Inhibition of Listeria monocytogenes growth in cured ready-to-eat meat products by use of sodium benzoate and sodium diacetate.

The effect of sodium benzoate (0.08 to 0.25%) in combination with different concentrations of sodium diacetate (0.05 to 0.15%) and NaClI (0.8 to 2%) and different finished product moisture (55 to 75%) on the growth of Listeria monocytogenes in ready-to-eat meat products was evaluated using a central composite design over 18 weeks of storage at 4 degrees C. The effects of these factors on time to growth were analyzed using a time-to-failure regression method. All main effects were significant except product moisture, which was significant when included in the two- and three-way interactions (P < 0.05). Sodium benzoate was more effective (lengthening time to growth) when used with increasing concentrations of sodium diacetate and salt and decreasing finished product moisture. The model indicated that low-moisture products, e.g., bologna or wieners, could have time-to-growth values longer than 18 weeks if they were formulated with 0.1% sodium benzoate and 0.1% sodium diacetate. Time to growth in high-moisture products, e.g., ham or cured turkey breast at 75% moisture, was predicted to be much shorter for the same basic formulation (0.1% sodium benzoate and 0.1% sodium diacetate). Consequently, high-moisture ready-to-eat products in which sodium benzoate is limited to 0.1% (current standard for generally recognized as safe) may need additional ingredients to effectively inhibit growth of L. monocytogenes.

Modeling the growth boundary of Listeria monocytogenes in ready-to-eat cooked meat products as a function of the product salt, moisture, potassium lactate, and sodium diacetate concentrations.

A central composite response surface design was used to determine the time to growth of Listeria monocytogenes as a function of four continuous variables: added sodium chloride (0.8 to 3.6%), sodium diacetate (0 to 0.2%), potassium lactate syrup (60% [wt/wt]; 0.25 to 9.25%), and finished-product moisture (45.5 to 83.5%) in ready-to-eat cured meat products. The design was repeated for ready-to-eat uncured meat products giving a fifth categorical variable for cure status. Products were stored at 4 degrees C. The results were modeled using a generalized regression approach. All five main effects, six two-factor interactions, and two quadratic terms were statistically significant. The model was used to show the boundary between growth and no-growth conditions at 4 degrees C using contour plots of time to growth. It was validated using independent challenge studies of cured and uncured products. Generally, the model predicted well, particularly for cured products, where it will be useful for establishing conditions that prevent the growth of L. monocytogenes. For uncured products, there was good agreement overall between predicted and observed times to growth, but the model is less thoroughly validated than for cured products. The model should initially only be used for screening of formulations likely to prevent growth of Listeria monocytogenes in uncured products, with recommendations subject to confirmation by challenge studies.

Modeling the growth of Listeria monocytogenes in cured ready-to-eat processed meat products by manipulation of sodium chloride, sodium diacetate, potassium lactate, and product moisture content.

A central composite second-order response surface design was employed to determine the influences of added sodium chloride (0.8 to 3.6%), sodium diacetate (0 to 0.2%), potassium lactate syrup (0.25 to 9.25%), and finished-product moisture (45.5 to 83.5%) on the predicted growth rate of Listeria monocytogenes in cured ready-to-eat (RTE) meat products. Increased amounts of both sodium diacetate (P < 0.11) and potassium lactate (P < 0.001) resulted in significant reductions in the growth rate constants of L monocytogenes. Increased finished-product moisture (P < 0.11) significantly increased growth rate constants. The nfluence of sodium chloride was not statistically significant. The second-order statistical factor for lactate was significant (P < 0.01), but all two-way interactions were not. In general, predicted growth rates exceeded actual growth rates obtained from inoculation studies of four cured RTE meat products (wieners, smoked-cooked ham, light bologna, and cotto salami). The final model will be useful to food technologists in determining formulations that will result in finished cured RTE meat products in which L. monocytogenes is not likely to grow.

Bermudagrass management in the Southern Piedmont USA. V: Gastrointestinal parasite control in cattle.

