Recovery of Salmonella from Water, Equipment, and Carcasses in Turkey Processing Plants

QMOO Applied PoulUy Science, Inc

RECOVERY OF SALMONELLA FROM WATER, EQUIPMENT, AND CARCASSES IN

TURKEY PROCESSING PLANTS

DARRELLw TRAMPEL' Department of VeterinaryDiagnostic and Production Animal Medicine, 2270 College of VeterinaryMedicine, Iowa State University,Ames, LA 50011 Phone: (515) 2940710

FAX: (515) 2948793

Primary Audience: Veterinarians, Plant Managers, Quality Assurance Personnel, Flock Supervisors, Researchers

1 To whom correspondence should be addressed

Downloaded from http://japr.oxfordjournals.org/ at Wayne State University on April 7, 2015

E-mail: xltrampe@met~iastate.edu ROBERT J. HASIAK Department ofAnimal Science, College of Agriculture, Iowa State University,Ames, LA 50011 LORRAINE J. HOFFMAN Department of VeterinaryDiagnostic and Production Animal Medicine, College of VeterinaryMedicine, Iowa State University,Ames, LA 50011 MARY C. DEBEY Department of Diagnostic Medicine and Pathobiology, College of VeterinaryMedicine, Kansas State University, Manhattan, KS 66506

SALMONELLA IN TURKEY PLANTS

30

of each flock at one of two slaughter facilities. DESCRIPTION OF PROBLEM Processing procedures, such as scalding, picking, and cooling, were similar in the two plants. Cloacal swabs were collected from 20 (Flocks 1and 2) or 30 (Flocks 3 through 12) live birds from each flock immediately before slaughter while the birds were hanging on shackles. When the stunned birds passed through the scald water, a sample designated "scaldwater'' was collected.After evisceration, a sample of the water in which the carcasses were cooling was designated "pre-chillwater." Carcasses passed into another cooling bath designated as "chill water." The final water in which carcasses were chilled before proceeding to the packing line was designated "post-chill water." Water in which giblets were cooling was designated "giblet water." Metal and rubber components of the feather picker, metal tables, belts, shackles, and metal hock cutters were sampled with cotton-tipped swabs and cultured for Salmonella to further monitor contamination of carcasses during processing. Thirty carcasses from tom turkeys (Flocks 3 through 12) were removed from post-chill water and sampled according to the procedure described by Cox et al. [6]. Briefly, each turkey carcass was placed in a polyethylene bag with 500 mL sterile water, and shaken vigorously for 1min in a mechanically rotated drum. Fluid that drained from the carcass and into the bag was cultured for Salmonella spp. When Flocks 1 and 2 were processed, 20 carcasses were removed from post-chill water and sampled. Additionally, 20 carcasses were removed from pre-chill water for bacteriological testing. SALMONELLA ISOLATION AND IDENTIFICATION Cloacal swabs and swabs of processing plant components were streaked onto blood agar, MacConkey agar, and approximately 5 mL of selenite-cystine broth, and incubated at 37°C for 24 hr. Water samples and fluid obtained from carcasses were mixed with the appropriate volume (approximately 50 mL) of 1Ox selenite-cystine broth, and incubated at 37°C for 24 hr [7l. Cultures identified as Salmonella spp. were serotyped by the National Veterinary Services Laboratories (Ames, IA). If a Salmonella culture crossreacted with more than one serotyping sera,

MATERIALSAND METHODS SAMPLING O F PLANT FACILITIES AND TURKEYS Turkeys from 12Iowa flockswere cultured for Salmonella spp. during routine processing

Downloaded from http://japr.oxfordjournals.org/ at Wayne State University on April 7, 2015

