الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
SUMMARY
The present study has focused on four major bacterial pathogens that commonly cause foodborne diseases which can be transmitted through poultry products.
Assuring food safety, particularly as regards to microbial contaminants, as it’s still a very complex issue. Early detection of these very serious foodborne pathogenic bacteria in the poultry processing plants is important to ensure consumers’ safety. Most of the laboratory techniques discussed here to detect certain pathogens in poultry parts require an enrichment step. Furthermore, all detection methods showed good sensitivity for most of pathogens except for Campylobacter spp. but they are still too expensive to be a mainstream use.
In addition, all of the studied methods need well trained laboratory staff to do all the steps and interpretate the results, which makes the application of widespread of these methods and non-expert staff is too difficult.
Nevertheless, since there is no single approach satisfies all the criteria for rapid, effective, reproducible and sensitive results, a detection and identification of microbes in the food chain is necessary for both eliminating the frequency of foodborne outbreaks and food loss due to microbial spoilage.
A total of 174 samples were collected from 2 semi-automated poultry slaughterhouses setting, each setting is connected to specific poultry farm. Several types of microbiology samples were collected including swabs, chicken parts and carcass. Samples were collected from the whole chain starting from receiving area to the end product.
The laboratory testing was conducts to diagnosed the most important foodborne pathogenic bacteria including Sta. aureus, Shigella spp., Salmonella spp., and Campylobacter spp. in this study we have used 4 laboratory testing techniques including conventional detection method by various types of culture media and biochemical testing, immunoassay method using VIDAS system, molecular detection by PCR, and BD Phoenix M50 as an automated identification system to confirm the isolates. Pre-enrichment step was done according to each targeted bacterium.
The plate count for studied samples were observed for aerobic bacterial growth and the samples showed high number of colonies as contaminated at levels exceeding limits by food regulatory bodies, a reflection of the condition of the whole carcass meant for human consumption.
6.1. Total number of detected microorganisms from both sites by different methods:
6.1.1. Detection of Staphylococcus aureus:
In general, the detection rate of Sta. aureus from both sites was 50 and 44 out of 174 collected samples detected by PCR and immunoassay respectively. Whereas the conventional method detected 36 isolates out of 174 collected samples and all of the isolates have been confirmed by the automated system.
6.1.2. Detection of Shigella spp.:
The detection rate from both sites have reached 13 out of 174 samples detected by PCR while the conventional detection method detected 7 isolates only out of 174 samples and same number were confirmed by the automated system as Shi. flexneri. There was no immunoassay available to evaluate Shigella spp. detection.
6.1.3. Detection of Salmonella spp.:
from both sites the Salmonella spp. detection rate have reached 73 out of 174 collected samples using the PCR technique followed by immunoassay detected 53. Meanwhile, the conventional detection method detected 50 isolates and same number were confirmed by the automated system.
The most common Salmonella isolates were Sal. enterica 70% that confirmed by the automated system.
6.1.4. Detection of Campylobacter spp.:
from both sites were able to detect 61 Campylobacter spp. by PCR followed by immunoassay detected 51 while the conventional detection method was able only to detect 17 out of 174 as C. jejuni. The automated system doesn’t have the capability to identify Campylobacter spp.
6.2. Detection rate across the critical control points from 2 sites:
6.2.1. Detection of Staphylococcus aureus:
The detection of Sta. aureus from site 1 across the different critical control points was different and increasing over the production line with highest rate at CCP 6 which means that there was no much focus on contamination control during the packaging step that made the poultry parts gained the pollutant bacteria.
Although, molecular detection method was able to detect 31 isolates out of 91 tested samples and immunoassay method was able to detect 27 and the least detection rate was by conventional detection method 22 using spot testing and confirmed by automated system.
On the other hand, for site 2, the detection rate of Sta. aureus across the different critical control points was very close to each other and almost equally distributed over the production line with highest rate at CCP 5. That includes, molecular detection method was 19 out of 83 tested samples and for immunoassay method was 17 and the only 14 isolated by conventional method and confirmed by automated system.
6.2.2. Detection of Shigella spp.:
The detection rate of Shigella spp. from site 1 across the different critical control points was very low and limited only to 3 points which is CCP 1, 3, and 4 of the production line.
Whereas, the molecular detection method was able to detect 10 out of 91 tested samples and 5 by conventional detection method using the biochemical testing tubes and confirmed by automated system as Shi. flexneri.
