The EC decision of the 8th June 2001 (EC/471/2001): excision versus swabbing

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.

Impact of sampling area and location on measurement of indicator organisms during beef carcass interventions

The effect of the sponge sample collection site on the recovery of multiple indicator organisms from beef carcass surfaces was evaluated to simplify and validate our previous sampling method for ease of implementation as a general protocol. Sponge samples were collected at three beef processing plants using hot water or acidic antimicrobials as interventions. Two 4,000-cm(2) samples were collected from preevisceration carcasses (n = 248), one from the inside and outside round area (top site) and one from the navel-plate-brisket-foreshank area (bottom site). One-half of the samples (n = 124) were collected before a wash cabinet intervention and the other half after the intervention. The numbers of total aerobic bacteria, Enterobacteriaceae, coliforms, and Escherichia coli were determined for one-half of each individual sponge sample. The other halves of the sponges were combined to represent a top plus bottom 8,000-cm(2) SAMPLE: For the preintervention carcasses, 4,000-cm(2) samples collected from the top or bottom sites of the carcasses were not significantly different (P > 0.05) from each other or from the 8,000-cm(2) combined sample in recovery of the indicator organisms. Significant reductions of indicator organisms were observed in all three types of sponge samples after intervention; however, samples collected from the bottom site recovered less organisms (P < 0.05) compared with samples of the other types. These results suggested that samples collected from either the top or the bottom site of the carcasses with this method are suitable for monitoring indicator organisms as long as the same sampling site is consistently used.

Microbiological Sampling of Carcasses by Excision or Swabbing with Three Types of Sponge or Gauze

Fifty-five bovine, 50 equine, 60 ovine, and 50 porcine carcasses were sampled in a slaughterhouse in eastern Spain. Two samples were taken from each carcass, one using the excision method and the other using the swabbing method. Four different materials were used for swabbing: cellulose, polyurethane, or viscose sponges, and medical gauze. Samples were collected at the end of the process by four different people before the carcasses were taken to the cooler. The samples were examined for total viable bacteria counts (TVCs) and Enterobacteriaceae counts (ECs). The mean TVC for all species sampled by excision was 4.50 log CFU/cm2, which was significantly higher than the 3.53 log CFU/cm2 obtained by swabbing. The TVCs obtained using gauze and the cellulose and polyurethane sponges were significantly higher (P &lt; 0.05) than the corresponding TVCs obtained using viscose sponges. Animal species, the person who collected the samples, and microbiological load also had a significant effect on TVC. ECs were obtained from 82.8% of excision samples, from larger percentages of samples obtained using cellulose or polyurethane sponges or gauze swabs, but from smaller percentages of samples obtained using viscose sponges. The Enterobacteriaceae load significantly influenced the EC. In contrast, animal species and the person who collected the samples had no significant effect. The cellulose sponge, polyurethane sponge, and gauze gave high mean log counts of aerobic bacteria and Enterobacteriaceae, which makes these swab types suitable for use in slaughterhouses for the purpose of assessing production process hygiene.

Microbiological sampling of swine carcasses: A comparison of data obtained by swabbing with medical gauze and data collected routinely by excision at Swedish abattoirs

Swab sample data from a 13-month microbiological baseline study of swine carcasses at Swedish abattoirs were combined with excision sample data collected routinely at five abattoirs. The aim was to compare the numbers of total aerobic counts, Enterobacteriaceae, and Escherichia coli, recovered by swabbing four carcass sites with gauze (total area 400 cm2) with those obtained by excision at equivalent sites (total area 20 cm2). The results are considered in relation to the process hygiene criteria that are stated in Commission Regulation (EC) No 2073/2005. These criteria apply only to destructive sampling of total aerobic counts and Enterobacteriaceae, but alternative sampling schemes, as well as alternative indicator organisms such as E. coli, are allowed if equivalent guarantees of food safety can be provided. Swab sampling resulted in higher mean log numbers of total aerobic counts at four of the five abattoirs, compared with excision, and lower or equal standard deviations at all abattoirs. The percentage of swab and excision samples positive for Enterobacteriaceae at the different abattoirs ranged from 68 to 100% and 15 to 24%, respectively. Similarly, the percentages of swab samples that were positive for E. coli were higher than the percentages of positive excision samples (range 52 to 84% and 3 to 14%, respectively). Due to the low percentage of positive excision results, the mean log numbers of Enterobacteriaceae and E. coli were only compared at two and one abattoirs, respectively, using log probability regression to substitute censored observations. Higher mean log numbers of Enterobacteriaceae were recovered by swabbing compared with excision at one abattoir, whereas the numbers of Enterobacteriaceae and E. coli did not differ significantly between sampling methods at one abattoir. This study suggests that the same process hygiene criteria as those stipulated for excision can be used for swabbing with gauze without compromising food safety. For monitoring of low numbers of Enterobacteriaceae and E. coli, like those found on swine carcasses at Swedish abattoirs, the results also show that swabbing of a relatively large area is superior to excision of a smaller area.

