|Simmons, Ibn Abdul|
Submitted to: Journal of Microbiological Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2008
Publication Date: 6/17/2008
Citation: Simmons, I.M., Hiett, K.L., Stern, N.J., Frank, J. 2008. Comparison of Poultry Exudate and Carcass Rinse Sampling Methods for the Recovery of Campylobacter spp. Subtypes Demonstrates Unique Subtypes Recovered from Exudate. Journal of Microbiological Methods. 74:89-93. Interpretive Summary: Campylobacters are bacteria that normally inhabit chickens in their gastrointestinal tract and can cause a significant proportion of food-borne disease. The high colonization incidences of poultry by campylobacters and the resultant clinical infections in humans have prompted a number of investigations focused upon identifying and subsequently eliminating Campylobacter spp. from poultry. The most common method of sampling poultry for Campylobacter spp. is the whole carcass rinse method. This method involves placing the whole carcass in a bag, adding sterile buffer, shaking vigorously for 1 min, and then analyzing the resulting rinse. An alternative to this method would be to hold the carcasses for a period of time and sample the fluid that drips off of them, or the exudate. It is unknown if these two methods would recover the same Campylobacter spp. subtypes. Because different Campyobacter subtypes may vary in their ability to survive on food and cause illness, it would be beneficial to know if the two sampling methods recover the same subtypes. During this investigation the number of subtypes recovered between the two methods was similar, however there were some subtypes unique to the exudate samples. Further studies are needed to characterizes these subtypes and determine if they are capable of surviving longer and thus a greater threat to consumers.
Technical Abstract: The carcass rinse procedure is a method commonly used for the detection of Campylobacter spp. on processed poultry products. Alternatively, carcass exudate (weep or drip), a viscous fluid comprised of blood and water that leaks into packaging, can also be sampled. It is unknown however if these methodsdirect carcass rinse or exudate/weep can be utilized to preferentially recover different Campylobacter spp. subtypes. If there is a difference in subtypes recovered, the Campylobacter spp. subtypes from carcass rinse analysis may not be indicative of consumer exposure, as the exudate is the fluid to which consumers are potentially exposed to dues to kitchen cross-contamination. Experiments were conducted to determine if there are differences in recovery of Campylobacter spp. subtypes between the two methodologies. The experiment was performed in triplicate using three flocks located on different farms. For each flock 50 fecal samples were obtained on the farm, 25 carcass rinses during pre-chill processing, 25 carcass rinses during post-chill processing, and 50 samples from exudates from carcasses stored at 4°C (25 after 2-day storage and 25 after 6 day storage). Each sample type was cultured for Campylobacter spp. Isolates recovered from positive samples were subtyped using flaA SVR (flagellin A-short variable region) DNA sequence typing and compared for relatedness. The data demonstrated that multiple subtypes of C. jejuni were present in a flock, and that subtypes present in a flock during production were also present on the final processed product. Subtypes recovered by the two recovery methodologies were similar based on flaA SVR classification. Combining the totals from all 3 flocks a total of 14 flaA SVR subtypes were recovered from post-chill carcass rinses and 12 subtypes recovered from 6-day exudate samples.