Journal of Applied Bacteriology 1981, 50, 239-245 6671 102/19

Spreading of Salmonellas during Cattle Slaughtering

A. STOLLE

Department of Meat Hygiene, Free University of Berlin, Brummerstrasse 10, 1000 Berlin 33, West Germany

Received 11 October 1979 and accepted 28 July 1980

The spread of salmonellas during the slaughtering of cattle in the Berlin (West) slaughterhouse was investigated. The slaughterline was divided into 12 areas. During the first examination, which lasted eight months, the equipment and implements a t each stage of slaughter, and faeces of cattle were tested. Salmonellas were not isolated from any of the 226 samples of faeces whereas 14 isolations (1.8%) were made from the 768 swabs taken from equipment. Most isolates were obtained within the step of opening the abdominal cavity.

In a second survey 61 (4.3%) of 1392 swab samples and 2 (0.75%) of 267 faeces samples were positive. Of the different processing steps, cutting off the hooves and loosening the skin of legs gave the highest recovery of salmonellas. Moderate recoveries were obtained after opening the abdominal cavity. Removal of head, loosening the skin of head, removing the hide and splitting the breastbone and the carcass did not result in the isolation of the organism. Salmonella anaturn was the most common isolate. The same serotypes were isolated from both carcasses and equipment.

EPIDEMIOLOGICAL DATA from many countries indicate that salmonella infections of livestock are still widespread. Indeed some papers indicate an increasing amount of contamination in some countries, e.g. England and Wales (Sojka et al. 1977; Wray & Sojka 1977), Sweden (Gunnarson et al. 1974), The Netherlands (Guide & Valkenburg 1975) and Germany (Pietzsch 1978).

The association between salmonellosis in man and the infection of foodstuffs by animal sources has been clearly established (Watson 1975). Contamination of red meat by salmonellas occurs at the abattoirs as there is no effective means of detecting symptomless excretors. Meat may well be contaminated from such animals and salmonellas can gain access to the meat at any stage in butchering (Norval 1961). Their occurrence in equipment and in faeces samples has been reported (Edel et al. 1969; Childers et al. 1973; Stolle & Reuter 1978). Material taken from hooves, hide and hair of slaughtered animals has been shown to be contaminated (Norval 1961; Patterson & Gibbs 1978). Isolations have also been made from tools, floors and especially from the butchers’ knives and utensils (Lehmann 1964; Shomrony et al. 1965; Watson 1975). Although there is little information on the incidence of salmonellas on beef carcasses, it is sufficient to show that a risk exists. Thus a wide range of incidence of contamination of beef carcasses has been reported-O.2% (Felsenfeld et al. 1950) and 0.5% (Goo el al. 1973) to 4.3% (Nazer & Osborne 1976) up to the highest mark with 74% salmonella positive samples (Weissmann & Carpenter 1969). This paper presents information on the incidence of contamination in the slaughterhouse of Berlin (West) in which cattle from the German Democratic Republic, Poland, Bavaria and the northern part of the Federal Republic of Germany were slaughtered. 0021-8847/81/020239+07$01 .OO/O (2391 0 1981 The Society for Applied Bacteriology

240 A. STOLLE

Materials and Methods

The investigation was done in a modern cattle slaughterhouse equipped with a semi-automatic system. All samples were collected from 0600 to 0800 h during the routine slaughtering process.

TABLE 1

Dicision of the slaughterline into 12 steps

H I K L M

Stabbing, removal of head Removal of front hooves, loosening of skin from chest Removal of rear hooyes. loosening of skin from hind legs Splitting of pelvic bones. removal of genitals Hooks of hide pulling machine Splitting breast bone Opening abdominal cavity Splitting of carcass Uncovering kidneys, removal of spare fat Removal of skin of head Veterinary meat inspection (incisions for C).sricercu.r inermis. incisions at Lnn. jejunulc.~) Ilnhooking carcass from slaughter production line

TABLE 2

Tested combinations of steps of the slaughterline, number of test days and samplesjstep

Combinations and numbers of samples, steps Test days Total samples;

(n) A B C D E F G H I K L M combination

3 3 3 2 2 2 2 2 4 4 4 4 4 4 5 5 4 4 4

Total 65

40 20 18 78 38 30 28 96 38 30 16 84

20 20 22 62 18 20 16 54 18 20 30 68 20 18 16 54 20 22 28 70

20 20 20 60 18 18 30 66

24 28 40 92 24 20 20 64 24 40 16 80

28 18 20 66 30 18 16 64

36 20 18 74 40 40 28 108

20 36 20 76 28 18 30 76

1 1 6 c 2116 1392

SPREADING OF SALMONELLAS 241

Sampling programme

Two separate surveys were done: the first (series A) was from August 1977 to March 1978, the second (series B) was from March 1978 to November 1978. In series A the slaughterline was divided into 12 stages (Table 1) and tools and equipment of the slaughterers at each designated stage were swabbed on separate days in random order. In series B three different stages were combined and investigated in 1 d (Table 2). Two swabs were rubbed on the tools and equipment and a further two swabs were used to

