+1-817-968-5551
+61-488-839-671
+44-7480-542904About Expert
Key Topics
- Requirement
- Solution
- A. Identify the different reasons for microbiological testing of the named product .
- B. Explain the approach you would take in determining the organisms you would include in the test regime
- C. Identify and characterize the organisms you would test for, with your rationale for their inclusion and an indication of when you would test
- D. Produce outline microbiological laboratory procedures for three of the organisms you have selected, including a pathogen, a quality indicator and an indicator of poor hygiene practice
- References
Requirement
Microbiological assessment of Ready-to-eat salad
Solution
A. Identify the different reasons for microbiological testing of the named product.
The products ready-to-eat (RTE) salads consist of numerous nutritional components. The components include cows' milk, wheat flour, asparagus, egg, cheese, butter, water, salmon, onion, corn flour, salt, mustard, rapeseed oil etc. Due to advancements and lack of adequate time, the personnel depends on RTEs. The salads are processing, preserving, packaging and distribution under controlled conditions can facilitate the consumers for consumption. As the RTEs are ready for consumption and contain diverse nutrients, which are likely to be attracted by microorganism, adequate measures shall be taken for the quality of products (FAO/WHO, 2008). The following are the reasons for which the products shall be subjected for microbiological testing
-
The stuff of RTE may contain diverse microorganisms. The microbes may harm the individual if the RTE contain the pathogenic microbes
-
Ingestion of pathogens or toxins that result in infection and/or the production of toxic by-products in the human gut.
-
RTE contain ingredients with specific nutritional values. The presence of microbes can consume the ingredients can lead to substandard RTEs. So the identification by microbiological testing can sort the quality of product
-
The testing help in assessing the shelf life of the product can be assessed. For instance the fungal population from a RET salad has been tested during a shelf-life (Ugo, 2012)
-
Aids in the assessment of risk based on the quantitative estimation. The quantitative microbial risk assessment is a rapid development program in the assessment of food safety (Crepet et al., 2007).
-
Facilitates the raw and RTE for the extent of contamination in specific area and use of outcome for safe preservation of RTE (Kaneko et al., 1999)
-
The type of contamination i.e., bacterial, fungal, viral etc can be identified using microbiological testing
-
The testes are done to identify the sources of contamination from which it originates and to check the compliance of the used material
-
Based on the microbiological testing the quality of RTE can be assessed and an assurance for the safety can be assigned
-
The quality control monitoring of the RTE as a in process and for finished product serves in controlling the product performance.
-
The tests are required for routine production of RTEs and based on which, the products can be released into market.
-
The products which fail to comply the specifications can be prevented from marketing
-
Post marketing surveillance: Microbiological testing of RTEs apart from other quality control testes serves in minimizing the risk towards the heat of consumers. If any contamination observed due to diverse reasons, the products can be withdrawn from the market
-
The extent of harm can be assed based on the pathogenicity of the contaminations.
-
Target Tolerance: The pathogenic tolerance can be assessed in order to determine the impact of stuff on health. Periodic inspection programs via microbiological testing is needed to check the lot to lot variations in terms of quality of the material
-
Based on microbiological testing, specifications can be prepared for comparison of microbial load from the RTE during production, shelf till consumption periodically
You can get the best biology assignment help at Allassignmenthelp.com because we cover a wide range of subjects in this field. If you believe you are stuck with a marine biology assignment help, we are here to assist you. We cover all of the major branches of science in our cheap assignment writing service, including physics, chemistry, and biology.
B. Explain the approach you would take in determining the organisms you would include in the test regime
The foodstuff so called as RTE that are sold in designated open markets and around the main academic departments would be selected for the study. Therefore, this study aimed to analyse the bacteriological quality of ready-to-eat foods sold in various parts of the university campus and to compare the quality of foods sold from the open markets to the restaurants. A sample of about 100 g will be carefully collected and transferred into the sample containers, which were covered tightly, labeled and transported, on ice to prevent bacterial multiplication during sample transportation to the Bacteriology Department, where the analysis was done on the same day. The food item so called salad is shown in Table-1
Table-1: Qualitative composition of RTE
Method: The RTE will be examined for the following
o An Aerobic Colony Count (ACC): The quality of RTE from microbial perceptive and effectiveness for sanitation
o Indicator organisms
o Food borne pathogens will be identified to assess the safety of RTE for human consumption. The microbiological testing for RTE should be appropriate to the type of food sample being examined and to processing, it has received. A list of microbes to be targeted is shown in Table-2. After inoculation and culturing, the microbial load will be estimated for further interpretation. The interpretation of results will be based on knowledge of the product components and the production process.
