Decontamination of cattle hides prior to slaughter using washes with and without antimicrobial agents

Two trials were conducted to determine the efficacy of cattle wash treatments in reducing pathogens on hides of cattle before slaughter. In trial I, live cattle (n = 120) were washed in an automated, commercial cattle wash system with one of four treatments (single water wash, double water wash, water wash with 0.5% L-lactic acid, or water wash with 50 ppm chlorine). Samples were collected at three locations (brisket, belly, and inside round) pre- and posttreatment to evaluate the effectiveness of treatments on the reduction of aerobic plate counts, coliforms, Escherichia coli and the incidence of Salmonella. For all three locations, bacterial numbers increased from 0.1 to 0.8 log CFU/cm2 posttreatment. In trial II, hide samples were inoculated in the laboratory with 6.0 log CFU/cm2 of rifampicin-resistant Salmonella serotype Typhimurium. Hide wash treatments included higher concentrations of chlorine (100, 200, and 400 ppm) and L-lactic acid (2, 4, and 6%), as well as other antimicrobial agents such as ethanol (70, 80, and 90%), acetic acid (2, 4, and 6%), and Oxy-Sept 333 (0.5, 2, and 4%). Spray wash treatments with ethanol and 4 to 6% concentrations of lactic acid had greater (P < 0.05) mean log reductions than 2% solutions of acetic or lactic acid, as well as 100, 200, and 400 ppm chlorine and the control water wash treatment. Spray wash treatments with Oxy-Sept 333 and 100, 200, or 400 ppm chlorine were not effective (P > 0.05) in reducing Salmonella Typhimurium compared to the (control) distilled water spray wash treatment. Several effective cattle hide interventions were identified in a controlled laboratory setting, but the high concentrations required for effectiveness would likely present problems from an animal welfare standpoint.     

Treatment of cattle hides with Shellac solution to reduce hide-to-beef microbial transfer

The hide-to-beef microbial transfer-reducing effects of a novel Shellac treatment of hides (based on "on-hair immobilization" of microorganisms) were evaluated. In the hide-to-meat direct contact laboratory-based experiments, treatment of hides (of varying visual cleanliness) with Shellac produced significant microbial reductions on beef: up to 3.6 log(10) CFU/cm(2) of total viable count of bacteria (TVC), up to 2.5 log(10) CFU/cm(2) of Enterobacteriaceae (EC) and up to 1.7 log(10) CFU/cm(2) of generic Escherichia coli (GEC). In a small commercial abattoir under "bad-case" conditions (slaughtering dirty cattle, inadequate process hygiene), treatment of hides with Shellac produced significant microbial reductions on beef carcasses: 1.7 log(10) CFU/cm(2), 1.4 log(10) CFU/cm(2) and 1.3 log(10) CFU/cm(2) of TVC, EC and GEC, respectively. In both laboratory- and abattoir-based trials, TVC reductions on beef achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ significantly between the two hide treatments.     

牛皮和绵羊皮二氧化碳脱灰工艺的新探索

目前,世界上已经有许多制革企业将二氧化碳用于制革脱灰,由于这种脱灰方法耗费的时间略长一些,因     

Studies to evaluate chemicals and conditions with low-pressure applications for reducing microbial counts on cattle hides