Fig. 1. Carcass site, view from the inside. 8, Areas of swabbing.

swab the carcass as shown in Fig. 1. Sampling was done as follows: stage A was tested in three different combinations (ABC, AEM and AKL) and each of these combina- tions was tested three times. Faecal samples were taken from the rectum of cattle immediately before slaughter.

Treatment of samples

Swabs were put into two test tubes each containing 5 ml of peptone water and transported to the laboratory within 2-4 h. They were shaken by hand and incubated

342 A. STOLLE

for 24 h at 37 C. The contents of one tube were then added to the 50 ml of Tetrathionate Enrichment Broth (Oxoid) and the contents of the other to 50 ml of Cystine Selenite Enrichment Broth (Merck) which had been held at 45'C for 15 min before use. After 24 and 48 h at 43 C these were subcultured on Brilliant Green Agar (Oxoid) and on Litmus-Lactose-Crystal Violet Agar (Merck). Each suspect isolate was tested serologically and identified biochemically and identifications were confirmed by the Bundesgesundheitsamt Berlin (West).

Results

The 226 faecal samples of series A were all negative for salmonellas whereas two (0.75",) of the 267 faeces samples belonging to series B yielded isolates of Salmonella

TABLE 3

Incidence of salmonellas on slaughterhouse equipment as shown by .swab sampling at random during an eighr month period (series A )

No. positive Salmonella No. swabs

Processing swabs Iyphimurium stages taken n (",,) unaticrn dublrn heidelberg var. copenhagen

A 64 B 73 c 54 D 61 E 75 F 76 G 51 H 54 I 62

K 66 L 63 M 69

Total 768

2 (2.7) I(1.8)

I(1.3)

5 (9.8) l(1.8)

I (1.5) 3 (4.3)

14i1.8)

1

4 I

I I 1 I

9(1.1) 3 i O . 3 ) l(O.1)

1

l(O.1)

Max. value in bold.

anafum. These isolations were not made on days when positive results were obtained on the slaughterline. Of the 768 swabs taken from the tools of abattoir workersin series A, 14 (1.89:) were found to be positive for salmonellas (Table 3). Four serotypes (anatum. heidelberg, dublin and typhimurium var. copenhagen) were identified. Isolations were made from seven of the 12 stages in the slaughter and butchering process (Table 3).

In series B salmonella serotypes anatum (78.6"), london (16.4%) and dubiin (5%) were isolated from 61 (4.37") of the I392 swabs taken from tools and from the carcass areas touched by these tools (Table 4).

The evaluation of the results in terms of the frequency of isolation is shown in Fig. 2. This shows that there were certain steps in the slaughterline where there was a high incidence of salmonellas: cutting off the hooves and loosening the skin from the legs,

SPREADING OF SALMONELLAS 243

TABLE 4

Incidence of salmonellas on slaughterhouse equipment and carcass sites as shown by swab sampling each of three stages combined

during a day (series B)

No. Salmonella positive

No. swabs analum london dublin Processing swabs

stage taken n (%) E C E C E C

A 116 B 116 16 (13.8) C 116 22 (18.9) D 116 3 (2.9) E 1 I6 F 1 I6 G 116 6 (5.2) H 1 I6 I 116 5 (4.3) K 1 I6 L 116 5 (4.3) M 116 4 (3.5)

Total 1392 61 (4.3)

8 1 1 11 10 1

1 1 1

2 2 1 1

2 2 1

1 1 2 1 1 1 1 1

25 23 5 5 2 1

E, equipment; C, carcass sites (see Fig. I ) ; max. values in bold

A m i I K L M

Stages

Fig. 2. Incidence of salmonellas in the cattle slaughterline (n = 2160). See Table 1 for explanation of stages.

234 A. STOLLE

followed by opening the abdominal cavity. veterinary meat inspection and dressing the carcasses.

