The significance of clean and dirty animals for bacterial dynamics along the beef chain

Animal Welfare and Food Safety When Slaughtering Cattle Using the Gunshot Method

Simple Summary

Transporting cattle from the farm to the slaughterhouse is often stressful for the animal. With the gunshot method, it is stunned using a rifle while together with familiar herd members in an enclosure on the farm. The shot makes the animal unconscious. Then, as in normal slaughter, the animal is bled to death. Finally, it is transported to a nearby slaughterhouse. We aimed to assess the consequences for animal welfare and food safety of using the gunshot method. Twenty Hereford steers were shot with a hunting rifle using small-calibre ammunition from an elevated position and distance of 6–12 m. Each time, only one out of four to seven animals in a 16 × 10 m corral was shot. Based on the animals’ behaviour and physiological blood values, stress levels before shooting were low. Eleven animals were considered completely unconscious, while seven showed some signs of consciousness and two were poorly stunned. Two animals were reshot with heavier ammunition. Bleeding was satisfactory and little or no contamination was found on the carcasses. We conclude that the gunshot method is applicable to large beef steers while maintaining a satisfactory level of animal welfare and food safety, provided that the necessary conditions can be achieved.

Abstract

Transporting cattle from farm to slaughterhouse is often stressful for the animal, which can impair the meat quality. With the gunshot method, the animal is stunned with a rifle shot while together with familiar herd members in their home environment, exsanguinated and transported to a nearby slaughterhouse. Aiming to assess the consequences for animal welfare and food safety, 20 Hereford steers aged 18–54 months were shot with .22 Magnum ammunition from an elevated position and distance of 6–12 m. Each time, only one out of four to seven animals in a 16 × 10 m corral was shot. Dressing was done on farm. Based on the animals’ behaviour and blood concentrations of cortisol, glucose and lactate, stress levels before shooting were low. Eleven animals were deeply stunned, the consciousness of seven others was ambiguous, and two were poorly stunned. Two animals were reshot. The bleed-out was satisfactory for all animals, and little or no faecal contamination was found on the carcasses. We conclude that the gunshot method is applicable to large beef steers while maintaining a satisfactory level of animal welfare and food safety, provided that the necessary conditions can be attained.

Effects of chilling duration on USDA Quality Grade of beef carcasses

Two hundred and nine beef carcasses (BW of 361 ± 53 kg) from crossbred, grain-finished cattle were harvested in a commercial abattoir and subjected to a 96-h spray chilling treatment, conducted at 0 to 3°C in a commercial hot box with a wind speed of 3.1 m/s and 153-lux of fluorescent light. At the 24, 48, 72, and 96 h points of the treatment, the carcasses were analyzed for fatty acid composition, marbling score, core temperature (n = 1), pH, shrinkage, color, and aerobic plate count (n = 50). Carcasses reached 3ºC after 12 to 16 h of chilling. There were minimal changes in shrinkage among time point (-0.4 to 1.2%; P ≤ 0.002), pH (5.56 to 5.69; P ≤ 0.001), and aerobic plate count (APC) (0.1 to 0.7 log; P ˂ 0.001). Initial 24-h grading revealed a grade composition of 21.1% Slight (SL, n = 44), 34.0% Small (SM, n = 71), 17.2% Modest (MT, n = 37), 17.7% Moderate (MD, n = 36), and 10.1% Slightly Abundant (SA, n = 21). With marbling score in numeric values between 200 (Practically Devoid00) and 1100 (Abundant00), carcasses that had SM or greater marbling score at 24 h experienced a deduction of 34 to 60 points by the 96th hour of spray chilling (P ≤ 0.042). Comparatively, the marbling scores of the SL carcasses increased from 442 points at 24 h to 469 points at 96 h. Moreover, SL carcasses had a greater percentage of polyunsaturated fats (PUFA) (P < 0.001). Results indicate that spray chilling for 96 h may slightly increase the marbling score of USDA Select, but has minimal impacts on marbling score of greater USDA quality grades.