Studies were conducted to identify effective antimicrobials and application parameters that could be used as decontamination interventions to reduce microbial loads on cattle hides before removal from carcasses. In study I, hide swatches inoculated with Escherichia coli O157:H7 were sprayed with 10% acetic acid (at 23 and 55 degrees C), 10% lactic acid (at 23 and 55 degrees C), 3% sodium hydroxide (at 23 degrees C) or 4 and 5% sodium metasilicate (at 23 degrees C). All antimicrobials were evaluated independently after being applied alone, being applied after a water rinse, or being followed by a water rinse. Antimicrobial treatments followed by a water rinse lowered E. coli O157:H7 populations by 0.6 to 2.4 log CFU/cm2 and resulted in hides with a surface pH of 6.3 to 9.2. Treatments in which a water rinse was followed by antimicrobial application lowered E. coli O157:H7 populations by 1.5 to 5.1 log CFU/cm2 but resulted in hides with a surface pH of 3.9 to 10.5. In study II, whole hides were treated with one of four antimicrobials (acetic acid, lactic acid, sodium hydroxide, or sodium metasilicate) followed by a water rinse. Hides were evaluated for aerobic bacterial counts, total coliform counts, and E. coli counts. Generally, all antimicrobials resulted in greater reductions (P < 0.05) of E. coli counts when compared with the control; however, only acetic and lactic acids resulted in greater reductions (P < 0.05) of aerobic bacterial counts and total coliform counts compared with the controls. These antimicrobials could be used to reduce microbial contamination on hides, potentially reducing microbiological contamination transferred to carcasses or to the plant environment.     

Efficacy of ozonated and electrolyzed oxidative waters to decontaminate hides of cattle before slaughter

The hides of cattle are the primary source of pathogens such as Escherichia coli O157:H7 that contaminate preevisceration carcasses during commercial beef processing. A number of interventions that reduce hide contamination and subsequent carcass contamination are currently being developed. The objective of this study was to determine the efficacy of ozonated and electrolyzed oxidizing (EO) waters to decontaminate beef hides and to compare these treatments with similar washing in water without the active antimicrobial compounds. Cattle hides draped over barrels were used as the model system. Ozonated water (2 ppm) was applied at 4,800 kPa (700 lb in2) and 15 degrees C for 10 s. Alkaline EO water and acidic EO water were sequentially applied at 60 degrees C for 10 s at 4,800 and 1,700 kPa (250 lb in2), respectively. Treatment using ozonated water reduced hide aerobic plate counts by 2.1 log CFU/100 cm2 and reduced Enterobacteriaceae counts by 3.4 log CFU/100 cm2. EO water treatment reduced aerobic plate counts by 3.5 log CFU/100 cm2 and reduced Enterobacteriaceae counts by 4.3 log CFU/100 cm2. Water controls that matched the wash conditions of the ozonated and EO treatments reduced aerobic plate counts by only 0.5 and 1.0 log CFU/100 cm2, respectively, and each reduced Enterobacteriaceae counts by 0.9 log CFU/100 cm2. The prevalence of E. coli O157 on hides was reduced from 89 to 31% following treatment with ozonated water and from 82 to 35% following EO water treatment. Control wash treatments had no significant effect on the prevalence of E. coli O157:H7. These results demonstrate that ozonated and EO waters can be used to decontaminate hides during processing and may be viable treatments for significantly reducing pathogen loads on beef hides, thereby reducing pathogens on beef carcasses.     

An evaluation of the humaneness of puntilla in cattle

Slaughter by puntilla followed by neck sticking was examined in 309 cattle, to assess the humaneness of this method. After the neck stab, brain and spinal function as well as presence of selected cognitive responses were measured. In addition breed, sex, live weight, body condition score, number of stabs given and level of experience of the slaughterman were recorded. Repeat stabbing was needed to penetrate the foramen ovale in 24% of the animals, and was significantly less frequent in slaughtermen who were experienced, and more frequent in heavy weight animals (>380 kg). Prevalence of brain and spinal function was 91%. When animals attempted to stand after the neck stab they were more likely to have rhythmic breathing, positive palpebral response and responsiveness to threat, noise and short air stimulus. These findings indicate that nerve pathways are often functional after neck stab and therefore it is highly likely that the animals are still conscious.     

The efficacy of pulsed ultrahigh current for the stunning of cattle prior to slaughter

We present results from the development of a new system of reversible electrical stunning of cattle. A single-pulse ultra-high current (SPUC) was generated from a capacitance discharge current spike of at least 5000 V at 70 A, for approximately 50 ms. Ninety-seven cattle were stunned in three experimental protocols. With improvements made to the design of the stun box and charge delivered, 38 cattle were either stunned and immediately jugulated or monitored for signs of reappearance of brain stem reflexes at which point a concussion stun was administered. This use of the SPUC charge, provided as a biphasic-pulse waveform, resulted in a high level of stunning efficacy, with unconsciousness lasting for up to 4 min. These results were supported by EEG data taken from a subsequent cohort of stunned cattle. The SPUC stun also apparently eliminated post-stun grand mal seizures that can occur following short-acting conventional electrical stun, with its associated negative consequences on operator safety and meat quality.     