Discussion

Our results with the faecal samples are in accord with those of Childers et al. (1973), Schulz et al. (1975), and Stolle & Reuter (1978). In general, a single faecal sample of animals is apparently not adequate to identify latent salmonella carriers. The results obtained from examination of tools and equipment, however, demonstrate clearly that the incidence of salmonellas on the slaughterline originated from the animals. Similar results were achieved by Lehmann (l964), Guinee & Valkenburg (1979, Edel et ai. (1977) and Stolle & Reuter (1978). I t was concluded that mud on the hooves and the skin are the most important sources of salmonellas. The importance of these sources was noted by Norval(l961) and Patterson & Gibbs (1978).

Contamination of the abdominal and pelvic cavities with salmonellas was noted by Childers et at. ( 1 969). The isolation of the same salmonella strains from hands, clothes, tools and the carcasses at the same stage indicate that the transmission might have been from animal to man or may have been from hide to tool and to the abdominal cavity. I t shows that the organism can pass from animal to man as already pointed out by Norval (1961). Shomrony ef al. (1965), Watson (1975) and Peel & Simmons (1978). The incidence of surface contamination agrees with those of other workers (Felsenfeld et al. 1950; Weissman & Carpenter 1969; Goo et al. 1973; Nazer & Osborne 1976).

The author wishes to thank Prof. Dr G. Reuter, Head of Meat Hygiene at the Free University of Berlin for his helpful advice and criticism in preparing this paper, Mrs. S. Kringel for her valuable technical assistance and Prof. Dr. 0. Pietzsch, Institut fur Veterinarmedizin, Bundesgesundheitsamt Berlin, for confirming the identity of the salmonella strains. This paper was read at the XXIst World Veterinary Congress in Moscow. 1979.

References

CHILDERS, A. B.. KEAHEY, E. E. & VISCEXT, P. G. 1973 Source of Salmonella contamination of meat following approved livestock slaughtering procedures. Journal of Milk and Food Technologj. 36, 635- 638.

EDEL, W., GUINEE, P. A . M. & KAMPELMACHER. E. H. 1969 Samonella infection in fattening calves after slaughter. Zenfralblutt fur Vererin&rnedizin 17, 479-484.

EDEL, W., VAN SCHOTHORST, M.. VAN LEUSDEN, F.M. & KAMPELMACHER. E. H. 1977 The incidence of Salmonellae in man. insects. gulls as well as foods, scrapings from butchers’ blocks. effluents of sewage treatment plants and drains from butchers’ shops. Ttjdschrlft roor Diergeneeskunde 102, 365-376.

F~LSENFELD, 0.. YOUNG. V.M. & YOSHIMURA. T. 1950 A survey of Salmonella organisms in market meat, eggs and milk. Journal oj’the American Veterinary Medical Association 116,

Goo, V. Y . L., CHING. 0. L. & GOOC-H. J . M. 1973 Comparison of Brilliant-green-agar and Hectoen-enteritic-agar media in the isolation of Salmonella from food products. Applied Microbiology 26, 288-292.

GUINEE, P. A. M. & VALKENBURG, J . 1975 Salmonella Isolierungen in den Niederlanden 1966-13. Zentralblatt Bakteriologie I , Originale A 231, 97-107.

GUSNARSON. A.. HURVELL, B., NORDBLOM, B., RUTQUIST, L. & THAL, E. 1974 Salmonella

17-31.

SPREADING OF SALMONELLAS 245

isolated from animals and feedstuffs in Sweden over the period 1968-72. Nordisk Veterinaermedicin 26, 499-5 17.

LEHMANN, W. 1964 Vorkommen und Lokalisation von Salmonellen in fleischverarbeitenden Betrieben. Monatshefte fur Veterinarmedizin 19, 744.

NAZER, A. H. K. & OSBORNE, A. D. 1976 Salmonella infection and contamination of veal calves: a slaughterhouse survey. British Veterinary Journal 132, 192-201.

NORVAL, J . 1961 Hygiene in slaughterhouses. Veterinary Record 73, 78 1-784. PATTERSON, J. T. & GIBBS, P. A. 1978 Sources and properties of some organisms isolated in two

abattoirs. Meat Science 2, 263-273. PEEL, B. & SIMMONS, G. C. 1978 Factors in the spread of Salmonellas in meatworks with special

reference to contamination of knives. Australian Veterinary Journal 54, 106-1 10. PIETZSCH, 0. 1978 Verbreitung der Salmonella-Infektionen bei Tieren, tierischen Lebens- und

Futtermitteln in der Bundesrepublik Deutschland einschl. Berlin (West) Bundesgesund- heitsblatt 21, 38941 1.

SCHULTZ, W., KIUPEL, H. & GUNTHER, H. 1975 Die Salmonellose des Rindes-Vorkommen, wirtschaftliche Bedeutung, Epizootiologie. Monatshefte f ur Veterinarmedizin 30,53&534.

