Influence of breed,milk production,season, and ambient temperature on dairy cow reticulorumen temperature

Automatic monitoring of core body temperature in dairy cattle could be useful for identification of illness, heat stress, general physiological stress, and estrus. The SmartBolus (TenXSys Inc., Eagle, ID) system used a reticulorumen bolus to automatically record and transmit dairy cow temperatures. The objective of this research was to characterize the influence of milk yield (MY), time of day, breed, ambient temperature (AT), and season on reticulorumen temperatures (RT) in lactating dairy cows. Continuous RT and AT were collected by SmartBolus transponders every 15 min (96 records per d) from 93 cows (65 Holstein, 18 crossbred, and 10 Jersey) for 615 d. Mean (±SD) daily RT, AT, and MY were 40.14 ± 0.32°C, 12.20 ± 10.61°C, and 33.85 ± 8.67 kg, respectively. The maximum and minimum RT were recorded at 2330 and 1000 h, respectively. Ambient temperature increased RT. Summer RT was significantly greater than spring, fall, or winter RT. The effect of MY on RT varied by breed, season, and AT. Crossbred RT was significantly lower than Holstein RT after adjusting for MY. Crossbred RT responded less to increasing AT than did Holstein RT, potentially indicating improved heat tolerance among these crossbred dairy cows. Reticulorumen temperature increased more dramatically for cows with greater milk yield as AT increased, demonstrating that high-producing cows are more susceptible to heat stress than low-producing cows. These results could be useful in interpretation of automatic temperature system data, heat stress management, and genetic selection of heat-tolerant cows.     

The effect of temperature on dough viscosity,and its consequence for the control of dough temperature

In bakeries, it is important that successive batches of dough (‘doughs’) for the same product have the same temperature. Dough temperature can be controlled by adjusting the temperature of the water to be used. An automatic calculator for the required water temperature was designed on the basis of the assumption that the final dough temperature is a linear function of flour, water and bakery temperatures.This paper describes a physical model which predicts the values of the coefficients and of the constant term in this linear relationship. The decrease in dough viscosity with increasing temperature is an essential part of the model.It is argued that this effect of temperature on dough viscosity reduces the effects of flour and water temperatures on the final dough temperature. Heat transfer between the dough and the air in the bakery also reduces their effects, but is, under normal mixing conditions, less important than the effect of temperature on dough viscosity; only with small doughs and with slow and long mixing is it more important.     

Influence of time, temperature, moisture, ingredients, and processing conditions on starch gelatinization

Starch gelatinization phenomena is extremely important in many food systems. This review focuses on factors affecting gelatinization characteristics of starch. Important variables which must be considered in design of processes in which starch undergoes gelatinization are heat of gelatinization and temperature of gelatinization. Major interactions are reviewed for the effects of lipids, moisture content, nonionic constituents and electrolytes on these characteristics. Furthermore, treatment of starch-containing systems prior to heating into the gelatinization temperature range can have a significant effect on ultimate gelatinization characteristics.     

Association between ambient temperature and humidity,vaginal temperature,and automatic activity monitoring on induced estrus in lactating cows

The objective of this study was to determine the association between ambient temperature and humidity, vaginal temperature, and automated activity monitoring in synchronized cows. Lactating Holstein cows (n = 641; 41.5 ± 9.4 kg of milk/d) were fitted with leg-mounted pedometers, resulting in 843 evaluated activity episodes of estrus. Vaginal temperature was monitored using thermometers attached to an intravaginal device as part of a timed artificial insemination (TAI) protocol; vaginal temperature was recorded every 10 min for 3 d. Ambient temperature and relative humidity were monitored using an external thermometer placed in the center of each pen. Milk production and body condition score (BCS) data were collected at the time of thermometer insertion. All statistical analysis was performed in R (https://www.r-project.org/) using Pearson correlation, analysis of variance, and logistic regression. Heat stress was calculated based on the percentage of time the cow spent with a vaginal temperature ≥39.1°C (PCT39) 9 to 11 d before TAI, and was classified as high (≥22.9%) or low (<22.9%). The mean vaginal temperature was 38.9 ± 0.2°C, and the mean maximum and minimum vaginal temperatures were 39.7 ± 0.5°C and 38.0 ± 0.8°C, respectively, with an average amplitude of 1.71 ± 0.9°C. Mean relative increase (RI) of estrus walking activity was 237.0 ± 160%. Animals with low BCS had a lower RI compared with cows with medium BCS (260.31 ± 17.45% vs. 296.42 ± 6.62%). Cows in early lactation showed lower RI compared with mid- and late-lactation animals (265.40 ± 9.90% vs. 288.36 ± 11.58% vs. 295.75 ± 11.29% for early, mid, and late lactation, respectively). Temperature-humidity index (THI) conditions categorized as low (THI ≤65) were associated with greater RI compared with medium (>65 to <70) and high THI (≥70). We detected no significant effect of PCT39 or milk production on RI, whereas parity exhibited a tendency. Cows that displayed greater RI at estrus had greater pregnancies per artificial insemination (P/AI) than cows with low RI (27 vs. 20%) or no RI (27 vs. 12%). Primiparous cows had greater P/AI than multiparous cows (27 vs. 20%), and cows in early and mid lactation had improved P/AI than those in late lactation (26 vs. 22 vs. 16% for early, mid, and late lactation, respectively). An interaction was observed between PCT39 and THI on P/AI, where a subpopulation of cows with high PCT39 had decreased P/AI under high THI conditions, but no differences in P/AI were observed for high PCT39 cows under medium or low THI conditions (13 vs. 24 vs. 26%). Future research should aim to refine variables related to hyperthermia and to understand the effects of body temperature on estrus expression and pregnancy rates.     