Impact of reducing the level of wet distillers grains fed to cattle prior to harvest on prevalence and levels of Escherichia coli O157:H7 in feces and on hides

Cattle fed finishing diets with wet distillers grains with solubles (WDGS) have been shown to harbor increased Escherichia coli O157:H7 populations in the feces and on the hides. To determine if feeding a lower level of WDGS at the end of the feeding period reduces E. coli O157:H7 load at harvest, 608 heifers were sorted into one of five treatments and fed 0, 40, or 70% WDGS (dry matter basis). For three of the treatments, WDGS was reduced midway through the study. Treatment 0W0W heifers (positive control) were fed a corn grain-based diet continuously, and 40W40W heifers (negative control) were fed 40% WDGS continuously. Heifers subjected to treatments 40W0W, 40W15W, and 70W15W were fed either 40 or 70% WDGS for the first 56 days and switched to 0 or 15% WDGS, respectively, for the last 56 days. Prior to the switch in diets, animals fed diets with 40 or 70% had higher prevalence and percent enumerable fecal samples for E. coli O157:H7. After the dietary switch, animals fed 40W0W, 40W15W, and 70W15W diets had fecal prevalence and percent enumerable samples (33.4 and 6.3%, 31.0 and 9.7%, and 34.9 and 8.4%, respectively) similar to those of animals fed 0W0W diets (10.2 and 3.2%, respectively; P > 0.05), whereas animals fed 40W40W had the highest fecal prevalence and percent enumerable samples (70.1 and 29.2%, respectively; P < 0.05). Similar relationships between the treatments were observed for hide samples. Time after dietary switch was important, as animals fed lower levels had significantly lower fecal prevalence and percent enumerable samples after 56 days, but not after 28 days. The study indicates that cattle can be switched to lower levels of dietary WDGS (15% or less) 56 days prior to harvest to significantly reduce E. coli O157:H7 in feces and on hides.     

Microbial populations on animal hides and beef carcasses at different stages of slaughter in plants employing multiple-sequential interventions for decontamination

Multiple-sequential interventions were applied commercially to reduce beef carcass contamination in eight packing plants. The study evaluated microbial populations on animal hides and changes in carcass microbial populations at various stages in the slaughtering process. Sponge swab samples yielded mean (log CFU/100 cm2) total plate counts (TPC), total coliform counts (TCC), and Escherichia coli counts (ECC) on the exterior hide in the ranges of 8.2 to 12.5, 6.0 to 7.9, and 5.5 to 7.5, respectively, while corresponding contamination levels on carcass surfaces, after hide removal but before application of any decontamination intervention, were in the ranges of 6.1 to 9.1, 3.0 to 6.0, and 2.6 to 5.3, respectively. Following the slaughtering process and application of multiple-sequential decontamination interventions that included steam vacuuming, pre-evisceration carcass washing, pre-evisceration organic acid solution rinsing, hot water carcass washing, postevisceration final carcass washing, and postevisceration organic acid solution rinsing, mean TPC, TCC, and ECC on carcass surfaces were 3.8 to 7.1, 1.5 to 3.7, and 1.0 to 3.0, respectively, while corresponding populations following a 24 to 36 h chilling period were 2.3 to 5.3, 0.9 to 1.3, and 0.9, respectively. The results support the concept of using sequential decontamination processes in beef packing plants as a means of improving the microbiological quality of beef carcasses.     