SHOMRONY, A,, IMRE, Z. & ILAN, J. 1965 Salmonellosis in some of the slaughterhouses in Israel. 4th Symposium of the World Association of Veterinary and Food Hygiene, Lincoln, Nebraska, U.S.A.

SOJKA, W. J. , WRAY, C., SHREEVE, J. & BENSON, A. 1977 Incidence of Salmonella infection in animals in England and Wales, 1968-74. Journal of Hygiene, Cambridge 78,43-56.

STOLLE, A. & REUTER, G. 1978 Die Nachweisbarkeit von Salmonellen bei klinisch gesunden Schlachtrindern im Bestand, nach dem Transport zum Schlachthof und wahrend des Schlachtprozesses. Berliner und Miinchener Tierarztliche Wochensehr$t 91, 188-1 93.

WATSON, W. A. 1975 Salmonellosis and meat hygiene: red meat. Veterinary Record96,374-376. WEISSMANN, V. A. &CARPENTER, J. A. 1969 Incidence of Salmonella in meat and meat products.

WRAY, C. & SOJKA, W. J . 1977 Reviews of the progress of dairy science: bovine Salmonellosis. Applied Microbiology 17, 899-902.

Journal of Dairy Research 44, 383-425.

Erratum

A Note on Bile Acids Transformations by Strains of Bifidobacterium

ANNAMARIA FERRARI, NOVELLA PAClNl AND ENRICA CANZI

Journal of Applied Bacteriology 1980, 49, 193-197

Table 1 on page 195 should read:

TABLE 1

Production from cholic acid of monocheto-derivatives by 28 strains of Bifidobacterium spp.

3 - 0 X O I - or 12-OX0

Bifidobacterium adolescen tis

angulatum

animalis

bijidum hreve

catendatum

denrium

longum

suis

'subtile' Group

Unassigned Homology Group I

Unnamed

ATCC 15703 F20 F147 ATCC 27669 ATCC 27610 ATCC 21611 ATCC 21612 ATCC 21673 ATCC 27614 ATCC 15696 ATCC 1510 1 B628 B648 ATCC 27539 ATCC 21615 ATCC 21616 B1331 ATCC 27534 ATCC 27678 B654 F66 F130 ATCC 21533 ATCC 27683 ATCC 21684 RA161

ATCC 279 1 I ATCC 279 18

+ , Production; -, non-production.

Erratum

The Detect ion and Differentiation of Fi bri nolyt ic Enzymes in Bacteria

L. JEFFRIES AND D. E. BUCKLEY

Journal of Applied Bacteriology 1980, 49, 479492

Table 9 on page 489 should read:

TABLE 9

The distribution ofjibrinolytic enzymes in cultures of Bacteroides melaninogenicus

Inhibition of fibrinogen01 ysis

by

Strain Fraction TLCK* EDTAT

Bacteroides melaninogenicus subsp. Whole culture + $ + k asaccharolyticus Sedimented cells - +

Supernatant (cell-free) + -

Bacteroides melaninogenicus subsp. Whole culture + k

Supernatant (cell-free) + f

Sonicated cells -

+ +

in termedius Sedimented cells -

Sonicated cells -

* Tosyl-L-lysine-chloromethyl ketone. t Ethylenediaminetetraacetic acid. $ +, Zone of fibrinogenolysis reduced by > 20%; f , zone of fibrinogenolysis reduced by 1@20%; -, zone of fibrinogenolysis reduced by < 10%.

Erratum

Lactose lactis

Hydrolysing Enzymes in Streptococcus and Streptococcus cremoris and also

in some other Species of Streptococci

J. A. E. FARROW

Journul of Applied Bucteriology 1980, 49,493-503

Table 6 on page 499 should read:

TABLE 6

Lactose hydrolysing enzymes of whole cells and cell-free extracts of Streptococcus lactis, Streptococcus faecalis and Streptococcus faecium

* Units* of

dry cells mg protein Units* of enzyme x 103/mg enzyme x lo3/

Toluene-acetone Sodium deoxycholate Cell-free extracts NCDO

Species number &gal P-Pgal P-gal B-Pgal b-gal D-Pgal

Streptococcus lactis 712 3 28 5 31 0 370

2054 264 16 342 19 340 48 209 1 101 12 191 19 88 54

faecalis 58 I I I 3 1 12 40 0 249 610 10 39 13 21 1 189

fuecium 942 537 32 256 23 437 94 1980 9 12 13 1 1 80 476

* One unit of enzyme activity releases 1 pmolONP/min.