酸的种类、pH和温度对酸性纤维素酶活力的影响

以8种酸(甲酸、冰醋酸、羟基乙酸、乳酸、柠檬酸、酒石酸、氨基乙酸和氨基磺酸)配制成pH=5.0的缓冲液,测定酸性纤维素酶在各缓冲液中的活力.同时以冰醋酸作为pH调节剂,采用中心合成设计法,分析和优化pH和温度对酶活力的影响,得出线性回归方程和优化值.结果表明,在pH=5.0的条件下,乳酸和酒石酸为酸剂的酶活力高于冰醋酸,羟基乙酸、甲酸和柠檬酸比冰醋酸略低,而氨基乙酸和氨基磺酸明显低于冰醋酸;采用冰醋酸调节pH,酶活力随着温度的升高和pH的降低而增加,pH影响的显著性要大于温度.酸性纤维素酶在49.8℃,pH=4.8可以实现最佳的活力.     

生猪宰前皮温、宰后肉温及pH值对肉品质量影响

生猪屠宰后,肉尸(胴体)会产生系列新陈代谢变化.这一过程和结果直接关系到肉品卫生安全质量.宰前皮肤温度与宰后肌肉温度及pH值变化,是影响猪肉品质的三个主要因素.宰前充分休息与饮水,宰后严格冷却工艺和屠宰修正工艺是提高肉品品质的重要措施.     

Combined effects of temperature, water activity, and pH on Alicyclobacillus acidoterrestris spores

A response surface model was developed to describe the effects of temperature (35 to 55 degrees C), pH (3.5 to 5.5), and water activity (a(w), 0.960 to 0.992) on germination of Alicyclobacillus acidoterrestris spores. Germination and growth or viability loss depended, to varying extents, on the interactions among the independent variables and the complexity of the medium. In particular, maximum growth was achieved at temperatures between 35 and 42 degrees C and at pH values from 3.5 to 4.5. The model was validated against data not used in its development. Bias factors of 0.999 and 0.817 for 2- and 7-day models, respectively, were obtained, indicating that the models were "fail safe." Results indicated that the model provided reliable predictions of growth of A. acidoterrestris spores.     

Effects of pressure,shear, temperature,and their interactions on selected milk quality attributes

The effects of pressure, temperature, shear, and their interactions on selected quality attributes and stability of milk during ultra-shear technology (UST) were investigated. The UST experiments include pressure (400 MPa) treatment of the milk sample preconditioned at 2 different initial temperatures (25°C and 15°C) and subsequently depressurizing it via a shear valve at 2 flow rates (low: 0.15–0.36 g/s; high: 1.11–1.22 g/s). Raw milk, high-pressure processed (HPP; 400 MPa, ~40°C for 0 and 3 min) and thermal treated (72°C for 15 s) milk samples served as the controls. The effect of different process parameters on milk quality attributes were evaluated using particle size, zeta potential, viscosity, pH, creaming, lipase activity, and protein profile. The HPP treatment did not cause apparent particle size reduction but increased the sample viscosity up to 3.08 mPa·s compared with 2.68 mPa·s for raw milk. Moreover, it produced varied effects on creaming and lipase activity depending on hold time. Thermal treatment induced slight reduction in particle size and creaming as compared with raw milk. The UST treatment at 35°C reduced the effective diameter of sample particles from 3,511.76 nm (raw milk) to 291.45 nm. This treatment also showed minimum relative lipase activity (29.93%) and kept milk stable by preventing creaming. The differential effects of pressure, shear, temperature, and their interactions were evident, which would be useful information for equipment developers and food processors interested in developing improved food processes for dairy beverages.     

