I like these containers. I am not using them for baby food. I am using these for storing things like purees and pesto. It's very convenient to freeze in these smaller size containers, then thaw one and use the contents for a few days from the fridge. Like most OXO products, they seem to be good quality. The lids fit well, dimensions seem accurate, etc. I don't find much use for the tray because I just have these stacked vertically in my freezer. I did try to verify the composition of the container, because for food items (especially those meant for babies), you want to ensure there are no unexpected contaminants. A more proper analysis would probably use FTIR, NMR or mass spec, but I don't have those instruments unfortunately. The only things I have are an XRF analyser and a raman spectrometer, both handheld units. I didn't detect any metals except for a very small amount of Zinc (about 0.15%) with the XRF analyzer (keep in mind it's a portable unit, so can probably only detect to the 50-100 ppm level or so). I also used my raman spectrometer to get a reading on the silicone container. The following is my interpretation of the results. However, keep in mind I am not a formally trained spectroscopy expert. If anyone reading this review is an expert, feel free to chime in with a comment about any errors I've made and I will correct them. My unit matched the spectrum to D5 siloxane. This is sometimes used as a precursor building block for silicone and silicone rubbers, but I believe it was a false match. The library on my spectrometer unit doesn't actually have a pure silicone, like PDMS, in it -- it seems to only have some of the other precursors like the D5 siloxane that was matched. Additionally, the raman spectrum for a silicone polymer like PDMS looks nearly indistinguishable from the D5 spectrum in my library. I believe this is because the D5 siloxane molecule is essentially a circularized version of 5 building blocks from a PDMS polymer. Due to the circularization, it does not have the methyl end groups that would show up in a short polymer chain spectrum, and thus appears to mimic the spectrum retrieved from long polymer chains. If you look at the raman spectrum for pure PDMS of various chain lengths (you can reference Figure 3 in Jayes et. al., Analytical Chemistry, 2003) you'll see the main difference between short and long chain polymers (in the range I can test, which is about 300 to 2800) is the ratio of the peaks at 709 and 1000 cm^-1. The spectrum I obtained closely resembled the long chain PDMS spectrums presented in that article. At some point in the future, I might put some oil or DMSO into one of these containers to see if anything leaches out, and will update this review if I find anything interesting. In summary, these containers work well and seem to be of a relatively pure material, but I don't have the full suite of instrumentation to do a complete analysis. Some of the main contaminants you might expect in silicone polymers are cyclosiloxanes and unreacted precursors. Those contaminants would be difficult to detect with my equipment, especially at low levels. However, other common chemicals that many people are aware of, such as BPA and phthalates, should be detected by my equipment and were not found in these containers.