An evaluation of the seasonality of veterinary treatments for lameness in UK dairy cattle

Of the 4 main diseases causing lameness in UK dairy cattle, 2 (digital dermatitis and foul-in-the-foot, or interdigital necrobacillosis) are infectious diseases that are commonly associated with similar underfoot conditions, and 2 (sole ulcer and white-line disease) result from subclinical laminitis. Comparison of the seasonality of these 2 diseases can identify whether their own unique risk factors are more important than the risk factors they share. Using a database from 46 veterinarians distributed across the United Kingdom, the seasonality of treatments for these 4 diseases was evaluated. This analysis showed that the seasonality of lameness in UK dairy cattle was significantly reduced in comparison with previous reports from the 1980s. This was primarily due to 1) a reduction in the seasonality of digital dermatitis (outbreaks of which accounted for 6.7% of veterinary reports), with only 60% of reports during the winter as opposed to 72% in earlier studies, and 2) a change in the seasonality of white-line disease from a disease that was most commonly seen in the winter (55% of reports) to a disease that was most commonly reported in the late summer or early autumn, with significantly more reports in August and October than in February. Comparison of the seasonality of digital dermatitis and foul-in-the-foot showed a significant difference in the seasonality of the 2 diseases, with foul-in-the-foot being significantly more common compared with digital dermatitis in June and August. This implies that significant risk factors exist for digital dermatitis that are not as important for foul-in-the-foot. The difference in the seasonality of sole ulcer and white-line disease was even more marked, with white-line disease being significantly more common than sole ulcer from August to October, despite these diseases being more closely linked in the literature than digital dermatitis and foul-in-the-foot. This comparison shows that the seasonality of lameness has changed in the United Kingdom and that white-line disease has significantly different risk factors than sole ulcer.     

Differences among methods to validate genomic evaluations for dairy cattle

Two methods of testing predictions from genomic evaluations were investigated. Data used were from the August 2006 and April 2010 official USDA genetic evaluations of dairy cattle. The training data set consisted of both cows and bulls that were proven (had own or daughter information) as of August 2006 and included 8,022, 1,959, and 1,056 Holsteins, Jerseys, and Brown Swiss, respectively. The validation data set consisted of bulls that were unproven as of August 2006 and were proven by April 2010 with 2,653, 411, and 132 Holsteins, Jerseys, and Brown Swiss for the production traits. Method 1 used the training animal's predicted transmitting ability (PTA) from August of 2006. Method 2 used the training animal's April 2010 PTA to estimate single nucleotide polymorphism effects. Both methods were tested using several regressions with the same validation animals. In both cases, the validation animals were tested using the deregressed April 2010 PTA. All traits that had genomic evaluations from the official USDA April 2010 genetic evaluations were tested. Results included bias, differences from expected regressions (calculated using selection intensities), and the coefficients of determination. The genomic information increased the predictive ability for most of the traits in all of the breeds. The 2 methods of testing resulted in some differences that would affect interpretation of results. The coefficient of determination was higher for all traits using method 2. This was the expected result as the data were not independent because evaluations of the validation bulls contributed to their sires’ evaluations. The regression coefficients from method 2 were often higher than the regression coefficients from method 1. Many traits had regression coefficients that were higher than 2 standard deviations from the expected regressions when using method 2. This was partially due to the lack of independence of the training and validation data sets. Most traits did have some level of bias in the prediction equations, regardless of breed. The use of method 1 made it possible to evaluate the increased accuracy in proven first-crop bull evaluations by using genomic information. Proven first-crop bulls had an increase in accuracy from the addition of genomic information. It is advised to use method 1 for validation of genomic evaluations.     

