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Journal of Food Protection, Vol. 70, No. 12, 2007, Pages 2906–2910 Copyright ᮊ, International Association for Food Protection

Reseach Note Fate of Sympathetic Trunk Ganglia after Cutting in German Meat Plants

K. PISKE,1 G. ARNDT,2 S. BUDA,3 K.-D. BUDRAS,3 T. EGGERS,1 AND R. FRIES1*

1Institute of Meat Hygiene and Technology, 2Institute of Biometrics and Data Processing, and 3Institute of Veterinary Anatomy, Faculty of Veterinary Medicine, Freie Universita¨t of Berlin, Oertzenweg 19b, D 14163 Berlin, Germany Downloaded from http://meridian.allenpress.com/jfp/article-pdf/70/12/2906/1678262/0362-028x-70_12_2906.pdf by guest on 02 October 2021 MS 06-509: Received 28 September 2006/Accepted 8 August 2007

ABSTRACT

To minimize risks from pathogenic prion proteins, particular tissues from bovines and other ruminants have been declared specified risk materials (SRMs), which are required to be removed from the food chain. However, in particular for the sympathetic trunk (ST) as a part of the autonomous nervous system (ANS), which represents a potential transfer route for abnormal prion proteins (PrPSc), this is not the case. Consequently, its destination during cutting procedures deserves attention. In this survey, the handling of the ST in beef cutting plants was recorded during ongoing work. To ease these observations, the ST was separated into five parts, and eight destinations for cuts were identified. By means of an observation sheet, the destination of the respective tissue was recorded. About one-third of the ST went into human consumption, another one-third was disposed of as SRMs, and the last one-third was used for nonfood purposes or disposed of. The rear thoracic and primarily remained naturally connected to the bones going as SRMs. The stellate, front thoracic, and lumbar ganglia went in a different percent into the food chain. Frequently, workers in the same plant decided differently, even from case to case, on the destination of the tissue, which indicates a lack of standardization.

In the European Union, Regulation (EC) 999/2001, as splanchnici minores) (12–16, 19), sympathetic trunk (ST) amended, identifies specified risk materials (SRMs), which ganglia (or paravertebral ganglia) (9, 14, 19), vagosym- have to be disposed of and destroyed (5). At present, SRMs pathetic trunk (Truncus vagosympathicus) (9), and para- are the , excluding the mandible but including the sympathetic fibers of the (3, 12, 13, 19). brain, eyes, and spinal cord of bovine animals over 12 As a part of the ANS, the ST consists of ganglia that months of age. For bovines over 24 months of age, SRMs are connected by bundles of nerve fibers. In cattle, the ST are the , excluding the vertebrae of the tail, contains 13 thoracic (of which the first and largest ganglion the transverse and spinous processes of the cervical, tho- is fused with the caudal cervical ganglion to the cervico- racic, and lumbar vertebrae, the median sacral crest, and thoracic—the stellate—ganglion), 6 lumbar, 5 sacral and 2, the wings of the sacrum, but including the dorsal root gan- respectively, 3 coccygeal ganglia. The (paired) trunk is lo- glia. SRMs for bovines of all ages include the tonsils, the cated from the most caudal cervical vertebrae, a distance intestines from the to the rectum, and the mes- of 2 or 3 cm from the spine, down to the first coccygeal entery, including the and the pre- vertebrae, embedded in fatty and connective tissue. Ganglia vertebral ganglia. Control and removal of certain tissues as of the ST are not SRMs (8). SRM are now also mandatory in the United States (21). Most transmissible spongiform encephalopathy patho- The agent of bovine spongiform encephalopathy (BSE) genesis studies refer to the scrapie agent in mice, hamsters, is mainly transmitted orally after exposure to feedstuffs car- or sheep. For cattle, only a few and incomplete data on rying abnormal prion proteins (PrPSc). Such PrPSc first ac- tissue contamination with the BSE agent are available from cumulate in gut-associated lymphoid tissues (Peyer’s patch- experimental or field studies (6). Moreover, these data are es) and in the ganglia of the enteric nervous system, which close to the limit of detection, even in tissue from the cen- is the intestinal part of the autonomous nervous system tral nervous system (6). Concerning the ST as part of the (ANS) (1, 2, 11, 19). From here, different possible path- ways toward the central nervous system have been dis- ANS, in cattle samples, no infectivity was found (23, 24). cussed. ANS structures possibly involved (Fig. 1) include Consequently, the involvement of ANS in BSE pathogen- the prevertebral ganglia (ganglion coeliacum, ganglion esis is not completely known, but the anatomy of the ANS mesentericum craniale, and caudale), greater and minor and its close connection to the central nervous system and (Nervus splanchnicus major and Nervi enteric nervous system (Fig. 1) support the conclusion that the ST serves as a potential transfer route for pathogenic * Author for correspondence. Tel: ϩ49-30-83852791; Fax: ϩ49-30- prion proteins on their way to the brain stem after the in- 83852792; E-mail: [email protected]. vasion of a host (9). The time window during this transfer J. Food Prot., Vol. 70, No. 12 CUTTING PLANTS 2907

