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代写辅导接单-ENVH7001 --Assignment 1

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ENVH7001

Assignment 1 – QMRA: Problem Identification and Exposure Assessment report

Due date: 25th Mar 5pm, online submission on Turnitin via Blackboard.

Assignment

Recently, a lettuce farm in Brisbane was exposed to flash flooding caused by ex-Tropical

Cyclone Alfred. Although the floodwaters receded within two days, there is concern that

some of the lettuce may have been contaminated by the floodwater. Despite this

uncertainty, the farmers proceeded to harvest the lettuce once it reached maturity. The

harvested lettuce was washed and cleaned using rainwater collected on the farm to

remove dirt and debris. It was then packaged and prepared for transport to retailers.

Historically, flood-contaminated and uncooked lettuce have been associated with a high

risk of transmitting various diseases. To ensure food safety, the State Government food

handling authorities have required the farmers to conduct a first-tier QMRA, covering no

fewer than three pathogens, to evaluate the biological risks and determine whether

additional control measures are necessary to prevent disease.

The farmers have engaged your services to help establish the first two steps of the QMRA

framework, problem identification and exposure assessment, for presentation at a

meeting with the licensing authorities. Your task is to assess the exposure risk for an

average adult consuming fresh lettuce salad harvested from the farm.

Prepare a report addressing the following:

1. Problem Identification – Clearly define the potential hazards, including the

pathogens of concern and the possible routes of contamination.

2. Exposure Assessment – Estimate the potential exposure level of an average adult

to the identified pathogens through the consumption of the lettuce.

Ensure that your report follows a structured format and includes evidence-based

reasoning to support your analysis.

Report structure

Maximum 6 pages, excluding references, following the structure below:

Executive summary (max. 1 page, within page limit)

Short summary of the report, including objectives, summary of problem

identification and exposure assessment approach and major conclusions.

Introduction (max. 1/2 page, within page limit)

• Brief description of the scenario and introduction to the objectives of the

report.

Problem Identification (approx. 1 page, within page limit)

Formulate hazard identification including, but not limited to, the points below:

3.1. Define the scope and purpose of the study

• Define the problem’s boundaries from source to exposure

• Describe the lettuce production process using a block diagram.

3.2. Hazard identification

• Identify the pathogens, and/or indicative pathogens, and relevant information

including optimal conditions of survival, etc

• Describe the hazardous event

3.3. Exposure pathway

• Identify the exposure pathway

• Time frame between source and exposure (compare with pathogen survival)

• Potential growth that can happen between the source and the point of

exposure and implications in product packaging and transport conditions.

3.4. Health outcomes

• Identification of health concern (illness), duration, incubation time, etc.

• Any relevant costs and/or legislation considerations

3.5. Identify the risk management decision that has to be made

4. Exposure assessment (approx. 2 page, within page limit)

4.1. Source: report on relevant information and data to calculate the exposure

concentration C

• Identify possible source(s) of contamination.

• Pathogen exposure: Find ranges of values in literature from similar reports to

obtain occurrence data for the pathogen(s) and/or reference pathogen(s)

identified.

• Compare the pathogen values in this scenario with values found in literature

for similar cases (lettuce or other vegetables for raw consumption).

4.2. Intake: report on relevant information and data to calculate the ingested

quantity q per unit of time

• Define the frequency (single event, recurrent event – frequency) and unit of

exposure (amount ingested or inhaled, contact extension, number of vectors,

etc)

• Note 1: Not all of the listed elements in the items above are applicable to this

case study (e.g. lettuce tends to be ingested, not inhaled) – choose the

elements relevant to the pathogens that you identify relevant in the references

used).

• Note 2: You must search and obtain information and data for your risk

assessment using publicly available resources. Since this is a hypothetical

situation (as often is the case when trying to prevent risk before accidents

happen), you have to find typical ranges from literature and use them in your

calculation. Beware that all data must be supported by adequate

referencing, otherwise that section will not be considered valid.

• Note 3: Clearly state all assumptions made

• Note 4: in this assignment we only focus on these two first steps of the QMRA

framework. Identification of the dose-response profiles and subsequent risk

analysis and management actions will be covered in the next assignments.

Results (approx. 1/2 page, within page limit)

• Quantification of the magnitude and frequency of exposure (i.e. exposure

dose) for each of the pathogens identified in the steps above, taking into

account the considerations of the scenario and assumptions made.

• Clearly state all the steps used for these calculations.

Discussion and conclusions (approx. 1 page, within page limit)

• Critically analyse and discuss the situation and the results.

• Include a qualitative discussion about the reliability of the data sources and

implication of the results.

• Compare the results obtained with other values found in literature for lettuce

or other vegetables intended for raw consumption.

• Discuss the adequacy of the processing steps used in the lettuce production

process. Include also any other potential points of contamination identified in

your report.

7. References (no limit)

Use UQ recommended referencing style:

https://guides.library.uq.edu.au/referencing

Formatting

• Use one of the following fonts: Calibri 11pt, Times New Roman 12pt, Arial 11pt.

• Make sure all tables and figures have a caption. Captions should appear above

Tables and below Figures.

• All values used in the report must be adequately referenced (see point 7)