Table-2: Proposed guidelines for microbes for RTEs (Health Canada, 2010)
Bacterial Counts: The RTE so collected will be macerated (10 g) in about 90 mL of phosphate buffered saline to make a 1:10 dilution. Serial dilutions will be made and examined by means of the pour plate method (Mensah et al., 2002). Each plate will be labelled on top and 100 μL of diluted samples to be analysed will be pipette into the plate. Accurately measured 25 mL of molten agar (after cooling) will be poured over the medium. The medium will be allowed to set on a flat-top bench, after which plates will be incubated aerobically at 37°C. Plate count agar will be used for the enumeration of aerobic colony counts. Species Identification: About 40 mL diluted sample will be placed in a centrifuge tube and centrifuged at 25000 rpm for 15 min in a refrigerated centrifuge. The supernatant will be discarded and the pellets will be directly streaked onto differential media for the detection of Salmonella sp., E. coli and other Enterobacteriacea. Suspected bacterial colonies from all the plates will be sub cultured on specific media to obtain pure cultures for morphological and biochemical identification. The count of the microorganisms after isolation and purification will be done microscopically. The data will be interpreted as follows
No organism detection is desired to say the RTE is clean and can be readily consumed. The microbial load below 100 CFU per gram is desirable to say the RTE is no harm and can be used for human consumption. The potentially hazardous levels of V. cholerae should be considered and caution can be given to avoid for consumption. In addition the categorization
o Category 1: These foods are ready-to-eat and are comprised entirely of components that have been cooked in the preparation of the final product without subsequent handling or processing of any kind prior to distribution or sale (ex. soups, bread, quiche, cooked meat, fish & seafood and vegetables).
o Category 2: These foods contain some components that have been cooked, but may have been further handled prior to or during the preparation of the final product. This category also applies to any foods that are assembled from ready-to-eat foods (excluding those in category 3) that are not subsequently cooked (ex. hot dogs, sandwiches, burgers)
o Category 3: Examples of foods in this category are foods such as fresh fruits or vegetables, deli meats, fermented foods, chicken salad, tubule, all kind of sprouts and cultured dairy products or any food product incorporating these foods (such as sandwiches), where it is expected that high standard (aerobic) colony counts would be present due to the normal microbial flora associated with these items. As such, ACC does not apply (ex. pitas, potato or pasta salad, salad rolls)
o Satisfactory: test results below detectable levels indicate good microbiological quality and further action is not required.
o Unsatisfactory: Test results are outside of the accepted microbiological limits and are indicative of problems with sanitation, maintenance, food handling and/or food storage practices. Immediate action is required. Actions may include, but should not be limited to: the withdrawal of food from the same lot, the same day production and perhaps the same nature depending on results. Further sampling is required and an investigation of food handling and sanitation controls is warranted.
o Potentially Hazardous: Test results in a range approach those implicated in outbreaks of food borne illness and immediate action is required. Actions may include, but should not be limited to: the withdrawal of any food still available for sale or distribution, the recall of foods already sold or distributed to the public; the re-sampling of food(s); an investigation of food handling, storage, display and/or receiving practices; a review of sanitation, maintenance, hygiene, exclusion, and/or pest control measures, and any other action the EHO deems necessary to determine the source of the contamination and mitigate further risk to the public.
C. Identify and characterize the organisms you would test for, with your rationale for their inclusion and an indication of when you would test
Considering the pathogenicity of organisms, the following are identified as the harmful microbes for human. Therefore, the presence of the bacteria needs to be identified and accordingly precautions are to be taken to control them in the RTE
Salmonella Sp: Pathogenic salmonellae ingested in food survive passage through the gastric acid barrier and invade the mucosa of the small and large intestine and produce toxins. Invasion of epithelial cells stimulates the release of proinflammatory cytokines, which induce an inflammatory reaction. The acute inflammatory response causes diarrhoea and may lead to ulceration and destruction of the mucosa. The bacteria can disseminate from the intestines to cause systemic disease (Giannella, 1996). Therefore, the presence of pathogenic salmonella needs to be done using an appropriate test. The diagnosis of salmonellosis requires bacteriologic isolation of the organisms from RTE. Laboratory identification of the genus Salmonella is done by biochemical tests; the serologic type is confirmed by serologic testing. The sample cab be plated on several nonselective and selective agar media (blood, MacConkey, eosin-methylene blue, bismuth sulfite, Salmonella-Shigella, and brilliant green agars) as well as into enrichment broth such as selenite or tetrathionate. Any growth in enrichment broth is subsequently subculture onto the various agars. The biochemical reactions of suspicious colonies are then determined on triple sugar iron agar and lysine-iron agar, and a presumptive identification is made. In addition, the characterization can be done by biochemical identification of Salmonella can be confirmed by antigenic analysis of O and H antigens using polyvalent and specific antisera.