Parasite-free pastures would improve cattle health and performance, resulting in possible economic return to producers. Our objective was to determine the effect of a single series of anthelmintic treatment of steers prior to stocking on Coastal bermudagrass pastures, during five consecutive summers, on the parasite burden in cattle. The site for this experiment had been conventionally cropped for several decades, with no exposure to cattle, and would be expected to be relatively free of nematode larvae. The experimental design was a randomized complete block (landscape features) with a split plot arrangement of treatments where main plots were pasture fertilization treatments (mineral, clover plus mineral, and broiler litter) and split plots were low and high forage mass. Anthelmintic treatment included pour-on ivermectin on day -21, albendazole on day -7, and injectable ivermectin 48 h prior to stocking of pastures, with the cattle remaining in drylot during the 48-h period prior to being placed on the experimental paddocks. All steers received only one series of treatments during any given year. Yearling Angus steers (Bos taurus) were managed in a put-and-take grazing system with three "tester" steers assigned to each paddock and "grazer" steers added or removed at 28-day intervals. From 1994 to 1998, steers grazed the paddocks for a 140-day period from mid May until early October each year. Fecal samples for worm egg counts were obtained on day 0 and at 28-day intervals, thereafter. On all sampling days after day 0, samples were obtained only from tester animals. Over the 5-year period, the mean eggs per gram of feces (epg) gradually increased from 0 (following treatment) to a mean of 2.2 (range from 0.7 to 3.0) by the end of the grazing season (the last sampling date) in October. Although the epg were not zero, they were below threshold levels that would allow development of a parasite burden in cattle. In traditional management systems, cattle graze parasite-contaminated pastures; therefore, parasites negatively impact growth and productivity throughout the entire grazing period. Periodic anthelmintic treatments simply give a temporary reprieve from those parasitic infections. Conceptually, using the current grazing system, it should be possible to maintain these pastures in a parasite-free status indefinitely; however, from a drug resistance perspective, it would be most applicable in sod-based rotation systems where cattle graze from two to five years before land is returned to row-crops. By removing the effect of parasites, cattle can grow without the physiological constraints that gastrointestinal parasites place on appetite, digestion, nutrient utilization, and general well being.

Seasonal variation in venison quality of mature, farmed red deer stags in New Zealand.

Two studies involving 20 red deer (Cervus elaphus) stags were conducted to determine the effects of season on venison quality. In each study, five sexually mature red deer stags were slaughtered immediately preceding the rut (autumn) and five were slaughtered after the rut. Stags slaughtered postrut had lower carcass weights (25 to 30%) than those slaughtered prerut. Average bodywall thickness measurements above the 12th rib (an indicator of fat thickness) were approximately 31 mm prerut compared with 3 to 7 mm postrut. Individual muscles and retail cuts (which included subcutaneous and intermuscular fat) were heavier in prerut carcasses. There were significant decreases in intramuscular fat in both the longissimus muscle and the semimembranosus muscle. Postrut longissimus muscle steaks appeared brighter and(or) fresher than the other groups; color acceptability was negatively correlated (P less than .05) with fat content. Prerut streaks from both muscles were more tender than postrut steaks from those muscles. Overall desirability and tenderness were highly correlated (r = .94 and .82 for longissimus muscle and semimembranosus muscle, respectively).

Raising replacement beef heifers in the south-birth to parturition: a review of current practices.

The South of the United States (13 southern states) is ecologically and socioeconomically well suited for reproducing ruminant animals. The South has a broad economic base, its climate is comparatively mild, much of its soil is easily eroded requiring vegetative cover, it receives comparatively abundant rainfall, and a diversity of plant species grow well, enabling a multitude of production and management alternatives. The South currently accounts for 46.3% of the beef cows in the United States. To assess current practices associated with the raising of replacement beef heifers, a questionnaire was sent to 60 extension beef cattle specialists in the 13 southern states. Twenty-four completed questionnaires revealed that much needs to be accomplished to improve replacement heifer production. Particularly deficient areas include lack of a limited breeding season, failure to check for pregnancy, inadequate health management, poor nutrition such that heifers do not calve at 24 mo of age, and often those that calve do not rebreed. These deficiencies result in reduced economic efficiency of replacement heifer development and could result in a significant reduction in profits of an entire beef cow-calf operation. Beef cattle specialists suggested that part of the problem associated with development of replacement heifers is a lack of defined objectives by producers.

Behavior of steers grazing monocultures and binary mixtures of alfalfa and tall fescue.

Spectral analysis was used to relate dietary quality and herbage species to the behavior of grazing steers. Four .3-ha paddocks were established with either 'AU-Triumph' tall fescue (F; Festuca arundinacea Schreb.), 'Apollo' alfalfa (A; Medicago sativa L.), 1/3 fescue and 2/3 alfalfa (2/3A), or 2/3 fescue and 1/3 alfalfa (1/3A). Each paddock was stocked with 10 to 16 steers and defoliated in 5 d. Three steers on each paddock carried vibracorders to monitor grazing time. Daily forage samples were taken in 10-cm layers and weighed. Esophageal extrusa were collected from fistulated steers to measure diet quality. Daily grazing time did not differ (P = .37) among treatments; however, steers grazing mixtures grazed numerically longer (1.4 h/d) than steers on monocultures. Spectral analysis revealed that steers grazing A and 2/3A had many daily meals of short duration, but steers grazing 1/3A and F consumed three meals daily at 8-h intervals. Throughout the 4.67-d grazing period, quality of the diet linearly declined in crude protein and herbage digestibility, linearly increased in neutral detergent fiber and cellulose, and exhibited quadratic changes in lignin and ash. For most quality values, the tall fescue monoculture differed from the others (P < .05). Steers selected diets with similar quality for the A, 2/3A, and 1/3A treatments. This study illustrates how differences in forage diets alter grazing behavior of steers.

