Team:SDSZ China
TEST what you can't TASTE.
Background
Antibiotic injection is a common practice in dairy farms as a way to prevent mastitis in cow’s lactation period. But human’s long-term consumption of milk with excessive amount of antibiotics, can pose severe health threats.
In rural areas of China, milk goes directly to consumers without being tested for antibiotic residues, part of this is because currently used detection methods are either unreliable or not cost-effective enough to be accessed easily. Therefore we work to develop a cheap penicillin detection method, so that it can be used in relatively underdeveloped areas, and people in China could take one step closer to having an equal chance to qualified milk.
Human Practice
To gain a better understanding of how our project can help improve the situation of antibiotic residues in China, we interviewed Dr. Meng Lu from Chinese Academy of Agricultural Science for more information, and visited the plant of Sanyuan Milk Group, one of China’s largest dairy processing companies. We integrated our research and outreach to the optimization of our project, hoping to lessen the inequality between rural and urban residents’ access to qualified milk.
Project
1.0 We engineer our bacteria to generate Penicillin Binding Protein 5-Green Fluorescence Protein (PBP5-GFP), and bind penicillin to the coated wells. The protein is added to the sample, where the penicillin in the sample compete for PBP5-GFP with those on the plate, and the luminosity on the plate is measured and reflects its penicillin concentration.
2.0 PBP5 causes the hydrolysis of tripeptide Lys-Ala-Ala(KAA) when active and not bound with penicillin, releasing one alanine and exposing one amino group. We measure its hydrolysis by a) the electrical conductivity of the sample, and b) the amino group, which turns Kaiser blue.
3.0 To reduce the interference factors in milk and increase our project’s sensitivity, we used PBP5-CBD(Cellulose binding protein) to bind PBP5 onto a filter screen, through which the sample passes. All measurements are done on the filter screen.