V Cholera: Cholera is transmitted by the contaminated RTE with feces. Vibrios are sensitive to acid, and most die in the stomach. Surviving virulent organisms may adhere to and colonize the small bowel, where they secrete the potent cholera enterotoxin. This toxin binds to the plasma membrane of intestinal epithelial cells and releases an enzymatically active subunit that causes a rise in cyclic adenosine 51-monophosphate production. The resulting high intracellular cAMP level causes massive secretion of electrolytes and water into the intestinal lumen. Abundant loss of electrolytes could cause abnormalities in circulatory system and eventually influence the life of person. Therefore, the monitoring of V Cholera has to be done. For rapid diagnosis, the foodstuff is examined microscopically. The characteristic motility of vibrios is stopped by specific antisomatic antibody. Other methods are culture of RTE swab samples on TCBS agar and other selective and nonselective media; the slide agglutination test of colonies with specific antiserum; fermentation tests (oxidase positive); and enrichment in peptone broth followed by fluorescent antibody tests, culture, or retrospective serologic diagnosis. In addition, the polymerase chain reactions can characterize molecularly, the presence of V Cholera (Finkelstein, 1996).
Staphylococci Sp: S aureus expresses many potential virulence factors. (i) Surface proteins that promote colonization of host tissues. (ii) Factors that probably inhibit phagocytosis (capsule, immunoglobulin binding protein A). (iii) Toxins that damage host tissues and cause disease symptoms. Coagulase-negative staphylococci are normally less virulent and express fewer virulence factors. S epidermidis readily colonizes implanted devices. The presence of staphylococci can be determined by the presence of clumping factor, coagulase, hemolysins and thermostable deoxyribonucleic are routinely used to identify S aureus (Foster, 1996). The characterization can be done using the tests as outlined in Table-3
Table-3: Summary of confirmatory tests for Staphylococci Sp
D. Produce outline microbiological laboratory procedures for three of the organisms you have selected, including a pathogen, a quality indicator and an indicator of poor hygiene practice
The microbe, Salmonella is identified as the pathogenic organism and the microbiological laboratory procedure as follows
The example might be gathered from RTE with the assistance of a clean surgical blade, blade, spoon or other apparatus cut little pieces from delegate locales of RTE to set up a composite specimen bit. Item with the meat/poultry segment separate from any vegetable/dessert part, or fajita units with meat/poultry, onions/peppers, and tortillas in three separate inner bundles/sacks inside of an external bundle. Whenever meat/poultry is joined with different fixings to shape the item (e.g., hamburger stew containing vegetables, potatoes, and so on.), examination will be defeated meat/poultry bits in blend with different fixings. The composite will be precisely weighted into a huge sterile sack. Around 1/3 bit of supported peptone water (BPW) will be included trailed by the disturbance and expansion of rest of BPW. Brood at 35 ± 2°C for 18-24 h. Exchange around 0.5 ± 0.05 ml of test into 10 ml TT juices and 0.1 ± 0.02 ml into 10 ml mRV soup. Hatch at 42 ± 0.5°C for 22-24 h or in a water shower at 42 ± 0.5°C for 18-24 h. Painstakingly blend substance of tube by vortexing or identical means. Streak to Brilliant green sulfa agar and either twofold altered lysine iron agar or Xylose lysine Tergitol™ 4 agar plates utilizing a 10 µL loopful of inoculum for every plate. Mark the whole agar plate with a solitary example improvement and hatch at 35 ± 2°C for 18-24 h. States so developed will be chosen and separated from the plate. After the suggested hatching interim, inspect the particular differential agar plates and controls for the vicinity of states meeting the depiction for suspect Salmonella provinces. Pick all around secluded settlements. Select states that are pink and obscure with a smooth appearance and whole edge encompassed by a red shading in the medium. On extremely swarmed plates, search for provinces that give a tan appearance against a green foundation. Second, select dark settlements (H2S-positive) or red states with (H2Spositive) or without (H2S-negative) dark focuses. The edge of the state might in any case be yellow in 24 h; later it ought to turn red. Third, select purple settlements with (H2S-positive) or without (H2Snegative) dark focuses. Since salmonella commonly decarboxylate lysine and mature neither lactose nor sucrose, the shade of the medium returns to purple (Laboratory Guidebook, 2013).