Urinary and biliary excretion of ergot alkaloids from steers that grazed endophyte-infected tall fescue.

Ergot alkaloids cause fescue toxicosis when livestock graze endophyte-infected (E+) tall fescue. Little is known about the bioavailability of the ergot alkaloid classes (lysergic acid, lysergic acid amides, or ergopeptine alkaloids) in livestock, and this hampers development of pharmacological strategies to ameliorate the toxicosis. One method used to determine bioavailability of ergot alkaloids is to examine urinary and biliary excretion patterns. Thus, our objectives were to compare ergot alkaloid excretion via urinary or biliary systems and to determine the rate of appearance or clearance of these alkaloids in cattle that were grazing E+ or endophyte-free (E-) tall fescue. In autumn 1996, bile and urine samples were collected from eight steers (203 kg), each grazing E+ and E- tall fescue, and total alkaloid excretion was quantified using competitive ELISA. Approximately 96% of the ergot alkaloids were excreted in urine. The same steers were used to examine the rate of appearance in, or clearance from, urine when switched from E+ to E-, or from E- to E+, pastures in comparison with steers that were continuously grazing E+ or E- tall fescue at 0, 2, 5, and 7 d. Steers were returned to their original pastures after 7 d, and urine was collected at 2, 5, and 7 d. Urinary alkaloid concentrations in steers switched from E- to E+ pastures were similar (P = .55) to those in steers that continuously grazed E+ tall fescue after 2 d. Steers switched from E+ to E- pastures had urinary alkaloid concentrations similar (P = .91) to those in steers that continuously grazed E- pastures after 2 d. In 1997, two trials were conducted in which steers (191 kg) were switched or remained on E+ or E- pastures, and urine was collected at 0, 12, 24, 48, and 96 h to estimate rate of alkaloid appearance or clearance. Steers switched from E- to E+ 1) had about 33% as much urinary alkaloids as steers grazing E+ pasture after 12 h, 2) were not different after 24 h (P = .76), 3) had twice those of the E+ steers at 48 h (P < .05), and 4) were not different after 96 h. Steers switched from E+ to E- tall fescue had approximately 33% less (P < .05) urinary alkaloids than those grazing E+ at 12 h, 67% less (P < .05) at 24 and 48 h, and were not different (P = .86) from steers continuously grazing E- pastures after 96 h. Urinary alkaloid excretion patterns were similar to ergot alkaloid solubility patterns from in vitro digestion of E+ tall fescue. We suggest that alkaloids, liberated from the forage by ruminal microorganisms, were rapidly absorbed as lysergic acid amides and biotransformed ergopeptine alkaloids.

Influence of packaging method and length of chilled storage on microflora, tenderness and colour stability of venison loins.

Sections of venison loins (LD) weighing approximately 300 g from 12 red deer (Cervus elaphus) were packaged using four packaging methods: (a) vacuum packaging, (b) CO(2) flushed using a nylon containment film (CO(2)-Nylon), (c) CO(2) flushed using an ultra-high barrier containment film (CO(2)-UHB), and (d) CO(2) flushed using an aluminium foil laminate containment film (CO(2)-Foil) and stored for 1, 6, 12 and 18 weeks at 0°C. Meat pH values were lower in all CO(2) flushed meat packages (P<0·05) than in vacuum packaged meat. Lactic acid bacteria and total anaerobic counts increased over storage time in all packages regardless of treatment up to values of log(10) 7·8 and 7·6 g(-1), respectively. Tenderness tended to increase as meat was stored for up to 18 weeks. Colour scores taken during simulated retail display indicated that colour deteriorated more rapidly when meat was stored for 12 and 18 weeks than for 1 and 6 weeks. Vacuum packaging and gas flushing (CO(2)-Foil) resulted in higher initial colour scores than venison packaged in the CO(2)-Nylon or CO(2)-UHB materials. Venison stored for 18 weeks also exhibited a higher proportion of packages containing off odours, lower flavour desirability and flavour intensity scores as well as higher off flavour scores than meat stored for shorter times. The implications of these effects are discussed. Although there were few significant differences in microbial growth and sensory characteristics due to packaging method or containment film, vacuum packaging appeared to be the most economic and produced meat of better colour stability.

Metabolism of decoquinate in chickens and Japanese quail.