recent investigation of different cutting methods of bone-in short loins showed only low contamination with nervous system tissue (18). However, to our knowledge, studies on the fate of the ST during commercial cutting never have been published. Irrespective of a potential infectivity as- sociated with ANS structures, this study focused on daily practices in cutting plants of different capacities and the fate of the ST ganglia, which possibly might represent a transfer route for PrPSc.

MATERIALS AND METHODS Plants. A total of 37 bovine cutting plants in Northeast and

Northwest Germany were visited (one visit per plant). Based on Downloaded from http://meridian.allenpress.com/jfp/article-pdf/70/12/2906/1678262/0362-028x-70_12_2906.pdf by guest on 02 October 2021 their capacity per week, they were allocated to three major groups: (i) group I, capacity of 100 to 1,600 tons (12 plants); (ii) group II, a capacity of 10 to less than 100 tons (13 plants); and (iii) group III, capacity from 1 to less than 10 tons (12 plants). Large premises (group I) represent the majority of German beef produc- tion plants.

Observations. To ease the observations, the ST was divided into five portions, which were investigated separately: (i) (T1), (ii) fore (T2 to T6), (iii) hind tho- racic ganglia (T7 to T13), (iv) lumbar ganglia (L1 to L6), and (v) sacral ganglia (S1 to S5). FIGURE 1. The sympathetic nervous system (cross-sectional be- In all plants, eight identical destinations for cut pieces were tween the 6th and 10th thoracic ). Vertebra (1, dorsal identified (Fig. 2): (i) ‘‘meat for processing,’’ all meat used for process; 2, vertebral arch; 3, transverse process), spinal cord (4, meat products; (ii) ‘‘other meat for consumption,’’ cut or deboned white matter; 5, gray matter, dorsal horn; 6, gray matter, lateral meat, including valuable parts such as filet; (iii) ‘‘fat for con- horn; 7, gray matter, ventral horn), 8, paravertebral ganglion sumption,’’ fat for human consumption (including the food in- (sympathetic trunk ganglion); 9, dorsal root ganglion; 10, pre- dustry); (iv) ‘‘fat for other use,’’ fat for the nonfood industry; (v) vertebral ganglion; 11, (a, afferent fiber, cell body ‘‘bones for industry,’’ bones for the nonfood industry; (vi) ‘‘bones (perikaryon); b, afferent fiber, dendrite); 12, afferent sympathetic for consumption,’’ bones for human consumption; (vii) ‘‘bones fiber; 13, spinal nerve; 14a, dorsal branch of the spinal nerve for SRMs,’’ bones disposed of as SRMs; and (viii) ‘‘bones for (efferent fiber); 14b, ventral branch of the spinal nerve (efferent disposal,’’ bones disposed of for rendering. fiber); 15, efferent sympathetic fiber in the ventral rootlet: pre- For the observations, a record sheet was used containing all ganglionic, medullated; 16, sympathetic fiber within the white five portions of the ST and all eight destinations. Every worker communicating branch; 17, sympathetic fiber, Ramus intergan- was observed three times, and each observation was recorded on glionaris; 18, sympathetic synapsis; 19, efferent sympathetic fiber: a single sheet. Before cutting, all carcasses were checked for the preganglionic, medullated; 20, sympathetic fiber, postganglionic, presence of tissues expected to contain the ganglia. If the partic- nonmedullated (a and b, gray communicating rami to the dorsal ular tissue had already been removed, the carcass was not enrolled and ventral branches of the spinal nerve); 21, sympathetic fibers, in the observation. Sometimes, only portions of carcasses were greater splanchnic nerve; 22, efferent sympathetic fiber: postgan- cut. In such cases, the respective data were used. The workers did glionic, nonmedullated. not know why they were being observed. A total of 160 workers were observed, each person over three iterations of their individ- might represent a risk for consumers because of a lack of ual cutting operation. The whole investigation was done by two persons. clinical signs and an inability to detect the agent during this period. Statistical analysis. Contingency tables were used to ex- With respect to contamination with the BSE agent, a amine the relationship between tissue destination and either its