However, for site 2 the detection rate of Shigella spp. across the different critical control points was almost having same trend and detection was limited to CCP 2, 3, and 6 of the production line.
Whereas, molecular detection method was 3 out of 83 tested samples and 2 isolated by conventional method as Shigella spp. and confirmed by automated system as Shi. flexneri.
6.2.3. Detection of Salmonella spp.:
The detection rate in site 1 for Salmonella spp. across the different critical control points was a bit high at early CCPs then decreased at the last point which shows some infection control. The highest rate was at CCP 5 detected by different methods including molecular detection method was 41 out of 91 tested samples and 34 by immunoassay method then the least by conventional detection method was 30 using biochemical testing tubes that identified as Salmonella spp. and confirm 23 (77%) of the isolates as Sal. enterica by automated system and the rest as Salmonella spp. requiring serotyping identification.
Although, for site 2, the Salmonella spp. detection rate across the different critical control points was high at the first 5 points then decreased at the last point. The highest rate was at CCP 5 detected by different methods.
Whereas, the molecular detection method was 32 out of 83 tested samples and immunoassay method was 24 and the least by conventional detection method was 20 using biochemical testing tubes identified as Salmonella spp. and confirm 12 (60%) of the isolates as Sal. enterica by automated system and the rest as Salmonella spp. requiring serotyping identification.
6.2.4. Detection of Campylobacter spp.:
In general, for site 1 the detection rate of Campylobacter spp. across the different critical control points was very minimal and distributed over the different CCPs of the production line. That includes 35 out of 91 tested samples by molecular detection method and 29 by immunoassay method while the least by conventional detection method was 10 using spot testing and identified as C. jejuni.
While, for site 2 the detection rate of Campylobacter spp. across the different critical control points was moderate and distributed over the different CCPs of the production line. That includes, 29 out of 83 tested samples by molecular detection method and 22 by immunoassay method and 7 isolated by conventional detection method using the spot testing and identified as C. jejuni.
6.3. Detection of co-infections by different methods:
In combination of all results for studied microorganisms and detected at the first site, mostly the detected pollutant was single infection with one of the studied microorganisms (Sta. aureus, Shigella spp., Salmonella spp., and Campylobacter spp.) and this applies to all detection methods.
Moreover, from the first site the molecular method was able to detect 25 dual infections compared to immunoassay that detected 19 dual infections as well as 13 dual infections were detected by conventional detection method. In addition, only one sample had triple infections detected by conventional method and 6 samples detected by immunoassay. As well as, one sample had four infections of microorganisms.
Same for second site, the majority of detection was single infection with one of the studied microorganisms which applies to all detection methods. The highest rate was detected by conventional detection method 23 of single infection followed by molecular method detected 19 of single infections while only 18 of single infection was detected by the immunoassay.
In the meantime, the molecular method was able to detect 20 dual infections compared to other methods. Also, immunoassay method was able to detected 18 dual infections while the conventional detection method was able to detect 13 dual infections only. At the same time, the molecular method was able to detect 7 triple infections and the immunoassay method was able to detect 3 samples with triple infections.
6.4. Other studied factors:
The turn-around-time and cost per test were studied to consider the economic impact. Significantly, the automated detection system was shortened in time of detection for Salmonella spp. and Shigella spp. while for detection of Sta. aureus was longer than conventional detection method. Also, the immunoassay method was shorter to detect Salmonella spp., Campylobacter spp., and Sta. aureus than conventional method, while the TAT for molecular testing was the shortest for all studied microorganisms.
Meanwhile, the automated identification method was the costliest method followed by the immunoassay method and the cheapest method was the conventional detection but still it takes the longest detection time compared to other detection methods.
6.5. RECOMENDATIONS
Certainly, national control strategies are needed to avoid spreading of pathogenic bacteria in all poultry production phases using either mechanical controls and/or adding natural substances at certain point to improve its sanitation. The study recommends using a combination of two methods like the conventional detection method combined with a rapid confirmation device for bacterial isolates when applicable to improve the testing accuracy, sensitivity, and specificity of the detection method.
Meanwhile, more studies should be done for using different preservation methods (e.g., Low level of herbs, irradiation doses, high hydrostatic pressure, and Bio-preservatives). These methods can be used alone or combining two methods where it can mitigate the foodborne pathogens in poultry products, saves the quality of poultry meat, and reduce the contamination that could happens during the production.