Experts

HKUST Campus Safety Office

      We discussed various aspects of food safety and preventive measures at HKUST with Professor Sit. We knew that heating does not kill the bacteria B. cereus, which can contaminate not only rice but also other foods. Professor Sit said the source and packaging of food are important factors in preventing contamination. The CSO follows the HACCP system and conducts quality control measures, particularly focusing on water, ice, and critical points for food vendors. Testing for B. cereus is challenging, but regular lab tests are conducted for generic bacteria. HKUST has HACCP certification for many of its restaurants, and inspections are carried out annually. In the event of food poisoning outbreaks, lab reports are required from the affected restaurants. The CSO monitors food safety, refrains from providing high-risk products before exams, and conducts inspections based on the frequency of food poisoning cases. The quality of workers and samples is occasionally checked, and reputable labs are used for inspections. Professor Sit discussed with us the use of a test kit for instant results as well as the possibility of improving food-checking protocols through an app. Increasing awareness of B. cereus and other contaminants is a challenge, and raising awareness through restaurants is not practical. All in all, Professor Sit highlighted and reminded the importance of food safety protocols and the need for ongoing monitoring and improvement in the future.

Figure 1 Zoom meeting with Professor Sit from HKUST Campus Safety Office

HKUST Health, Safety and Environment Office (HSEO)

      Professor Yu is a health, safety and environment expert with 30 years of experience. He had also been on the iGEM safety committee. We consulted the biosafety of using whole cell biosensor. He gave us many valuable directions, including asking us to collect opinions from different stakeholders. So, we started collecting public opinion through surveys, to find out whether the end-users would be willing to use a test kit with GM Bacteria. and started interviewing restaurants. We also started considering safety for disposal of the test kit.

Figure 2 Meeting with Professor Yu from HKUST HSEO

Hardware Research

      We consulted Professor Marshal Liu who specializes in food technology and bioproducts, and he suggested we could make a capsule design for biosafety and try to use household keeping that users already owned, such as ethanol for extraction and bleach/Dettol, for disinfection.

Figure 3 Meeting with Professor Marshal Liu

      Before biosensor engineering, we had concerns about whether the performance of the biosensor cells would be affected by the gel matrix. After consulting with Professor Sun Fei of the HKUST Chemical and Biological Engineering(CBE) Department, who specializes in Bioengineering and Biomaterial development, the following advice solved our concerns:

  • B. Subtilis spores can survive under an anaerobic environment so capsules in hydrogel solution, or even anaerobic capsule design would not affect their growth and function.
  • B. Subtilis spores are robust enough to be immobilized in gel and be reactivated with nutrient supply, fluorescence protein signal would not be affected much as well.
    • Figure 4 Professor Sun Fei

          During the engineering process, we embedded Engineering Cycle 0 sporulated B. Subtilis Cells engineered and tested working into gel. However, the fluorescence signals were not significantly given out upon adding valinomycin. Therefore, we also consulted Mr. Kachin Wong, CEO of SPES Tech, who specialized in hydrogel cell culturing. We are grateful for the following list of advice from him:

  • The scale of the biosensor and the concentration of cells could be factors contributing to insufficient fluorescence.
  • For obtaining better signal from plate reader scanning:
  • Try making gels with smaller diameters but keeping the same volume of the gel-cell mixture. You can try using a smaller mold, it could be 24 well plates, instead of 12 well plates.
  • Try using cell culture with higher OD before adding to the gel solution.

    •       We then adjusted the protocol by using B. Subtilis spores that had been incubated for a longer time and made gels within 24-well plates with the same volume of the gel-cell mixture(1500uL), and we successfully obtained the result that proves fluorescent signal could significantly increase upon 3uM Valinomycin added.