An in vitro system for the comparison of excision and wet-dry swabbing for microbiological sampling of beef carcasses

An in vitro system for the comparison of wet-dry swabbing and surface tissue excision was developed to ascertain whether the commonly accepted statement of the advantage (in terms of bacterial recovery) of the tissue excision method is also legitimate when different kinds of bacteria are used. A total of 1,770 sections (2.5 by 10 cm) of bovine skin were individually inoculated on the subcutaneous fat side by spreading various suspensions of marker organisms (nalidixic acid-resistant Escherichia coli, vancomycin-resistant Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus) at different concentrations and sampled by two standard methods: cotton wet-dry swabbing and excision. Most counts from cuts sampled by excision were significantly (P < 0.05) higher than the wet-dry swabs; however, no differences were observed between the control and the sampling method when sections were inoculated with bacterial solutions at a concentration of 10(3) CFU/ml and sampled by excision. For sections inoculated with bacterial solutions at a concentration of 10(3) CFU/ml, counts given as log CFU/25 cm2 ranged from 1.97 (S. aureus sampled by wet-dry swab) to 3.06 (S. aureus sampled by excision). For sections inoculated at a concentration of 10(4), counts given as log CFU/25 cm(2) ranged from 2.15 (E. faecalis sampled by wet-dry swab) to 3.19 (S. aureus sampled by excision). For sections inoculated at 10(5), counts given as log CFU/25 cm(2) ranged from 2.94 (E. faecalis, wet-dry swab) to 3.98 (S. aureus, excision), and for sections inoculated at 106, counts given as log CFU/25 cm(2) ranged from 3.53 (E. coli, wet-dry swab) to 4.69 (S. aureus, excision). The proposed system, which enabled a considerable amount of samples to be analyzed under controlled experimental conditions and a large number of data to be generated in a short time, demonstrated among the tested microorganisms that whereas the excision method recovered the highest number of bacteria, control means were always (with the exception of an inoculum of 10(3)/ml) significantly higher than means from either of the sampling methods. Our results indicate that particular attention should be paid to the diverse microflora that can contaminate carcasses in a given slaughterhouse and that it is not appropriate to generalize by saying that the destructive method is the reference technique for the bacteriological sampling of carcasses in slaughterhouses, especially when the contamination is higher than 10(3) CFU/25 cm(2).

Excision vs sponge swabbing - a comparison of methods for the microbiological sampling of beef, pork and lamb carcasses

AIMS

The aim of this research was to compare excision sampling with polyurethane and cellulose acetate sponge swabbing for the recovery of total viable counts and Enterobacteriaceae on meat carcasses.

METHODS AND RESULTS

Two sample types were used to compare the methods: (i) individual samples, taken from four sites on each carcass and (ii) composite samples, created by pooling the samples from four sites from an additional set of carcasses. When the polyurethane sponge and excision method were compared for individual sites, there were no significant differences in bacterial recovery on beef and pork carcasses and on two of four sites on lamb carcasses. However, when samples from each site were pooled, the excision method was more efficient than either swabbing method across the three animal species.

CONCLUSIONS

Sampling using the polyurethane sponge represents an equivalent alternative method to excision for the bacteriological sampling of carcass surfaces which is nondestructive and less labour intensive.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides the scientific basis for using sponge swabbing instead of excision in compliance with 2001/471/EC.

Microbiological carcass sampling methods to achieve compliance with 2001/471/EC and new hygiene regulations

The aim of this research was to evaluate the effectiveness of excision versus swabbing as methods for the assessment of bovine and ovine carcass hygiene. Microbiological evaluation of bovine and ovine carcasses was performed by obtaining total viable counts (TVCs) and total Enterobacteriaceae counts (TECs) using excision and a swab (polyurethane) sampling method. Four anatomical locations were sampled on 30 bovine and 30 ovine carcasses, processed in four small (<10 animals per week) abattoirs. Excision and swab TVC were statistically similar (P<0.05) at all sites. The corresponding TECs were also statistically the same (P<0.05). Swabbing with the polyurethane sponge was therefore as effective as excision sampling for the determination of TVCs and TECs on bovine and ovine carcasses and may be used instead of excision sampling when assessing bovine and ovine carcass hygiene as per 2001/471/EC.

Sampling methods for microbiological analysis of red meat and poultry carcasses

Microbiological analysis of carcasses at slaughterhouses is required in the European Union for evaluating the hygienic performance of carcass production processes as required for effective hazard analysis critical control point implementation. The European Union microbial performance standards refer exclusively to the excision method, even though swabbing using the wet/dry technique is also permitted when correlation between both destructive and nondestructive methods can be established. For practical and economic reasons, the swab technique is the most extensively used carcass surface-sampling method. The main characteristics, advantages, and limitations of the common excision and swabbing methods are described here.