Thirty mature chicken hens and 40 mature Japanese quail hens were used in an experiment to compare pathways of decoquinate (DQ) excretion. Labelled DQ was injected into chickens (.5 microCi via wing vein puncture) and quail (.25 microCi via cardiac puncture) on Day 0. Blood was sampled at 0, 1.5, 3, 6, 9, 12, 24, and 48 h postinjection. Eggs and excreta of chickens and quail were collected for 28 and 14 days, respectively, and analyzed for 14C. Six chickens and eight quail were sacrificed prior to 14C-DQ injection and also on Days 1, 7, 14, and 34 or 32 postinjection. Samples of liver, heart, kidney, bile, skin, fat, and muscle were analyzed for 14C. Blood rapidly cleared 14C in both species, and the half-time of 14C excretion via excreta was more rapid in quail (.37 day) than in chickens (.92 day). Little 14C was found in the eggs of quail (.32% of dose) and chickens (.17% of dose). Quail appeared to excrete peak amounts of detectable 14C 1 day earlier (Day 4) than chickens (Day 5). Liver contained the greatest concentration of 14C on Day 1 in both species. By the end of the experiment, less than 1% of the dose remained in liver or other organs. Results indicate that chickens and quail metabolize 14C-DQ at comparable rates and by similar pathways.

Dementia care creating a therapeutic milieu.

1. In dementia care, the full spectrum of interventions in a therapeutic milieu provides for safety, structure, support, involvement, and validation. 2. A safe environment accommodates wandering and compensates for physical and cognitive impairments. A therapeutic milieu provides for both physical and psychologic safety. 3. Two components of structure include the design of the physical environment and the schedule of activities. 4. The central element that defines quality in a therapeutic milieu is the dimension of interpersonal relationships.

Evaluating the ability to measure pork fat quality for the production of commercial bacon.

This study was conducted to evaluate three fat quality measures to characterize the suitability of pork bellies for commercial bacon production. Bellies from six sources (A to F) and two weight ranges (4.5/5.5 kg and 5.5/6.4 kg) were sampled by randomly selecting 50 belly sets from commercial combos of pork bellies from each source. The fat on these 50 individual bellies was assessed for quality using three methods: an FTNIR spectrophotometer to predict iodine (IV) value, a Durometer to assess fat firmness, and a subjective fat quality score (FQS) to assess integrated values of fat color, firmness, oiliness, and wetness. Data show that the fat quality measures differed (P<0.05) by pork belly source and weight class with significant interactions between the two. Bellies were subsequently manufactured into bacon and bacon slicing yield index varied significantly (P<0.05) by belly source, weight class, and their interaction. Durometer and FQS results were significantly (P<0.05) correlated with bacon slice yield. The 50 belly subsamples obtained from each source/weight class also allowed the prediction of frequency distribution-based values based on fat quality measures (proportion IV>74, proportion Durometer value <50, and proportion FQS>3. These were also correlated with slice yield. The data lead to a new paradigm model that is useful to describe both the uncertainty in fat quality measures and the relationships observed from pork bellies from different sources.

A psychosocial model of dementia care: theoretical and empirical support.

In this article, a psychosocial model of dementia care is presented from a social constructionist perspective, contrasted to the medical model, and illustrated with data from a qualitative study. In findings reported in this article, family and professional caregivers described social and psychological approaches that portray elements of specialized dementia care provided within a therapeutic social environment.

Comparative drug depletion in domestic animals and birds.

Decoquinate (Rhone-Poulenc Inc) and Narasin (Eli Lilly and Co) were selected as model drugs for a comparison of metabolism between major (cattle and chickens) and minor (sheep and quail) species. Decoquinate has been studied in all four species. Narasin studies are in progress in chickens and quail. More than 96% of injected 14C-decoquinate (DQ) was eliminated from blood of all species within 1 hr. Disappearance of the remaining 1 to 4% from blood was rapid for all species. Half-times for DQ appearance in excreta were all less than one day. Cumulative excretion of DQ in eggs of chickens and quail was about 1% for both species. Disappearance of DQ from tissues was essentially complete in 14 days. More than 80% of injected 14C-narasin was eliminated from blood within 1/2 hr. Disappearance of the remainder was rapid for both chickens and quail.

Comparative metabolism of 14C-decoquinate in chickens, quail and sheep.

Removal of pulse doses of 14C-decoquinate from blood was studied in chicken hens, quail hens, and ewe lambs. Estimated clearance before the first post-injection sample at 1 1/2 hr was 96% for sheep, 99% for chickens and over 99% for quail. Half-times for removal of the remaining radioactivity from the blood were 26.8 hr for sheep, 144.7 hr for chickens and 27.2 hr for quail. Treating the chicken data as biphasic yielded a 3.4 hr half-time for an initial fast phase and 210 hr for a later slow phase. Radioactivity disappeared from sheep blood between 2 and 7 d, from chicken blood between 7 and 14 d, and from quail blood between 1 and 2 d. Urine accounted for 35% of the radioactivity administered to sheep. It did not contain detectable activity after the third day.