    Figure 5 Meeting with Mr. Kachin Wong

    Modeling Research

    Cereunotes

    Key Questions & Findings

    1. Model fitting Strategies
    2. Sensitivity analysis
    3. Modeling Cereulide Distribution in rice

    Key Actions

    1. Search for larger range of parameters space before doing local optimization
    2. Try chunking the model to do the sensitivity analysis
    3. Statistical approach for cereulide distribution in rice
    Introduction to Drylab External Support

          Due to the highly technical nature of our modeling endeavors, we sought advice from Professor Henry Lam of our very own HKUST. Professor Henry is currently an Associate Head and Professor of the Department of Chemical and Biological Engineering. His expertise in Modeling is primarily useful in helping us find solutions to other parallel projects such as Sensitivity Analysis and Cereulide Distribution Modeling.

    1st Meeting with Henry Lam

    Our meeting with Professor Henry primarily aimed to answer a few questions:

    1. How do we optimize the Sensitvity Analysis of our model?
    2. How should we go about modeling B. Cereus Spore Distribution?

    Succinctly, here is a general summary of the answer we got:

    1. For Sensitivity Analysis:
      1. Problem: The model takes too long to run and there is a high amount of uncertainty from unknown variance.
      2. Suggestions: Try chunking the model in order to increase run times without sacrificing accuracy. Chunking involves the breaking apart of a model into smaller components and running them as you would a complete circuit. As for the high amount of uncertainty, it is normal that there is some level of unexplained variance that comes from noise but there ought to be a threshold percentage of unexplained variance that, if exceeded, the result of the analysis should not be accepted. To remedy, either analyze the model for errors or approach the sensitivity analysis differently.
    2. For Bacterial Distribution:
      1. Problem: How do we go about modeling Cereulide Distribution in food material?
      2. Suggestions: A 2D/3D can be created storing a random coordinate value (x, y) of B. Cereus. As germination occurs, new coordinates can be appended to the list, creating a comprehensive table of bacterial positions. Then perform a statistical analysis of cereulide distributions, in another random position to observe spread.
    Figure 6 Zoom meeting with Professor Henry Lam
    2nd Meeting with Henry Lam
    1. Circuit Modeling: Model fitting
      1. Suggestions: Before doing the fitting, we should tune the curve to a similar shape with the experimental data, such as finding possible parameter space first. This gives us the idea of using GA to do the fitting first. (Check circuit modeling)
    2. Cereulide production with respect to time modeling
      1. Suggestions: If the temperature cooling effect is not significant, we can neglect it and simply model it under constant temperature.

    Meeting with Mr. Jun Lam from SEAMART

          SEAMART is a food manufacturer providing food boxes of ISO standards, party food, and hot pot toppings. Mr. Lam kindly shared with us the practices of his food box preparation industry, for example, keeping the food boxes' rice center temperature at 56 degrees Celsius to ensure the good quality of food boxes distributed. We are very happy to hear that Mr. Lam knows toxins that could arise due to improper cooling and the keeping-warm practices of SEAMART can effectively prevent the production of cereulide by B. cereus.

    Figure 7 Meeting with Mr. Jun Lam from SEAMART

    Businesses and NGOs

    Volunteering with Food Angel

    Cereunotes

    Key Questions

    1. How does Food Angel prepare and produce food boxes in large batches?
    2. What are the quality control procedures for Food Angel?
    3. How is food safety maintained throughout the food production process?

    Key Findings

    1. Food Angel has large food processing centers which prepare different types of food, from vegetables to seafood.
    2. Food Angel has high quality control standards, monitoring different steps in the production closely to prevent any bacteria proliferation.
    3. Proper protective gear and food safety protocols help Food Angel staff avoid food contamination.

    Key Actions

    1. Enjoy the volunteering experience at Food Angel
    2. Think about when to use the test kit in the food production chain.

          Food Angel is one of the largest non-profit organizations in Hong Kong that assists in distributing leftover foods from restaurants or supermarkets to those in need. They would collect such foods in large batches, and prepare food boxes for distribution. Our team had the privilege to aid in one of their volunteering events, in which we went to their food processing centers and helped prepare different types of food such as vegetables and seafood. We also had the opportunity to have a chat with a quality control expert after our event. We were able to gain much more insight into how their centers practice food safety measures, and how aware they were of various types of food handling procedures which would eliminate the chances of any bacterial proliferation. We also informed them about how our project is to design a rapid test kit for cereulide, and they also gave us some ideas on where we could implement it in society. For example, testing a packaged rice box before distributing the whole batch to the needy for consumption.

