Study: Reheating Milk and Microbial Contamination

A research study from the University of Valencia (UV) was published by ScienceDaily on Jan. 29, 2010. Scientists examined 265 batches of milk and ready-to-use milk derivatives and checked whether their microbial quality fell into line with European Union regulations. It concluded that one-third of samples of milk and dairy products analysed in various restaurants and bars across Valencia (Spain) exceeded the microbe contamination limits set by the EU. Moreover, the samples were deemed unfit for human consumption.

Outcome of study

· 35% of the dairy products sampled exceeded the maximum contamination levels established by EU law for enterobacteriaceae

· 31% exceeded the limits set for mesophilic aerobic microorganisms

· 2% of the samples of hot milk (kept in jugs or stainless steel thermos ) tested positive for the bacteria Escherichia coli .

· Custards, mousses, puddings and crème caramels had the highest levels of contamination with microorganisms. This could possibly be due to the fact these are further processed after being heated.

· Greater contamination risk from milk kept in jugs.

· Reheating milk over and over again and pouring it back into a thermos, increases the risk of microbial contamination.

Tips

· When using milk it is important to clean jugs, thermos flasks and the steamers of coffee machines thoroughly and frequently. Use the right kind of hygienic sponges or cloths. Kitchen cloths are not suitable for disinfecting because of their microstructure, which means they transfer even greater levels of contamination.

· Containers with a lid are better, since tetrabricks opened with scissors are more exposed to microbial proliferation, and are especially vulnerable to enterobacteriaceae.

· Adding cinnamon to dairy products led to reduced microorganism

Click here to read the full article " One Third of Milk and Dairy Products Tested in Spanish Restaurants Exceed Accepted Microbe Contamination Limits" published by ScienceDaily (January 29 2010).

Source: Science Daily