Safety of foods of animal origin has become a high-profile issue of concern to the public and to health professionals [l]. According to a recent report, bacteria were implicated in 87% of cases and 90% of deaths due to foodborne disease [2]. Turkey products ranked third behind dairy products and beef as a known vehicle in foodborne disease cases from 1973-1987 [2]. Between 1973-1975 and 1985-1987, there was a 75% increase in the proportion of foodborne disease outbreaks attributed to Salmonella spp. [2]. During the period from 1973-1987,8% of foodborne outbreaks were associated with consumption of turkey, and Salmonella spp. accounted for 45.6% of human bacterial infections associated with turkey meat. Contaminated processing plant equipment was believed to be a contributing factor in 45% of instances of foodborne disease associated with turkey meat; food from an unsafe source was a risk factor in 14% of the outbreaks [2]. Approximately 70% of Salmonella outbreaks in humans and animals are attributed to only about a dozen serotypes [3]. Cold temperatures may affect the survival of some serotypes of Salmonella [4]. Serotypes more pathogenic in humans are probably more frequently reported by medical authorities because sicker people seek medical assistance [SI. These factors may significantly influence the serotypes of Salmonella most commonly associated with foodborne salmonellosis after consumption of chicken and turkey products. In the studyreported here, we determined the incidenceand serotypesofSalmonellaspp. from cloacal feces of turkeys from 12 flocks immediately before processing. Various components of the processing Line were cultured to identify steps in the processing cycle where contamination of turkey carcasses occurred. Finally, the incidence and serotypes of Salmonella spp. recovered from chilled carcasseswere determined.

Research Report TRAMPEL et al. the culture was reported as "multiple serotypes'' by the laboratory.

31

presence of a greater number of positive samples from Plant 1 than from Plant 2 may be due to a number of factors. Facilities and sanitation were not considered a likely factor, as the plants were similar. Although some defeathering methods can increase the numbers of Salmonella adhering to carcass skin by producing rough surfaces [8], both plants in this study used conventional defeathering processes. Most likely, the differences observed in recovery of Salmonella from chilled carcasses was due to contamination of the exterior of the buds. Salmonella-contaminated or infected live turkeys delivered to a slaughter facility are the primary source of processing plant contamination [9]. 'hrkeys grown in a Salmonella-free environment yield fewer Salmonella-positive birds after evisceration in a processing plant [lo]. Salmonella was recovered from scald, pre-chill, and chill water in Plant 1only, indicatingthat the birds entering Plant 1 were more heady contaminated with Salmonella than those processed at Plant 2. Feather contamination with excrement from the litter is possible. Fecal shedding of Salmonella any time during the growing period could contaminate the litter surface on which the turkeys move and rest, leading to heavy contamination of feet and feathers over time. Furthermore, contact of feathers with dirty crates [ l l ] or Salmonella-laden droppings from live birds during transport could lead to contamination of the exterior of birds enteringthe plant. Rigbyetal. [a] determined that occurrence ofSalmonellaon feather pickers corresponded to increased contamination of carcassesat the end of the processingcycle. Only 1 of 340 cloacal swabs was positive, and that isolation occurred from a turkey processed at Plant 1. However, the flocks with the highest Salmonella recovery rates from carcassesin Plant 1 yielded no positive cloacal swabs. This result is not surprising because shedding of Salmonella in feces is intermittent, and failure to isolate the organism from cloacal swabs does not prove absence of infections in flocks [2]. However, the possibility that random cloacal cultures did not detect the carrier turkeys responsiblefor subsequent fecal contamination of carcasses cannot be excluded. Of interest was isolation of Salmonella from scald water. Bacteria in scald water or on

RESULTS AND DISCUSSION

Downloaded from http://japr.oxfordjournals.org/ at Wayne State University on April 7, 2015