FIGURE 2. Destination of meat cuts dur- ing the observations. 2908 PISKE ET AL. J. Food Prot., Vol. 70, No. 12

TABLE 1. Destination of cuts, decisions made by workers, and TABLE 2. Destination of parts of the sympathetic trunk: human absolute numbers consumption versus nonhuman purposes Capacity group: Destination:

Destination I II III Total Human Nonhuman Sympathetic trunk consumption consumption Total T1 Food T1 N 105 123 228 Meat for processing 24 1 18 43 % within all T1 46.1 53.9 100.0 Other meat for consumption 2 24 0 26 Standard residual 3.5 Ϫ2.5 Fat for consumption 12 3 9 24 T –T N 87 135 222 Bones for consumption 6 0 6 12 2 6 Nonfood % within all T2–T6 39.2 60.8 100.0 Ϫ Fat for other use 48 40 21 109 Standard residual 1.7 1.2

Bones for disposal 2 1 0 3 T7–T13 N 15 186 201 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/70/12/2906/1678262/0362-028x-70_12_2906.pdf by guest on 02 October 2021 Bones for industry 0 0 0 0 % within all T7–T13 7.5 92.5 100.0 Bones for SRM 11 0 0 11 Standard residual Ϫ6.3 4.4

Total 105 69 54 228 L1–L6 N 102 45 147

T2–T6 % within all L1–L6 69.4 30.6 100.0 Food Standard residual 7.8 Ϫ5.4 Meat for processing 14 17 12 43 S1–S5 N 9 165 174 Other meat for consumption 0 20 1 21 % within all S1–S5 5.2 94.8 100.0 Fat for consumption 0 0 9 9 Standard residual Ϫ6.4 4.4 Bones for consumption 6 2 6 14 Nonfood Total N 318 654 972 Fat for other use 36 24 12 72 % within whole Bones for disposal 12 3 0 15 sympathetic trunk 32.7 67.3 100.0 Bones for industry 0 0 0 0 Bones for SRM 37 3 8 48 Total 105 69 48 222 origin (i.e., the five portions of the ST) or the plant capacity (I, T7–T13 II, and III). For that purpose, all observations (pieces) were cat- Food egorized in two groups: workers’ decisions for human consump- Meat for processing 0 0 0 0 tion (i.e., allocation meat for processing, other meat for consump- Other meat for consumption 0 0 0 0 tion, and fat for consumption as well as bones for consumption) Fat for consumption 0 0 0 0 and observations reflecting nonhuman consumption. As the null Bones for consumption 0 6 9 15 hypothesis, it was assumed that the tissue destination was inde- Nonfood Fat for other use 0 1 0 1 pendent of the origin, respectively, of the plant capacity, which ␹2 ␣Ͻ Bones for disposal 12 12 0 24 was calculated as the test ( 0.05). Finally, the standardized Bones for industry 0 0 0 0 residual value served as an indicator of a significant deviation Bones for SRM 84 59 18 161 from the null hypothesis. Following the method of Bu¨hl and Zo¨fel Ͼ Total 96 78 27 201 (4), cells with an absolute value of 2 were regarded as signifi- cantly different from the null hypothesis. L1–L6 Food RESULTS Meat for processing 22 30 12 64 Other meat for consumption 11 9 2 22 Fate of tissues. Based on the observations, 32.7% of Fat for consumption 4 6 6 16 the decisions made by workers placed the tissue in channels Bones for consumption 0 0 0 0 for human consumption. However, when confronted with Nonfood the same tissue, workers decided differently. Considerable Fat for other use 14 18 13 45 Bones for disposal 0 0 0 0 quantities of stellate ganglia, fore thoracic ganglia, and in Bones for industry 0 0 0 0 particular lumbar ganglia went into the food chain (Tables Bones for SRM 0 0 0 0 1 and 2). Total 51 63 33 147 Stellate ganglia (T1) and fore thoracic ganglia (T2 to

S1–S5 T6) most frequently went into the category fat for other use. Food Fore thoracic ganglia (T2 to T6) also went into fat for other Meat for processing 0 0 0 0 use but were also frequently discarded with the bones as Other meat for consumption 0 0 0 0 SRMs. The hind thoracic ganglia (T to T ) primarily re- Fat for consumption 0 0 0 0 7 13 mained connected to the bones and were thus frequently Bones for consumption 0 0 9 9 Nonfood being disposed of as SRMs or for rendering. Lumbar gan- Fat for other use 0 0 0 0 glia (L1 to L6) never went with the bones but were mostly Bones for disposal 34 6 9 49 found on meat for processing or with fat for other use. Bones for industry 0 3 0 3 Sacral ganglia (S1 to S5) most often appeared with SRMs Bones for SRM 53 48 12 113 or bones for rendering. Total 87 57 30 174 Concerning the origin of the tissue, the null hypothesis J. Food Prot., Vol. 70, No. 12 CUTTING PLANTS 2909