Beef abattoir interventions in a risk-based meat safety assurance system

In risk-based meat safety assurance system, the use of interventions is intended to accomplish the meat safety targets on chilled carcasses, particularly in situations when an abattoir is unable to sufficiently reduce risks arising from specific farms/animal batches by using process hygiene alone. Furthermore, interventions are considered whenever food safety authorities identify meat production processes associated with high risks for consumers. This paper overviews the role of beef interventions in a risk-based, meat safety assurance system. Cattle hide interventions (chemical hide washes and microbial immobilisation treatment with shellac) and beef carcass interventions (pasteurisation treatments with hot water and/or steam and organic (lactic) acid washes), show consistent reduction effects of aerobic bacteria and faecal indicators and reduced prevalences of naturally present VTEC and Salmonella. The review also identified interventions where there was a lack of data and further research was needed, and other contextual factors to inform the risk management decisions for further development of risk-based meat safety assurance system.

Cattle Cleanliness from the View of Swedish Farmers and Official Animal Welfare Inspectors

Dirty cattle have been commonly recorded in official animal welfare inspections in Sweden for years. The relevant authorities have initiated work to better understand the causes of dirty cattle, in order to improve compliance and standardize the grounds for categorizing a farm as non-compliant with welfare legislation when dirty animals are present. This study investigated the occurrence of dirty cattle in official animal welfare controls, on Swedish cattle farms, and examined farmers' views on the reasons for non-compliance and on key factors in keeping animals clean. The data used were collected by animal welfare inspectors at the county level during the regular official inspections of 371 dairy and beef cattle farms over two weeks in winter 2020. In addition to completing the usual inspection protocol, the inspectors asked farmers a set of questions relating to why their animals were clean or dirty. Dirty cattle were found on 49% of the farms inspected, but only 33% of the farms were categorized as being non-compliant with Swedish welfare legislation. According to inspectors and farmers, dirtiness in cattle depends mainly on management routines, which is a promising result since routines can be improved. The results also revealed a need for better guidance for inspectors and farmers on when dirtiness should be categorized as non-compliance with animal welfare legislation.

Microbiological Testing for the Proper Assessment of the Hygiene Status of Beef Carcasses

Microbiological testing is an important quality management tool in the food industry. In this study, the hygiene status of beef carcasses sampled in eight Brazilian slaughterhouses was assessed by enumeration of different hygiene indicator microorganisms, and a model to establish potential associations among these counts was proposed. The carcasses (n = 464) were surface sampled at four slaughtering steps (step 1: Hide after bleeding; step 2: Carcass after hide removal; step 3: Carcass after evisceration; step 4: Carcass after end washing) and subjected to a counting of mesophilic aerobes (MA), Enterobacteriaceae (EB), total coliforms (TC), and Escherichia coli (EC) using Petrifilm™ plates. Among the sampled beef carcasses (step 4), 32 (6.9%) and 71 (15.3%) presented counts above the microbiological criteria established by (EC) No. 1441/2007 for MA and EB, respectively. Thus, indicating that improvements in slaughter hygiene and a review of process controls are demanded in some of the studied slaughterhouses. The log count differences of EC, TC, and EB from MA were considered as response variables as a function of the slaughtering steps. Differential log counts changed consistently with the steps. The measurements, including the patterns in their inherently random variability, were fairly predictable from steps 1 and 4. The results indicated that differential log counts for TC and EC are not relevant, as their concentrations and random pattern can be inferred from counts of MA and EB. The proposed model can be used as a valuable tool for the design and adoption of feasible quality control programs in beef industries. The adoption of such a tool should have a positive contribution on consumers’ health and enhance product quality.

A comparison of two evisceration methods on hygienic quality in the pelvic area of sheep carcasses

The aim was to compare the effects of two evisceration methods under operational conditions, on the pelvic hygiene of sheep carcasses. Method 1: rectum sealed with plastic bag and pushed through the pelvic cavity. Method 2: rectum cut, placed back inside and pulled out from the carcass. The 18 largest Norwegian sheep abattoirs participated. Sampling areas were i) 400cm² inside the pelvic cavity (n=623), ii) 100cm² outside the circum-anal incision (n=622). There were pooled samples by swabbing the same area of five carcasses, representing totally 3115 carcasses. Mean E. coli results from Method 1: -1.61logCFU/cm² inside and -0.25logCFU/cm² for the outside area. Results from Method 2: -1.56logCFU/cm² inside and -0.42logCFU/cm² outside. There were no significant differences between the two methods. Both evisceration methods can produce carcasses that are of practically identical high hygienic quality.