AQUEOUS GARLIC EXTRACT AND MICROBIOLOGICAL QUALITY OF REFRIGERATED POULTRY MEAT

The antibacterial effect of garlic extract (5, 10 and 15%) was investigated on poultry carcasses obtained from a slaughterhouse, stored under refrigeration, and evaluated at selected time intervals. The effect of the garlic extract on the microbial contaminants of the poultry carcass surface – Salmonella, strict and facultative aerobic, mesophilic, and total and fecal coliforms – was evaluated. The garlic extract exhibited a concentration‐dependent reduction of microbial contamination. Garlic extract concentrations of 10 and 15% were the most effective. The bacteriostatic action of garlic extract against mesophilic microbiota can be observed until the third storage day. The count of total and fecal coliforms remained low during the storage period. Chicken feed was the apparent source of Salmonella contamination, and the aqueous garlic extract was not effective against Salmonella.     

Textural and Microstructural Changes in Frozen Stored Sardine Mince Gels

The freezing of sardine mince gels produced slight alterations in texture, microstructure and degree of chemical aggregation of proteins, irrespective of freezing temperature (– 18°C or – 40°C). The most noticeable changes took place during frozen storage 3 mo, particularly in gels frozen at – 18°C which were strongly affected by storage temperature (– 12°C or – 18°C), unlike those frozen at – 40°C. Better gel integrity was found in those frozen at – 40°C, where cavities were more numerous, but smaller and more evenly distributed than in gels frozen at – 18°C.     

Factors influencing the determination of nisin in meat products

Recovery of nisin from minced meat and meat emulsions was poor and variable. The rate of recovery was little affected by the presence of NaCl and/or NaNO₂, particle size, or the meat to extractant (0.02N HCl) ratio, but was significantly affected by the fat content of the meat. For nisin added at 100 iu/g, recoveries at the optimal meat to extractant ratio, 10% wt/wt suspension, ranged from 26% at 3% fat to 76% at 83% fat. At addition levels of 200 iu/g and greater, nisin recovery efficiency was reduced.     

The Asian cyclopoid copepod Mesocyclops pehpeiensis Hu 1943 reported from the western basin of Lake Erie

The Asian cyclopoid copepod Mesocyclops pehpeiensis Hu, 1943 has been reported as an introduced species at several locations in the western hemisphere. In the United States, reports of this exotic species are restricted to localities in Louisiana, Mississippi, and Washington D.C. This report documents a new record of occurrence for M. pehpeiensis from the western basin of Lake Erie. The detection of M. pehpeiensis in Lake Erie constitutes the first record of this species from the Laurentian Great Lakes, and the northernmost record in the western hemisphere. The species was found in 2016, 2017 and 2018, including females with egg sacs, and can therefore be considered established in the area. The occurrence of M. pehpeiensis in Lake Erie suggests that this Asian copepod may be more widely distributed in North America than is currently understood.     

Status of Mysis diluviana in Lake Ontario in 2013: Lower abundance but higher fecundity than in the 1990s

Mysis diluviana is a major component of prey fish diets in the Great Lakes, so annual production of M. diluviana is important for understanding and modeling energy flow through Great Lakes food webs. However, only three lake-wide measurements of M. diluviana annual production in Lake Ontario are currently available (1971, 1990, 1995). During 2013, lake-wide coverage of Lake Ontario was achieved during four periods from April to November. Annual mean density and biomass of M. diluviana in 2013 were 99?#/m² (SE: 8) and 318?mg?dw/m² (SE: 28) – approximately half of values observed in 1990s. M. diluviana comprised 13–30% of offshore zooplankton biomass in each period. Reproduction peaked in fall, with mean brood size of 32 embryos (range: 11–49), at least 10% larger than in 1990s. Generation time was two years from embryo to initial reproduction. Growth rates were 0.052?mm/d for the age-0 cohort and 0.027?mm/d for the age-1 cohort. Age-0 growth rate was significantly higher than in 1980s–90s (0.035?mm/d). Annual production in 2013 was 0.85?g?dw/m²/yr (SE: 0.03) which was 30–40% of values observed in 1990 and 1995 (2.23 and 2.53?g/m²/yr). Annual production to biomass ratio (P/B) in 2013 was 2.65?/yr which was 80–85% of values observed in 1990 and 1995 (3.24 and 3.11?/yr), but this difference was not statistically significant. Our results suggest that changes in annual production over time can be estimated using changes in biomass over time and a mean P/B ratio.     