Mastitis: effect of pH, temperature, and emollients on disinfecting action of N,N-dimethyldodecanamine

Growth inhibition of bacteria over time by N,N-dimethyldodecanamine, a tertiary alkyl amine, was studied to evaluate disinfecting action with changes in pH and temperature and with addition of emollients. Because alkyl amines have limited solubility in aqueous solutions, the effect of pH on solubility of the tertiary amine was determined. Non-growing cultures of Streptococcus agalactiae or Escherichia coli were added to sterile buffer or buffer containing the amine, and at specific intervals aliquots were removed, neutralized in a lecithin/Tween 80 quencher, and then plated to determine the number of surviving bacteria per plate. Survival curves were used to determine the effect of changing environmental conditions on antimicrobial activity. Antimicrobial activity was greater at pH 7 than at pH 8 and was least at pH 6. Increases in temperature from 20 to 40 degrees C caused a corresponding increase in antimicrobial activity. Addition of up to 10% glycerin or propylene glycol caused no significant decrease in antimicrobial activity of the tertiary amine.     

Effect of pH,concentration, and temperature on the strength of cytoplasmic protein foams

The strength of foams generated from solutions of red clover cytoplasmic protein is dependent on pH, protein concentration, arid temperature. The variation of foam strength as a function of these three parameters has been studied and results indicate that the onset of foam stability occurs over very short concentration and temperature ranges. A phase diagram for these foams is proposed which defines the differences between stable and unstable states in terms of protein concentration and temperature. The results show that above 40°c only unstable foams are generated, irrespective of protein concentration. Below 40°c, stable foams can be generated provided the protein concentration is greater than a certain critical concentration for the system. A possible implication in bloat studies is suggested.     

Nisin、ε-聚赖氨酸和温度对枯草芽孢杆菌失活动力学的影响

以源自熟制对虾虾仁的优势腐败菌枯草芽孢杆菌为对象,对温度(25、37和45℃)、Nisin和ε-聚赖氨酸在酸性环境(p H=5)作用下其失活效应进行分析,并采用线性模型、Weibull模型、Log-logistic模型对不同处理条件下枯草芽孢杆菌的失活动力学进行拟合和评价。结果表明:25～45℃时,枯草芽孢杆菌失活量随Nisin和ε-聚赖氨酸的浓度变化而变化。温度由25℃升高至45℃,Nisin和ε-聚赖氨酸作用下枯草芽孢杆菌失活量呈先升后降趋势,37℃时失活效果最佳,25℃和45℃时,ε-聚赖氨酸作用下的失活效果优于Nisin,37℃时,两者差异不显著。处理180 min终点枯草芽孢杆菌数均降至0。Log-logistic模型与Weibull模型均能很好拟合其失活过程,而线性模型难以描述失活动力学,Log-logistic模型拟合优度优于Weibull模型。通过构建虾源枯草芽孢杆菌在温度、Nisin和ε-聚赖氨酸作用下失活模型,为优化靶向生物杀菌和延长水产品货架期等提供依据。     

Rheological properties of polysaccharides from Pholiota nameko with different temperature extraction: Concentration,pH, temperature,and saltion

Cold and hot water extracted polysaccharides (CW-PNPs and HW-PNPs) were isolated from Pholiota nameko. The rheological properties of PNPs were investigated by steady shear and oscillatory rheological measurements. The PNPs exhibited typical non-Newtonian and shear-thinning behavior, which are affected by PNP concentration, temperature, pH value, salt ion, and concentration. Specifically, the apparent viscosity of the two PNPs solutions at concentration of 1% (w/w) was shown as HW-PNPs > CW-PNPs. The apparent viscosity of PNPs decreases under acidic and alkaline conditions and when the temperature rises; K⁺ and Na⁺ cause the apparent viscosity of CW-PNPs to decrease, while Ca²⁺ and Al³⁺ are opposite. The addition of four different salt ions all caused the apparent viscosity of the HW-PNPs to decrease. The results of dynamic rheological experiments show that G′ and G″ showed slightly frequency dependency with G′ exceeding G″ throughout the accessible range of frequency for CW-PNPs and HW-PNPs.     