Salmonellawas recovered from carcasses removed from post-chill water in both plants surveyed. Locations within the plant and numbers of samples positive for Salmonella are detailed in Table 1. Salmonella was recovered from equipment and giblet water in at least one samplulg from each plant. Interestingly, recovery of Salmonella from equipment surfaces was accompanied by recovery of Salmonella from giblet water. The possible role of b i o f h of bacteria on equipment surfaces during those processing periods is unknown. In Plant 2 Salmonella sero. reading was recovered from giblet water and from two undesignated equipment surfaces after Flock 11 was processed. However, no Salmonella were recovered from processed turkey carcasses that day. Since there was no evidence of Salmonella sero. reading on carcasses or in waters, the organism may have originatedfrom contaminated crop contents [3], and therefore did not contaminate carcasses. In Plant 1, serotypes of Salmonella isolated from equipment and giblet flume water were present on turkey carcasses. Metal and rubber components of the feather picker were sampled 18 times over the course of the study, and Salmonella sero. sun-diego was recovered from one metal and one rubber component after Flocks 3 and 4 were processed in Plant 1. Salmonella sero. san-diego was isolated from 36 of 43 Salmonella-positive carcasses from Flocks 3 and 4 that day. Salmonella sero. montevideo was recovered from one metal table and three carcasses the same day. On the same day, the giblet water from Flocks 3 and 4, and one turkey carcass from Flock 4 contained Salmonella sero. indiana. Another sample of giblet water from Flocks 3 and 4 contained a multiple serotypes isolate, which was recovered from one carcass in Flock 3 that day. Sources of Salmonella serotypes are detailed in Tables 2 and 3. Plant 1 yielded more Salmonella-positive samples from turkeys, equipment, and water (84/396) than Plant 2 (2/472). Although carcasses in post-chill water were Salmonella positive, no post-chill water samples from either plant were positive for Salmonella. The

7

I

I

i I

!

I I

1 I

I

j

!

!

!

i

!

I

I I

i

1

I

!

I

I

I

I

I

j

I

I

1 I

1

!

I

II

I

I

I

I

d

I

U

! k

Downloaded from http://japr.oxfordjournals.org/ at Wayne State University on April 7, 2015

1

z

v

9

5

!

9: m

I

a

j

SALMONELLA IN TURKEY PLANTS

32

Research Report 33

TRAMPELet al. TABLE 2. Salmonella serotypes recovered from turkey carcasses and water at slaughter plants

Pickers metal

18

1

55

Lsan-dieeo

Pickers rubber

18

1

55

SwMlkgQ

Metal tables

12

0

0

Belts

7

0

0

Hanging shackles

4

0

0

70

3

0

0

Unknown

12

2

16.7

Total

74

4

5.4

carcasses may be protected from heat by fecal particles, feathers, or carcasstemperature, because the carcass doesn’t reach scalding water temperatures. Resuscitation of low numbers of sublethally injured cells may occur after incubation of samples in broth [13]. lbenty carcasses each from Flocks 1and 2, were removed from pre-chill water and sampled by the carcass wash method for Salmonella. Six Salmonella sero. agona, two indiana, and one heidelberg were recovered from nine Flock 1 carcasses. Fourteen prechill carcasses from Flock 2 were positive for Salmonella (elght heidelberg, one infantis, one

SEROTYPE

s. Eding

indiana, one albany, and three multiple serotypes). However, Flock 1yielded only five positive post-chill carcasses, and Flock 2 yielded only one. Incidence of Salmonella apparently decreased on carcassesfrom Hocks 1 and 2 during the time elapsing between prechill and post-chill. James et aZ. [13] reported that the prevalence of Salmonella decreased during evisceration, then increased during immersion chilling. Most Salmonella isolations in the current study came from carcasses removed from post-chill waters, which may support the results of James et al. [14].

Downloaded from http://japr.oxfordjournals.org/ at Wayne State University on April 7, 2015

NO. TIMES P o s m

Hock cutter metal

NO. TIMES

posm

CULTURED

EQUIPMENT

JmR SALMONELLA IN TURKEY PLANTS

34

CONCLUSIONS AND APPLICATIONS 1.Salmonella organisms of a variety of serotypes survive on processed turkey carcasses. 2, Fecal shedding of Salmonella immediately before processing is not consistently associated with recovery of Salmonella from carcass w a s h g s at the end of the processing cycle. 3. Salmonella contamination of carcasses may have originated from "old' feces on the feet and feathers of buds entering the processing plant. 4. Decreasing the numbers of Salmonella on processed carcasses may require removing litter and feces from feathers before birds enter the processing line.