A new method to correlate acoustic spectroscopic microscopy (30 MHz) and light microscopy

A powerful new method is used to investigate the correlation between light microscopic and acoustic properties of biological tissues. Specimens of liver were sectioned into successive slices, 250 μm and 10 μm thick. The thick sections were investigated acoustically, the thin sections by means of light microscopy. Markers that could be detected and located, both optically and acoustically, were used to find and reconstruct corresponding regions in the acoustic and optical sections (2·5 × 2·5 mm). Parameter images were reconstructed from the sections investigated acoustically. The acoustic parameters were attenuation at 30 MHz, the slope of the attenuation spectrum (between 10 and 50 MHz), backscattering at 30 MHz, the slope of the backscattering spectrum (between 10 and 50 MHz) and the local ultrasound velocity. Acoustic images were obtained in the frequency range from 10 to 50 MHz, yielding a lateral resolution of about 50 μm. The sections for light microscopy were stained according to the Goldner trichrome staining technique. The histological composition was determined quantitatively, using digital image segmentation techniques. The percentage of collagen-rich fibrous tissue, luminal structure and interstitial spaces, and the number of nuclei were calculated for regions of 250 × 250 μm. These histological features were correlated with the acoustic parameters obtained from the corresponding regions in adjacent sections. It was thus possible to find the histological components responsible for acoustic parameters.     

采场配电系统继电保护存在的问题与对策

采掘场供配电的继电保护是影响安全可靠供电的重要环节,由于采掘场生产工艺的特点和运行环境条件,给继电保护管理带来一定的困难,根据具体情况合理改造和调整,可以寻求适应现场条件的保护方案,以满足生产需要和规程要求。     

Freezing Time Predictions for Brick and Cylindrical-Shaped Foods

A simplified model previously developed for freezing time calculations in plate freezers is extended to systems with two or three dimensional heat flow. The model combines Plank's equation with the unsteady heat transfer solutions for bodies with constant properties, through the addition of pre-cooling, change of phase and tempering times. Average thermal properties, different for each period are used in order to take into account their change with the ice content along the freezing process. Freezing time predictions show a maximum difference of 10% with respect to freezing experiments performed with meat blocks shaped as cylinders or rectangular bricks. Processing times from 0.7–5 hr were compared with satisfactory agreement.     

Preparation of Low Free Gossypol and High Available Lysine Cottonseed/Soybean Blends

Cottonseed/soybean blends (50/50) were ground in an Alpine pin mill with or without previous cooking in a Brady low-cost extruder. Free gossypol decreased with increasing amount of water added prior to extrusion and number of passes through the extruder. Available lysine increased with decreasing amount of added water but was unaffected by number of passes through the extruder. Type of soybean raw material utilized had no effect on free gossypol. Blends prepared from defatted cottonseed meal, however, had lower free gossypol than those made from cottonseed kernels. A blend similar to full-fat soy flour but of lower cost was prepared from unextruded 50% defatted cotton-seed meal/50% extruded soybean flakes, without added water, and ground in the Alpine mill.     

PROTEIN-PHYTATE INTERACTIONS IN SOYBEANS. II. MECHANISM OF PROTEIN-PHYTATE BINDING AS AFFECTED BY CALCIUM

Phytate and bovine serum albumin were used in a model system to investigate the mechanism of their binding. Ultrafiltration studies using response surface design showed the association of protein and phytic acid to be highly pH dependent. Under acid conditions, the protein formed an insoluble complex with phytic acid. At pH 3.0, a binding constant of 2.3 times 10⁵ was obtained and it was calculated that there are 78 binding sites of the total 93 basic amino acid residues potentially available. This low pH complex was not disrupted at high temperatures but the presence of calcium ions caused dissolution of the precipitate. Calcium produced different effects at higher pH (> 6). Soluble protein-calcium-phytic acid complexes were formed which were less stable to heat and dissociated above pH 10 at high ionic strength. Since this interaction occurred only in the presence of calcium, a salt linkage is implicated in which divalent cations simultaneously bind to the protein and phytic acid in the form of a soluble complex. It is proposed that either the addition of divalent cations at low pH or sequestering agents at high pH would best effect the removal of phytate from soy products by ultrafiltration.