Effect of high pressure, temperature, and storage on the color of porcine longissimus dorsi

The color of pork longissimus dorsi high pressure (HP) treated at 200 to 800MPa at 5 and 20°C for 10min was determined to a high degree by pressure level and to a lesser degree by temperature. Severe color changes appeared up to a threshold pressure at 400MPa. HP treatment at 20°C compared to 5°C resulted in meat, which was less red and slightly lighter. Storage at 2°C for 6days had no effect on lightness due to no further protein denaturation, but meat HP treated above 300MPa became significantly less red and more yellow within the first day of storage. Reflectance spectra showed that a short-lived ferrohemochrome myoglobin species was formed during HP treatment at 300 to 800, but transformed into a brown, ferric form of the pigment within the first day of storage. This explains the observed changes in the redness and yellowness after one day of storage.     

Influence of brine concentration and temperature on composition, microstructure, and yield of feta cheese

The protein matrix of cheese undergoes changes immediately following cheesemaking in response to salting and cooling. Normally, such changes are limited by the amount of water entrapped in the cheese at the time of block formation but for brined cheeses such as feta cheese brine acts as a reservoir of additional water. Our objective was to determine the extent to which the protein matrix of cheese expands or contracts as a function of salt concentration and temperature, and whether such changes are reversible. Blocks of feta cheese made with overnight fermentation at 20 and 31°C yielded cheese of pH 4.92 and pH 4.83 with 50.8 and 48.9 g/100 g of moisture, respectively. These cheeses were then cut into 100-g pieces and placed in plastic bags containing 100 g of whey brine solutions of 6.5, 8.0, and 9.5% salt, and stored at 3, 6, 10, and 22°C for 10 d. After brining, cheese and whey were reweighed, whey volume measured, and cheese salt, moisture, and pH determined. A second set of cheeses were similarly placed in brine (n = 9) and stored for 10 d at 3°C, followed by 10 d at 22°C, followed by 10 d at 3°C, or the complementary treatments starting at 22°C. Cheese weight and whey volume (n = 3) were measured at 10, 20, and 30 d of brining. Cheese structure was examined using laser scanning confocal microscopy. Brining temperature had the greatest influence on cheese composition (except for salt content), cheese weight, and cheese volume. Salt-in-moisture content of the cheeses approached expected levels based on brine concentration and ratio of brine to cheese (i.e., 4.6, 5.7 and 6.7%). Brining at 3°C increased cheese moisture, especially for cheese with an initial pH of 4.92, producing cheese with moisture up to 58 g/100 g. Cheese weight increased after brining at 3, 6, or 10°C. Cold storage also prevented further fermentation and the pH remained constant, whereas at 22°C the pH dropped as low as pH 4.1. At 3°C, the cheese matrix expanded (20 to 30%), whereas at 22°C there was a contraction and a 13 to 18 g/100 g loss in weight. Expansion of the protein matrix at 3°C was reversed by changing to 22°C. However, contraction of the protein matrix was not reversed by changing to 3°C, and the cheese volume remained less than what it was initially.     

Effect of high pressure,temperature, and storage on the color of porcine longissimus dorsi

The color of pork longissimus dorsi high pressure (HP) treated at 200 to 800 MPa at 5 and 20 °C for 10 min was determined to a high degree by pressure level and to a lesser degree by temperature. Severe color changes appeared up to a threshold pressure at 400 MPa. HP treatment at 20 °C compared to 5 °C resulted in meat, which was less red and slightly lighter. Storage at 2 °C for 6 days had no effect on lightness due to no further protein denaturation, but meat HP treated above 300 MPa became significantly less red and more yellow within the first day of storage. Reflectance spectra showed that a short-lived ferrohemochrome myoglobin species was formed during HP treatment at 300 to 800, but transformed into a brown, ferric form of the pigment within the first day of storage. This explains the observed changes in the redness and yellowness after one day of storage.     

