When it comes to the different types of milk containers, you might think that the only reasons to choose one over the other would be factors like convenience. Recent research, however, suggests that container material type can actually affect milk's flavor.
For the North Carolina State University study, samples of pasteurized whole and skim milk were stored in six half-pint (237-ml) containers in total darkness at a temperature of 39 ºF (4 ºC). For each of the two types of milk, the containers consisted of a paperboard carton, a plastic bag, three plastic jugs (all made of different types of plastic) and a glass bottle – the latter served as a control.
A panel of trained taste-testers assessed the flavor of the samples on the first day of the testing period, then again after five, 10 and 15 days had passed. At those same intervals, the scientists analyzed the samples to see if compounds from any of the packaging materials were making their way into the milk. Additionally, a blind consumer taste taste was performed at the 10-day mark.
When all was said and done, it was found that the paperboard cartons performed the worst.
This was due not only to the transfer of paperboard flavor into the milk, but also to the paperboard's absorption of the milk's flavor. The taste-testers noted distinct off-flavors, plus gas chromatography/mass spectrometry analysis showed that paperboard compounds were present in the milk. It was also noted that skim milk fared worse than whole milk.
By contrast, the milk in the three types of plastic jugs was found to be considerably fresher-tasting, on par with the milk in the glass bottle. Milk stored in the plastic bags wasn't quite as good, although still better than that in the paperboard cartons.
The scientists note that the relatively poor performance of the cartons is an important consideration where children are concerned, as school lunch programs in the US typically serve milk in such containers.
"Milk is more susceptible to packaging-related off-flavors than many other beverages because of its mild, delicate taste," concluded the lead scientist, Prof. MaryAnne Drake. "Milk’s taste can be impacted by the exchange of the packaging’s compounds into the milk and by the packaging absorbing food flavors and aromas from the surrounding refrigeration environment."
The research is described in a paper that was recently published in the Journal of Dairy Science.
Source: Elsevier