TABLE 3. Destination of parts of the sympathetic trunk, depend- ing on the capacity Destination:

Human Nonhuman Capacity group consumption purposes Total

I N 101 343 444 % within capacity group 22.7 77.3 100.0 Standard residual Ϫ3.7 2.6 II N 118 218 336 % within capacity group 35.1 64.9 100.0 Standard residual 0.8 Ϫ0.5

III N 99 93 192 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/70/12/2906/1678262/0362-028x-70_12_2906.pdf by guest on 02 October 2021 % within capacity group 51.6 48.4 100.0 Standard residual 4.6 Ϫ3.2 Total N 318 654 972 % within all plants 32.7 67.3 100.0 was rejected. Tissue from T and L to L sections was 1 1 6 FIGURE 3. Line denoting the sawing distance from the transverse significantly more likely to appear in human food channels, processes (knife indicating the cutting line, file indicating the sym- whereas tissue from T7 to T13 and S1 to S5 was more fre- pathetic trunk, and needles indicating ganglia). quently destined for nonhuman use. Plant categories. Based on plant cutting capacity, op- erators acted differently (P Ͻ 0.05). In group III plants were used for nonfood purposes and disposed of as SRMs (small plants), significantly more material went into the hu- or in other ways (Table 1). The operators performed dif- man food chain, whereas in group I plants (large plants), ferently, which indicates a lack of standard operating pro- more tissue was destined for nonfood use (Table 3). cedures in this area of processing. The stellate ganglion, which is located close to the first DISCUSSION rib within the fatty tissue, has a weight of about 1.25 to Slaughtered cattle (Ͼ30 months of age) are to be man- 4.50 g (17). Hence, because of its size, the respective fat datorily tested for BSE with sample materials from the obex chunk containing the ganglion can easily be removed. The region, which is located in the brain stem. However, be- fore thoracic ganglia are located within fat and connective cause the host might harbor PrPSc that have not yet reached tissue close to the spine, between the long muscle of the the brain via the ST or vagus nerve (neither of which are (M. longus colli) and the vertebral column. Here, the specified as SRMs), a negative test result does not exclude muscle may be cut off at a certain distance from the spine, an early BSE infection. Several earlier reports indicate that leaving the ganglia connected to the bones, or the muscle the ANS plays an important role in the agent’s transfer after including fatty and connective tissue can be disconnected invasion of the host (3, 15, 16, 22). and the ganglia separated later. Fat tissue can be handled Based on initial results from an experimental study more easily in a soft condition before chilling. Hence, fat with cattle, Hoffmann et al. (13) considered two PrPSc removal can be done more conveniently in the abattoir. transfer routes: transfer via the sympathetic splanchnic Here, veterinary control is available continuously. The nerves and the radix ventralis and transfer via the parasym- transverse processes of the thoracic vertebrae are not SRMs pathetic nerve fibers of the vagus nerve (13). The splanch- (8) and are consequently sawn off. In practice, the saw nic nerves interconnect between the spinal cord and pre- might come too close to the spine, and hind thoracic ganglia vertebral ganglia, their fibers leading through the paraver- might rest on the processes. Therefore, a distance of 5 cm tebral ganglia (i.e., the ST ganglia) partly without function- from the spine is recommended (Fig. 3) to keep these gan- al interconnection. To our knowledge, the extent of such a glia on the bones for the removal and final destruction of relay function is not known in cattle. Consequently, the ST possible present PrPSc. Although the lumbar ganglia located ganglia remain a potential transfer route for pathogenic pri- on the filet chain may be difficult to detect or remove dur- on proteins. Such a presumably small but remaining risk ing normal operation, the transfer route is mainly via the can be balanced by keeping the respective tissue out of the greater splanchnic nerve to the . Finally, the food chain (9). Ganglia in particular are assemblies of nerve sacral ganglia, which are located on the surface of the sacral cell bodies, and because of their size, they might pose a bone and not in contact with the musculature, go with the higher risk than pure nerve fibers. sacral bone as SRMs. During the commercial cutting of bovines, sympathetic Workers acted differently depending on plant capacity, nervous tissue enters the food chain. Based on our obser- which was also true for individual workers during any one vations, about one-third of the ST went into the category period of observations. For preventive measures, standard human consumption (Table 2). The remaining materials operating procedures should be developed for handling 2910 PISKE ET AL. J. Food Prot., Vol. 70, No. 12

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