temperature of 133 °C (the carrier fluid temperature at the entrance of the holding tube or the end of heating tube), increasing carrier fluid electrical conductivity from 1.42 to 2.13 S/m at a reference temperature of 70 °C, particle size from 16 to 24 mm, and flow rate from 1600 to 2400 L/h could result in lower particle center temperature at the end of holding tube, while increasing particle electrical conductivity from 0.96 to 1.44 S/m at a reference temperature of 70 °C, thermal diffusivity from 1.16 × 10⁻⁷ to 1.74 × 10⁻⁷ m²/s, surface heat transfer coefficient from 112 to 168 W/°C/m², particle concentration from 52% to78%, and initial product temperature from 56 to 84 °C could generate higher particle center temperature. Within the variable deviation ranges investigated, the importance order of effects of major processing variables were determined with respect to the particle center temperatures, carrier fluid temperatures and accumulated lethality values. The acceptable deviation ranges were built up for six major processing variables under meeting the required target Fo (at the particle center) values. The information and knowledge obtained from this study can be useful for understanding how major processing variables of continuous Ohmic heating processing system affect the required process target variables and the methodology developed in this study can be further used as a protocol for both process establishment and optimization purposes.     

A procedure for the measurement of fats in foods

The conditions for a rapid and reproducible procedure for the determination of fat in foodstuffs, based on extraction with a mixture of chloroform and methanol, are described. The procedures gives results comparable with those obtained by methods based on either acid or alkaline pretreatment of the sample and also provides an extract of the lipids in the food in a form suitable for qualitative investigations.     

A simplified procedure for fractionating plant materials.

Sequential extraction of plant materials with methanol–chloroform–water and phenol–acetic acid–water mixtures gave good yields of water-soluble low-molecular-mass substances, lipids, proteins and polysaccharides in separate fractions unlaboriously and with little chemical damage. Results with potato tubers (Solanum tuberosum L.), leafy shoots of lucerne (Medicago sativa L.) and an oilseed (Pentaclethra macrophylla Benth.) are presented.     

A generic procedure to monitor Maillard-derived fluorescent compounds in cookies by flow-injection analysis

Flow-injection analysis is proposed for routine measurement of Maillard-derived fluorescent compounds (FC) in cookies as a marker of the extent of baking. In addition, procedure was applied to investigate the formation of free and total (bound to protein free) FC in cookie-resembling models and in commercial wheat-based cookies as well. FC accounts for the overall fluorescence response of Maillard-derived fluorescent compounds (bound or not to protein) formed during baking but not for a single compound. Free and total FC values increased exponentially during baking at 200, 210 and 220 °C and an induction period of 10 min was observed for free FC. In the complex scenario of the progress of the Maillard reaction (MR) during baking, formation of FC (347/415, ext/emm) was not the limiting step for browning development at the advanced stage of the reaction. Furthermore, the formation of Maillard-derived fluorescent compounds and browning during baking were a consequence of parallel reactions apart from the classical MR scheme of consecutive reactions. Total/free FC ratio was dependent on the baking conditions applied and ratio was significantly decreased at severe baking conditions. Total/free FC ratio could be used as a reference marker for monitoring the process and to identify potential over-processing situations during baking. In addition, fluorescent residues were originally bound to protein because total/free FC ratio decreased drastically as increased the temperature and time of the process. Levels of total FC were nearly 20-fold of free FC in commercial samples. Values of FC were positively correlated with acrylamide, a Maillard-derived food processing contaminant.     

Reproduction of phosphine resistant Rhyzopertha dominica (F.) following sublethal exposure to phosphine

Phosphine fumigation is commonly used to disinfest grain of insect pests. In fumigations which allow insect survival the question of whether sublethal exposure to phosphine affects reproduction is important for predicting population recovery and the spread of resistance. Two laboratory experiments addressed this question using strongly phosphine resistant lesser grain borer, Rhyzopertha dominica (F.). Offspring production was examined in individual females which had been allowed to mate before being fumigated for 48 h at 0.25 mg L^?1. Surviving females produced offspring but at a reduced rate during a two-week period post fumigation compared to unfumigated controls. Cumulative fecundity of fumigated females from 4 weeks of oviposition post fumigation was 25% lower than the cumulative fecundity of unfumigated females. Mating potential post fumigation was examined when virgin adults (either or both sexes) were fumigated individually (48 h at 0.25 mg L^?1) and the survivors were allowed to mate and reproduce in wheat. All mating combinations produced offspring but production in the first week post fumigation was significantly suppressed compared to the unfumigated controls. Offspring suppression was greatest when both sexes were exposed to phosphine followed by the pairing of fumigated females with unfumigated males and the least suppression was observed when males only were fumigated. Cumulative fecundity from 4 weeks oviposition post fumigation of fumigated females paired with fumigated males was 17% lower than the fecundity of unfumigated adult pairings. Both of these experiments confirmed that sublethal exposure to phosphine can reduce fecundity in R. dominica.     

A simple and efficient procedure for transformation of Schizosaccharomyces pombe

We describe a simple and efficient procedure for transformation of Schizosaccharomyces pombe. Sz. pombe colonies grown on minimal (SD) plates were directly removed and suspended in a 100 microl reaction mixture containing 70 microl PLATE solution (50% polyethylene glycol-4000, 100 mM lithium acetate, 10 mM Tris-HCl, pH 4.9, and 1 mM EDTA), 10 microl plasmid DNA (1 microg), 10 microl carrier DNA (100 microg) and 10 microl sterile distilled water. After incubation at 30 degrees C for 1 h followed by heat shock treatment at 42 degrees C for 15 min, the reaction mixture was spread on a selection plate. The transformation efficiency obtained using the procedure was approximately 8000 transformants/microg DNA. The method is simple and time-saving, making it especially useful for a large number of samples and when a high transformation efficiency is not required.     