An evaluation of Brix refractometry instruments for measurement of colostrum quality in dairy cattle

Acquisition of high quality colostrum is an important factor influencing neonatal calf health. Many methods have been used to assess the Ig concentration of colostrum; however, improved, validated evaluation tools are needed. The aims of this study were to evaluate both optical and digital Brix refractometer instruments for the measurement of Ig concentration of colostrum as compared with the gold standard radial immunodiffusion assay laboratory assessment and to determine the correlation between Ig measurements taken from fresh and frozen colostrum samples for both Brix refractometer instruments. This research was completed using 288 colostrum samples from 3 different farms. It was concluded that the optical and digital Brix refractometers were highly correlated for both fresh and frozen samples (r = 0.98 and r = 0.97, respectively). Correlation between both refractometer instruments for fresh and frozen samples and the gold standard radial immunodiffusion assay were determined to be very similar, with a correlation coefficient between 0.71 and 0.74. Both instruments exhibited excellent test characteristics, indicating an appropriate cut-off point of 22% Brix score for the identification of good quality colostrum.     

Failure of cortisol injected prior to milking to inhibit milk ejection in dairy cattle

To test the potential for cortisol to inhibit milk ejection directly, 18 Holstein cows were divided equally into control and treatment groups based on milk yields. For treated animals, a single injection of cortisol was made into the saphenous vein 15 min before milkings. Increasing amounts of cortisol (0, 25, 50, and 100 mg) were injected for one morning and one evening milking, with the exception that the treated cows received only one 100 mg injection. Control animals received injections of 0.9% (w/v) NaCl. Cortisol injections had no effect on milk yields. However, a potential inhibitory mechanism might involve a delay, perhaps due to the necessity of synthesizing a regulatory protein. Therefore, to test the potential for increased cortisol over a period of hours to inhibit milk ejection, six of the nine cows in the treatment group were injected with 100 mg of cortisol at 3.25, 2.25, 1.25 and 0.25 h before sequential morning and evening milkings. In blood samples taken 1 min before and after injections, base-line cortisol concentrations averaged 10.2 mg/ml; after injection they were 984.1 ng/ml, and before subsequent injections they were 37.6 ng/ml. Again cortisol injections had no effect on milk yields.     

Spread of marker bacteria from the hides of cattle in a simulated livestock market and at an abattoir

The spread of microbial contamination on the hides of beef was investigated at two stages in the meat chain: (i) in a simulated livestock market ("the market") using 33 animals, and (ii) in the unloading-to-skinning area of a commercial abattoir using 18 animals. At both stages, harmless bacterial markers (nalidixic acid-resistant Escherichia coli K-12; rifampicin- and nalidixic acid-resistant Pseudomonas fluorescens; and a tetracycline-resistant E. coli) were inoculated on the hides of a small number of selected animals, and their transfer to other animals and the environment was examined. At the market, the initial prevalence of animals positive for the hide markers (9.1% in each phase) introduced in the presale pen, sale ring, and postsale pen changed to 39.4, 15.1, and 54.5%, respectively, by the end of the market process. In addition, widespread contamination of the market environment with the hide markers was observed. At the abattoir, the initial prevalence of animals positive for the hide marker (11.1%) inoculated at unloading increased to 100% (hide before skinning) and 88.8% (skinned carcass). In addition, another marker inoculated on environmental surfaces in lairage pens, races, and stunning box was detected on 83.3% (hide before skinning) and 88.8% (skinned carcass). These results, although obtained with a relatively small number of animals, demonstrate that both the livestock market process and the unloading-to-skinning process at abattoirs can facilitate the extensive spread of microbial contamination on hides not just within, but also between, batches of animals.     

An evaluation of methods for inoculating Listeria monocytogenes into butter for microbiological experimentation

The behaviour of Listeria monocytogenes Scott A was assessed when inoculated into butter using six different methods. The butter was made using a laboratory-scale butter churn to give consistency in the butter ingredients. No increase in count was seen using the 'stab' or 'contact' methods of butter inoculation. No inoculation method was found to be ideal for every inoculation experiment that may be required. However, it was concluded that the 'mix' and 'bead' methods were most appropriate if the 'cream' inoculation method could not be used.     