Effect of pH, NaCl content, and temperature on growth and survival of Arcobacter spp

Growth and survival of six human isolates of the pathogenic Arcobacter spp. in the presence of selected environmental factors were studied. Four strains of Arcobacter butzleri and two strains of Arcobacter cryaerophilus were exposed to pH levels of 3.5 to 8.0. Most strains grew between pH 5.5 and 8.0, with optimal growth of most A. butzleri and A. cryaerophilus strains at pH 6.0 to 7.0 and 7.0 to 7.5, respectively. The 24-h optimal growth range in the presence of NaCl was 0.5 to 1.0% for A. cryaerophilus. However, after 96 h, the optimum was between 0.5 and 2.0% NaCl. The optimum range for growth of A. butzleri strains was 0.09 to 0.5% NaCl after 96 h. The upper growth limits were 3.5 and 3.0% NaCl for A. butzleri and A. cryaerophilus, respectively. Survival at 25 degrees C in up to 5% NaCl was noted for A. butzleri 3556 and 3539 and A. cryaerophilus 3256. Decimal reduction times (D-values) at pH 7.3 in phosphate-buffered saline for three A. butzleri strains were 0.07 to 0.12 min at 60 degrees C, 0.38 to 0.76 min at 55 degrees C, and 5.12 to 5.81 min at 50 degrees C. At pH 5.5, decreased thermotolerance was observed, with D-values of 0.03 to 0.11 min at 60 degrees C, 0.30 to 0.42 min at 55 degrees C, and 1.97 to 4.42 min at 50 degrees C. Calculated z-values ranged from 5.20 to 6.28 degrees C. D-values of a three-strain mixture of A. butzleri in raw ground pork were 18.51 min at 50 degrees C and 2.18 min at 55 degrees C. Mild heat (50 degress C) followed by cold shock (4 or 8 degrees C exposure) had a synergistic lethal effect, reducing more cells than with an individual 50 degrees C treatment or with cold shock temperatures of 12 or 16 degrees C.     

Effect of time,temperature and humidity on biodeterioration of corn cake snack

Food spoilage microorganisms representing 5, 6 and 10 genera of moulds, yeasts and bacteria, respectively were isolated from corn cake snack. Each of the samples analysed had initial pH value favourable to microbial growth and activities while only 28% had spoilage-enhancing moisture contents (> 13%). The effect of temperature and relative humidity (RH) on biodeterioration during a 24-day storage period was determined by monitoring changes in the pH and total microbial colony counts. Whereas very little or no deterioration was recorded for samples contained in 51% and 71% RH chambers at 30 and 45 °C, substantial deterioration was obtained at the same temperatures under 89.5% and 100% RH. At 15 °C, very little or no deterioration was detected except under 79.5%, 89.5% and 100% RH when slight spoilage changes were recorded as from the 12th or 18th day. The overall results show that the obtained colony counts and pH values monitor spoilage equally.     

Effects of temperature, photoperiod, and light quantity on protein production in wheat grains.

Five varieties of common spring wheat were cultivated under controlled conditions at five temperatures from 12 to 24 °C. From the time of heading three day-length treatments were applied at each temperature: 10 h, 24 h, and natural day length. Nitrogen content in the grains increased by 46–124% with increasing temperature, and also increased significantly with extension of the photoperiod. Natural days, supplying more light energy, gave lower nitrogen contents than the other treatments. Protein yields per pot were more constant. The relative amounts of lysine, valine, and threonine decreased with increasing temperature and extension of the photoperiod, while glutamic acid, proline, and phenylalanine increased. However, at the highest temperatures this trend was hardly apparent. Protein fractionation showed that the decrease in lysine was correlated with an increase in the ratio of alkali-soluble to salt-soluble proteins.     

Characteristics on host specificity,infection, and temperature stability of Weissella phages from watery kimchi

Three bacteriophages (phage), ΦWC53, ΦWC54, and ΦWC56, of Weissella were isolated from watery kimchi and characterized. ΦWC53 belonged to Siphoviridae and ΦWC54 and ΦWC56 belonged to Myoviridae family. By one-step growth, the burst sizes were 5–260 particles/infected cells and the latent periods were 20–45 min. The phages infected Weissella spp., Leuconostoc mesenteroides, and Lactobacillus spp., differently by showing clear or turbid plaques. The phage adsorption rates on lactic acid bacteria were high on Weissella and low on Leuconostoc and Lactobacillus. However, the adsorption of ΦWC53 occurred variously among Weissella spp. and Weissella host grew well in the liquid culture without lysis after challenging by ΦWC53. Tolerances of these phages to temperature showed more various than those to pH. ΦWC53 was stable at 7 °C and 30 °C, but ΦWC54 and ΦWC56 were stable only at 7 °C. Therefore, three Weissella phages belonged to the different families and indicated diverse infection patterns on Weissella, Leuconostoc, and Lactobacillus with various stabilities for pH and temperature.