一种新型移动式流体装卸设备

针对传统的固定座流体装卸臂在混装码头使用的局限性,提出了使用移动式流体装卸设备的设想。对这种新型设备从使用目的、设计思路及机动性、安全性、可靠性等方面进行了论述。对设备的各部分的作用和结构特点进行了介绍,并重点论述了该设备在设计和配置上的独到之处和创新点。最后介绍了该设备在粮油码头的实际应用情况。     

Effect of technological processes and storage on flavonoids content and total, cumulative fast-kinetics and cumulative slow-kinetics antiradical activities of citrus juices

Juices from the mandarin Clemenules (Citrus clementina Hort. ex Tan.), the tangor Ortanique (Citrus reticulata Blanco × Citrus sinensis Osb.) and the sweet orange Valencia Late (Citrus sinensis) have been industrially squeezed, pasteurized, concentrated and stored under refrigeration (4 °C) and at room temperature (20 °C). After each process, the flavanone-7-O-glycosides (FGs) and fully methoxylated flavones (FMFs) contents as well as total, cumulative fast-kinetics and cumulative slow-kinetics antiradical activities were determined and compared with those from the corresponding fresh hand-squeezed juices. Neither industrial-squeezing, nor pasteurization or concentration significantly affected FGs and FMFs contents and antiradical activities of assayed juices. Storage caused a slight decrease of the FMFs contents but a significant reduction of both soluble hesperidin contents and cumulative fast-kinetics antiradical activities in all assayed juices. These decreases were dependent on storage temperature. Characteristic values of the varietal characterization parameters, which are derived from the FMFs contents and antiradical activities of fresh hand-squeezed juices, held valid for industrially squeezed, pasteurized and concentrated juices. After storage, however, only the FMFs-derived varietal characterization parameters and cumulative slow-kinetics antiradical activity remained valid for the resulting juices.     

Resistance to phosphine in Sitophilus oryzae in Australia: A national analysis of trends and frequencies over time and geographical spread

In Australia, along with many other parts of the world, fumigation with phosphine is a vital component in controlling stored grain insect pests. However, resistance is a factor that may limit the continued efficacy of this fumigant. While strong resistance to phosphine has been identified and characterised, very little information is available on the causes of its development and spread. Data obtained from a unique national resistance monitoring and management program were analysed, using Bayesian hurdle modelling, to determine which factors may be responsible. Fumigation in unsealed storages, combined with a high frequency of weak resistance, were found to be the main criteria that led to the development of strong resistance in Sitophilus oryzae. Independent development, rather than gene flow via migration, appears to be primarily responsible for the geographic incidence of strong resistance to phosphine in S. oryzae. This information can now be utilised to direct resources and education into those areas at high risk and to refine phosphine resistance management strategies.     

磷化氢环流熏蒸生产性应用研究

以高大房式仓散存硬麦为实验对象,运用磷化氢环流熏蒸装备,分别采用仓外施药、仓外与粮面施药相结合、仓外与粮面间歇投药法不同方式生产性应用。根据不同区域和厂房条件,可以制定经济、安全、有效的熏蒸工艺,节省熏蒸时间,且浓度均匀,杀虫效果好。     

Development and analysis of a rumen tissue sampling procedure

A procedure for rumen tissue sampling was developed to determine treatment effects on rumen development and papillae growth in young calves and to improve repeatability in rumen tissue sampling techniques. Rumens were collected from 42 male Holstein calves from 4 separate experiments. Rumen sampling areas (n = 9) included the caudal dorsal blind sac, cranial dorsal sac, cranial ventral sac, and the caudal and ventral portions of the caudal ventral blind sac. Right and left sides of the rumen were sampled. Five 1-cm2 sections were removed from each area and measured for papillae length (n = 20/area), papillae width (n = 20/area), rumen wall thickness (n = 5/area), and number of papillae per cm2 (n = 5/area). Correlations between areas, samples, and measurements were obtained, and comparisons between experiments, areas, samples, and measurements were performed for all variables. In addition, power analyses were conducted for all variables to determine the efficacy of the procedure in detecting treatment differences. Results indicate that samples should be taken from the caudal and cranial sacs of the dorsal and ventral rumen to sufficiently represent papillae growth and development throughout the entire rumen. The procedure is capable of detecting treatment differences for papillae length and papillae width, has a decreased but acceptable capability of detecting treatment differences for rumen wall thickness, but appears limited in ability to detect treatment differences for papillae per square centimeter. In conclusion, rumen tissue sampling to determine extent of rumen development in calves can be performed in a nonbiased and repeatable manner utilizing a limited number of calves.     

A proposed standard procedure for taint tests with agricultural chemicals

Summary. This paper has been prepared under the auspices of the Advisory Committee on Taint of the Ministry of Agriculture, Fisheries and Food and is intended to meet the need for a standard procedure for taint tests with agricultural chemicals on processed foodstuffs of plant origin. the paper is divided into two main parts. the first section deals with trial design and site, chemical application, crops, sampling procedure, packing of raw materials, transport and storage of samples, processing and number of tests required to indicate whether a chemical substance may be accepted as being free from tainting characteristics. the second section deals with various aspects of the tasting tests, such as method employed, suitability and numbers of tasters, place and time of tasting and preparation of samples for tasting. the proposed method of tasting is the triangular test and details of calculating the results are given, together with appendices presenting the necessary tables and a worked example.