Composite A 2 was similar to Aj but different in that: (1) two-tenths ml of MT broth culture was used in place 

 of 1 ml and; (2) single-strength TT broth was used in place of double strength TT broth. 



The number-2 aliquot of each of the 10 samples in the lot was cultured according to a standard procedure (1). 

 Composite B was prepared from TT broth cultures used in the standard procedure. A 0.1 ml amount from each of 

 the 10 cultures was transferred to a tube containing 10 ml of single strength TT broth. After overnight incubation, 

 the composite culture was examined as described above. 



Results and Discussion 



Bacteriologic examinations were performed on 600 animal byproduct samples. The results of these 

 examinations are presented (table 1). Of the lots examined, 41 contained samples in which salmonellae were isolated 

 from one or more by standard methods. Forty-three lots were positive by composite method A i5 44 lots were 

 positive by composite method A 2 and 41 lots were positive by composite method B. Three composites were negative 

 by the three compositing techniques that contained 1 or more 30 g aliquots that were positive by standard methods. 



Table 1. -Comparison of standard culture and wet compositing procedures for the detection of Salmonellae in 



animal by-products 



Lot no. 



Standard culture 



Wet composites 



A,l 



A, 2 



Lot no. 



Standard culture 



Wet composites 



A,l 



A, 2 



1 . 



2 . 



3 . 

 1 . 



5 . 



6 . 



7 . 



8 . 



9 . 

 10. 

 11. 

 12. 

 1 3. 

 14. 

 15. 

 10. 

 17. 



ia. 

 I 'J. 



20. 

 21. 

 22. 

 23. 



21. 

 25. 

 26. 



27. 

 21',. 

 29. 

 Mil. 



5/10# 



1/10 



0/10 



4/10 



3/10 



1/10 



0/10 



1/10 



1/10 



5/10 



0/10 



0/10 



0/10 



3/10 



0/10 



0/10 



7/10 



8/10 



0/10 



1/10 



0/10 



0/10 



4/10 



7/10 



9/10 



5/10 



8/10 



8/10 



5/10 



9/10 



+ 



31 



+ 



32 



- 



33 



+ 



34 



+ 



35 



+ 



36 



- 



37 



+ 



38 



+ 



39 



+ 



40 



- 



41 



- 



42 



- 



43 



+ 



44 



+ 



45 



- 



46 



+ 



47 



+ 



48 



+ 



49 



+ 



50 



- 



51 



- 



52 



+ 



53 



+ 



54 



+ 



55 



+ 



56 



+ 



57 



+ 



58 



+ 



59 



+ 



60 



3 



10 



10 



ill 







III 







III 







III 



1 



III 



6 



ill 



5 



III 







10 



6 



111 



9 



10 



9 



10 







10 



L0 



111 



8 



10 







10 



1 



10 



6 



10 



0/ 



111 



2 



111 



5 



10 



1 



10 



1 



10 



1 



III 



2 



10 



LI 



10 



2 



10 







III 



3 



III 



1 



III 



+ 



+ 



+ 



+ 



+ 



- 



+ 



- 



+ 



+ 



+ 



A- 



+ 



+ 



- 



+ 



+ 



- 



+ 



+ 



+ 



+ 



+ 



- 



+ 



- 



+ 



+ 



+ 



+ 



= Pre-enrichment broth cultures subcultured in double strength tetrathionate broth. 



= Pre-enrichment broth cultures subcultured in single strength tetrathionate broth. 



= No pre-enrichment. 

 #= No. 30 g samples positive/No. 30 g samples examined. 

 + = Salmonella isolation. 

 - = No Salmonella isolation. 



38 