Quality marker: The organism, E Coli can be considered as the quality pointer in surveying the nature of RTE. Bacterial determinations will be done in twofold utilizing the standard culture techniques. The strategy involves ten grams of every example from a 90 mL of Buffered Peptone Water. Serial dilutions will be made for suspension utilizing BPW and dissected for E Coli utilizing T.B.X. medium. The vaccinated plates will be incubated at 30 °C for 24-48 h and at 44 °C for 24h separately (De Giusti et al., 2014).
Poor hygiene because of undercooking, or cross tainting from crude meat, sustenance handlers or nourishment contact surfaces and also poor temperature and time controls. The pollution of sustenance by enteric pathogens can happen from the homestead if human sewage is utilized to treat the dirt or if sewage water is utilized to inundate the harvests. Such dangers are further expanded if the nourishment is misused amid handling and arrangements where pathogens could increase exponentially under positive conditions (Ghosh et al., 2007). The RTE will be handled by scattering allocate in sterile water and couple of miniaturized scale litres of test will be vaccinated into tubes containing 2.5 ml of Trypticase Soy Broth. After brooding for 3 to 5 hr at 35o C, the development was vaccinated into sets of media and substrates. Parts of MacConkey agar without gem violet will be streaked for control purposes. Gelatin strips will be added to the rest of the first development in TSB. The pathogenic organisms having a place with enterobacteriacae will be subculture to blood agar after preparatory serological screening keeping in mind the end goal to portray further for affirmation (Traub et al., 1970).
Place Order For A Top Grade Assignment Now
We have some amazing discount offers running for the students
Place Your OrderReferences
-
Crépet, A., Albert, I., Dervin, C., & Carlin, F. (2007). Estimation of Microbial Contamination of Food from Prevalence and Concentration Data: Application toListeria monocytogenes in Fresh Vegetables . Applied and Environmental Microbiology, 73(1), 250–258.
-
De Giusti, M., Solimini, AG., Cottarelli, A., De Vito, C., Aurigemma, C., Tufi, D., Piccinato, L., Boccia, A & Marinelli, L (2014) Temporal pattern of microbial indicators of ready-to-eat rocket salads during shelf life. Ann Ist Super Sanita. 50(1), 90-95
-
FAO/WHO (2008) Food and agriculture organization/World Health Organization. Microbiological hazards in fresh fruits and vegetables. Pre-publication version. Microbiological Risk Assessment Series
-
Finkelstein, RA (1996) Cholera, Vibrio cholerae O1 and O139, and Other Pathogenic Vibrios. In: Baron, S., editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston. Available from: http://www.ncbi.nlm.nih.gov/books/NBK8407/
-
Foster, T (1996) Staphylococcus. In: Baron, S., editor. Medical microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston. Available from: http://www.ncbi.nlm.nih.gov/books/NBK8448/
-
Ghosh, M., Wahi, S., Kumar, M & Ganguli, A (2007) Prevalence of enterotoxigenic Staphylococcus aureus and Shigella spp. in some raw street vended Indian foods. Int J Environ Health Res. 17(2), 151-6
-
Giannella, RA (1996) Salmonella. In: Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston. Available from http://www.ncbi.nlm.nih.gov/books/NBK8435/
-
Health Canada (2010) Microbial guidelines for Ready-to-Eat foods Retrieved from http://publications.gc.ca/collections/collection_2014/sc-hc/H164-167-2013-eng.pdf
-
Kaneko, KI., Hayashidani, H., Ohtomo, Y., Kosuge, J., Kato, M., Takahashi, K., Shiraki, Y & Ogawa, M (1999) Bacterial contamination of ready-to-eat foods and fresh products in retail shops and food factories. J Food Prot. 62(6), 644-9.
-
Laboratory Guidebook (30-Sep-2013) Retrieved from http://www.fsis.usda.gov/wps/wcm/connect/700c05fe-06a2-492a-a6e1-3357f7701f52/MLG-4.pdf?MOD=AJPERES
-
Mensah, P., Yeboah-Manu, D., Owusu-Darko, K & Ablordey, A (2002) Street foods in Accra, Ghana: How safe are they?. Bull. World Health Organiz., 80, 546-554
-
Traub, W. H., Raymond, E. A., & Linehan, J. (1970). Identification of Enterobacteriaceae in the clinical microbiology laboratory. Applied Microbiology, 20(3), 303–308.
-
Ugo, DC (2012) Fungal population dynamics in Ready-to-eat salads during a shelf-life in Italy Journal of Agricultural Science and Technology A2, 569-576
Give your grades a boost
Just share your requirements and get customized solutions on time.
-
1,168,768 Orders
-
4.9/5 Overall Rating
-
5,052 Experts
