IGEM:IMPERIAL/2007/Projects/Cell By Date
Cell by Date: Introduction
Imagine: You've had a really busy week, not kept up with your grocery shopping and all you have left in your fridge is some meat, some meat that's been there for a while...What should you do, Eat it and risk problems the next day? It looks bad, smells bad, but it's before its sell by date. If only there was a better way to tell if meat is good to eat.
Fresh meat is a highly perishable food product and unless appropriately actions are taken, e.g., packaged, transported and stored at refrigeration temperatures, can spoil in relatively short time. Factors affecting meat spoilage include intrinsic (e.g., pH, aw, composition, type, and extent of initial contamination) and extrinsic parameters (e.g., temperature and packaging atmosphere).
Among these, temperature is considered the most important factor. Although most countries have established regulations with maximum temperature limits for refrigeration storage, in practice these are often violated. Survey studies have shown that temperature conditions higher than 10°C are not unusual during transportation, retail storage, and consumer handling. Such temperature abuses during any stage of the chill chain may result in an unexpected loss of quality and a significant decrease of meat shelf life.
Surveys conducted also show that 1 in 3 consumers actually use food that is past the expiry date (this has been "verified" across the imperial igem team). Consumer ignorance, together with the lack of transparency in food processing and packaging are perhaps the two main factors for the 76,000 cases of food poisoning reported in the UK in 2006, many more presumingly under-reported.
Challenge tests are the conventional method used by the meat industry to evaluate a product’s shelf life. This is however valid only to the conditions that are tested in the lab, clearly impractical for a multitude of reasons. Although much initiative has been undertaken to minimize and predict real-world scenarios, e.g. stimuli sensitive materials, antimicrobial agents in food and intelligent cooling systems, sell-by date labels are seldom the best indicators of product shelf-life, and more importantly, the way that consumers handle their food.
The huge task at hand now is whether or not we can find an application in synthetic biology to solve this modern-day crisis - a better indicator to distinguish meat that is fit for consumption - rather than the often deceptive visual and olfactory examination, or the date that is written on your food labels that no one really reads.