    Figure 8 Our teammates voulunteering with Food Angel

    Let's Yum Cha

    Cereunotes

    Key Questions

    1. How long has Suen Sifu (Master) been making Dim Sum? (Dim Sum is a traditional Chinese cuisine consisting of small steamed or fried savory dumplings with different fillings inside, e.g. shrimp dumplings)
    2. What motivates Suen Sifu to create high-quality Dim Sum?
    3. What is Suen Sifu's daily routine in preparing rice dishes?
    4. What is Suen Sifu's greatest concern in food safety related to rice dishes?
    5. If the Dim Sum is not sold out, would Suen Sifu reheat/store them to sell later?
    6. Would Suen Sifu be interested in using our rapid test kit to ensure food safety?

    Key Findings

    1. Suen Sifu has more than 30 years of experience in making Dim Sum.
    2. His passion for improving and evolving traditional cuisine motivates him to make better Dim Sum.
    3. Suen Sifu usually prepares the dishes early in the morning, lets the cooked rice cool in the bamboo boxes at room temperature, and reheats them to serve patrons upon ordering. This could be a hotbed for cereulide if the food is left in ambient temperatures for more than 3-4 hours.
    4. He is very careful not to make his patrons fall ill because of the dim sum he serves, so he keeps the environment as hygienic as possible to prevent contamination.
    5. Suen Sifu would not resell any leftovers. His predictions of sales are very accurate so the leftovers problem is not serious.

    Key Actions

    1. Understand the Chinese restaurants' operations through interviewing Suen Sifu and observing food preparation workflows.
    2. Create a Video Interview to let the general public learn about Suen Sifu and his commitment to serving the highest quality Dim Sum possible.

          Suen Sifu is a Chinese Dim Sum Restaurant Owner. We were delighted to have the opportunity to interview him at his restaurant in Jordan. With more than 30 years of experience as a Dim Sum Expert, he won the 2011 Best of the Best Culinary Awards - Winner of the High Honour Gold Award, Dessert Creativity Award, and the King of Shrimp Dumplings.

          We would like to know how his incredible skills in crafting dim sum and his careful maintenance of food safety have helped him pass on and innovate this unique Hong Kong culinary heritage. Suen Sifu is generally very supportive of our rapid test kit for cereulide. His years of experience in crafting the best quality dim sum also serves him very well, with appreciation from his customers and a good track record of food safety on his premises. Suen Sifu generously treated us to his best dim sums, including shrimp dumplings, deep fried turnip cake in thousand island sauce, red bean mice dessert etc.. He even let us take pictures around his kitchen, observing the work of the chefs. We are very grateful for his kind allowance for us to do this in-depth interview.

          Through observations in his kitchen, we found out that traditional Chinese restaurants often prepare food early, for example cooking the streamed rice in bamboo boxes, allowing them to cool in temperature, perhaps for 1-2 hours before reheating and serving the rice dish to patrons. This practice is kept due to the efficiency of serving the dishes, reheating is much faster than cooking from raw ingredients. However, we are worried if the steamed rice is stored in ambient temperatures for more than 3-4 hours and b. cereus spores are present, the spores would have sufficient time and chance to produce cereulide in the food served. If cereulide is produced, even reheating thoroughly cannot eliminate the toxins and the consumers would suffer from cereulide food poisoning. Apart from the practice of pre-cooking food for fast-serving, we found the cleanliness and other cooking procedures e.g. streaming of rice rolls very commendable and effective in maintaining food safety.

          Suen Sifu's generosity and passion in crafting and serving the best dim sums for his loyal patrons are very admirable. We sincerely hope that his Chinese restaurants can continue to prosper, his spirit and unparallelled techniques can be passed on through generations to preserve this beautiful Hong Kong heritage.

    Figure 9 Interviewing Suen Sifu, the owner of Let's Yum Cha