Effect of feeding silages from corn hybrids selected for leafiness or grain to lactating dairy cattle

Three corn hybrids were harvested as silage and fed to lactating dairy cows to determine performance and digestibility differences between hybrids. Corn hybrids were a grain type, a generic blend, and a leafy type. Starch content of the grain, blend, and leafy silage hybrids was 26.1, 23.8, and 23.5%, respectively. In vitro digestible dry matter of the leafy hybrid silage (69.2%) was higher than the grain (66.8%) or blend (66.7%) hybrid silage. Sixty-two Holstein cows (39 primiparous and 23 multiparous) were fed diets containing (dry matter basis) 40.6% of one of the corn silages, 10.2% alfalfa haylage, 23.5% corn grain, 7.4% whole-fuzzy cotton-seed, 13.8% protein concentrate, and 4.5% vitamin and mineral mix. Cows were assigned to their silage treatment diet 3 d after parturition and remained on the diet until wk 22 of lactation. Dry matter intake, milk yield, and milk components did not differ for cows fed the grain, leafy, or generic blend silage diets for either parity group. Digestibilities of dry matter, organic matter, and neutral detergent fiber, and rate of passage were not different across the silage diets for either parity. Multiparous cows receiving the blend silage diet lost more weight throughout the 22-wk study than did cows on the leafy or grain silage diets. Primiparous cows receiving the blend silage diet spent more time eating than cows on either the grain or leafy silage diet. Time spent chewing did not differ among hybrids. Corn hybrid at 40% of dietary dry matter as silage did not have a major impact on dairy cattle performance in this trial.     

Food quality certification: An approach for the development of accredited sensory evaluation methods

The standardization and accreditation of sensory quality evaluation methods is a pressing need for the certification of food products, particularly for foods and beverages with specific sensory characteristics, such as those with a protected designation of origin (PDO). This study describes a proposal for the development of accredited sensory evaluation methods, showing as an example an application from a specific certified product (PDO Idiazabal cheese). A training and qualification process for expert panelists is required. In cheese, panelists score quality of overall sensory parameters (shape, rind, paste colour, eyes, odour, texture, flavour and aftertaste) on a scale, based on how close the product lies to a specific quality standard. Panelists justify the quality scores given on the basis of the absence/presence of specific characteristics in the product and/or the presence of defects. Training requires the prior establishment of references for both characteristics and defects. Qualification trials determine whether or not the expert panelists (both individually and as a panel) are appropriately qualified to carry out the sensory evaluation. This work also shows the quality control maintenance of qualifications for the expert panellist. This approach could be generalized to any type of food and beverage as a reference for the accreditation of sensory quality evaluation methods according to ISO 17025. In this way, each product manufacturer would be able to define its quality standard and, on the basis of this standard, carry out the sensory evaluation using a panel specifically trained for this purpose.     

Economic feasibility evaluation of microfiltration of milk prior to cheesemaking

A nonlinear programming optimization model was used to evaluate the net revenues and potential profit-ability of microfiltration (MF) prior to cheesemaking in the 3-year period 1998 to 2000, using monthly milk price and composition data. The model identifies the optimal mix of milk resources and determines if MF cheesemaking produces a higher net revenue than conventional cheesemaking that uses NDM and condensed milk for fortification. This study demonstrates the potential of this model to evaluate new technologies in cheese manufacture and improve decision making in the cheese industry. The use of MF produced higher net revenues in 30 out of the 36 mo for both Cheddar and low-moisture, part-skim mozzarella, leading to an appreciable increase in net revenue (vs. conventional cheesemaking) for both cheeses. The benefit from MF in net revenue was greater when the cream price was high. The use of 3X MF yielded the same net revenue as 2X MF. An estimate of manufacturing costs of MF vs. conventional cheesemaking was also made. To this end, the yields of products were calculated by the optimization model, while the production cost of each product was estimated from data of two economic engineering studies and a MF cheesemaking trial. The manufacturing cost of MF Cheddar was slightly higher than the manufacturing cost of conventional Cheddar. However, the benefit in net revenue from the use of MF was estimated to be higher than the difference in manufacturing costs. Moreover, some advantages in the new coproducts of MF Cheddar could outweigh its higher manufacturing cost. The relationships between prices and recoveries of coproducts required to render MF profitable were identified.