There are mainly three routes of cross contamination with allergens:
- Direct carry over: an allergen has contaminated the production line through earlier production, a second product on the same line “absorbs” the allergen. Good cleaing is the solution here, although this is often not easy and may require a long standstill of the line (economic cost).
- Indirect carry over: allergens from one product/production line are brought to another (free) product through the air (small powders, e.g.), clothing of employees, or through apparatus used on/for more than one line, or other…. Here a solution is stringent systems for QA and physical separation of employees, clothing and apparatus.
- Cross contamination through raw materials or ingredients: these can be cross contaminated themselves. The solution is good exchange of information between supplier and customer.
The control of cross contamination is often not easy and economically non-efficient. It is therefore very important that all parties take their responsibility in risk communication and agreed clear guidelines, so everyone knows and accepts the risks.