REFERENCES AND NOTES 2. Bean, N.H. and P.M. GrUfin, 1990. Foodborne diseaseoutbreaksin the Unitedstates, 1973-1977: Pathogens,vehicles,and trends. J. Food. Prot.53804-817. 3. Nagarda, K.V., B.S. Pomeroy, and J.E Williams, 1991. Paratyphoid infections. Pages 99-130 in: Diseases of Poult 9th Edition. B.W. Calnek, HJ. Barnes, C.W. Beard, 3 M . Reid, and H.W. Yoder, Jr., eds. Iowa State University Press, Ames, IA. 4. Arroyo, G. and J.A Arroyo, 1995. Detection of -sera s in edible organ meats from markets in Madnd, Spainvwd Microbiol. 12:13-20.

5. Hird, D.W., H. Kinde, J.T. C w , B.R Charlton, RP. Chin,and RL Walker, 1993. Serotypes of isolated from California turkey flocks and their environment in 1984-89 and comparison with human isolates. Avian Dis. 37715-719. 6. Cox, N.k, J.E Thomsoa, and J.S. Bailey, 1983. Procedure for isolation and identification of Salmonella from poult carcasses. Pages 1-10 in: culture Handbook No. %3. Agricultural Research%rvice, USDA. Natl. Tech. Information Service, 5285 Port Royal Road, Springfield, VA 22161. 7. Three loopfulsof the selenite-cystine broth culture were quadrant streaked onto plates of brilliant green sulfa agar, bismuth sulfite agar, and Hektoen enterica ar E i f c o Laboratories, Inc., Detroit, MI 48232). d e r hr incubation at 37"C, one colony from each plate typical of W m .were inoculated onto slants of tnple sugar iron agar and lysine iron agar. Biochemical screeningwas yerformed using glucose, lactose, sucrose, mannitol, ma to%, and dulcitol. Cultures exhibiting after 24 hr at 37°C were confirmed as by mixing with group antisera. Complete serotyping was conducted at the National Vetennary Services Laboratories in Ames, IA.

8. Clouser, C.S., S.J. Knabel, M.G. Mast, and S. Doores, 1995. Effect of type of defeathering system on cross-contamination during commercial processing. Poultry Sci. 74732-741. 9. McCapes, RH., B.I. Osburn, and H. Riemann, 1991. Safety of foods of animal origin: Model for elimination of Salmonella contamination of turkey meat. J. h e r . Vet. Med. Assn. 199:875480. 10. Campbell, D.F., RW. Johnston, M.W. Wheeler, EV. Naga~nga,C.D. Szplansaki, and B.S. Pomeroy, 1984. Effects of the evisceration and cooling processeson the incidence of Salmonella in fresh dressed turkeys grown under --controlled and uncontrolled environments. Poultry sci. 63:1069-1072. 11. Rigby, C.E and J . R Pettil, 1980. Changes in t h e m status of broiler chickens subjected to simulated shipping conditions. Canadian. J. Comp. Med. 44374381.

12. Rigby, C.E,J.R Pettil, M.F. Baker, AH. Bentley, M.O. Salomons, and H. nor, 1980. Sources of salmonellae in an uninfected commercial1 -processed broiler flock. Canadian J. Comp. Med. 44:26?-274. 13. Whittemore, AD., 1993. Research note: A modified most probable number techni ue to enumerate total aerobes, enterobacteriaceae,and on oultry carcass after the whole carcass rinse procedure. !oultxy Sci. Tk2353-2357.

&

14. Jam- W.O., W.O. Williams, Jr., J.C. Pracha, R Johnston, and W. Christensen, 1992. Profile of selected bacterial counts and Salmonella revalence on raw r l t r y in a poult slau ter estatlishment. J. Amer. et. Med. Assn. 2$57-5!?

Downloaded from http://japr.oxfordjournals.org/ at Wayne State University on April 7, 2015

1. Morris, J.G., 1996. Current trends in human diseasesassociatedwith foods of animal origin. J. h e r . Vet. Med. Assn. 209:2045-2047.