Hannah and I looked at some flour which had altered in appearance – it looked more clumpy. It had been around for some time. We wondered if it was still edible.
To compare, we looked initially at “good” (i.e. relatively new) white and wholemeal flour, and then compared images of the altered clumpy flour under the microscope.
Zeiss IM microscope, Bresser MikrOkular camera.
Andy and Hannah
White flour x4 objective 310817 – the following images show that good white flour is white/black/grey in colour with small amount of residual brown (residual wholemeal we assume not removed during cleaning process implemented to make flour white):
White flour x20 objective 310817:
Wholemeal flour x4 objective 310817 – the following photos show that wholemeal flour is very similar to white flour, except there is a lot more brown colour (wholemeal) in it – in both white and wholemeal flour circular carbohydrate areas are present in abundance and there is some clumpiness:
Wholemeal flour x20 objective 310817:
Altered white flour x20 objective. In the following photos, it becomes clear why the flour is altered in texture. Under a microscope the flour stands out from good white and wholemeal flour by having large amoutn green colouration in it (which immediately made us think that it was contaminated with fungal growth as this looked similar to our previous images of the green mold on bread). In addition, the clumps are significantly larger, as are the oval carbohydrate inclusions. The green fuzz appears to be located around the edge of the inclusions, suggesting fungal growth around the food source. We have been able to identify mycelia (fungal elements) confirming the diagnosis. We suspect that this is a form of penicillin – in any case no bacteria were seen, suggesting that the fungi are producing anti-bacterial substances which are killing off the bacteria. So, is the bread fit to eat? It could well be entirely fit to eat given its anti-bacterial properties but it does have fungal growth and we therefore recommended it was thrown away to be safe.
20x objective, showing mycelia:
Altered white flour x32 objective:
Altered white flour x40 objective: