the first thing that came to mind was a yeast or fungus. How long do you leave the cooked soaked food down for?
Budgie Ailments and Diseases
http://talkbudgies.com/showthread.php?t=4109
--------------------------------------------------------------------------------
In general Budgies are healthy little creatures and most live their whole lives without suffering from any disease, but as with all livestock, they are subject to a number of ailments and,because they are such small creatures, they do not have a great deal of resistance to illnesses. Prompt attention is very important.
The first sign of trouble is often finding the budgie roosting on both feet with its head tucked under its wing.
Pet owners should be aware that it is normal for a budgie to perch on one foot with its head tucked under its wing.
If the plumage is fluffed out and the droppings are loose,watery or green and slimy, it is a sign that all may not be well. The budgie should be caught and examined for injury, if none is obvious then the budgie should be placed in a seperate cage away from other budgies, and placed near heat e.g ontop of a boiler, infront of a fire or anywhere where it is free from draught and fume free,gas appliances are not recommended, obviously ensuring you do not put the bird anywhere where they will be too hot. A dish of water needs to be placed near the cage to provide humidity. If the illness is only minor then this is most effective. If the droppings are loose and green, very often the condition can be cured by using strong cold tea instead of water, this is soothing if the alimentary system has been inflamed for any reason.
Anal prolapse ( egg binding) is another distressing condition from which breeding hens can suffer, this very seldom occurs if the seed you are using during the breeding is mixed with a very small amount of cod liver oil emulsion. This is usualy caused by the bird trying to pass a soft shelled egg or a large egg. Very rarely can it be the result of constipation. The symptons can be fluffed feathers,tail held high, swelling around the vent, which in severe cases part of the intestine may protrude from the vent.
CoccadiaThis is a parasite which lays eggs in the intestines and penetrates the mucous lining. The eggs, called oocysts are passed in the droppings and can be picked up and swallowed by another bird. They multiply in the gut and eventually produce more oocyts, because budgies eat their old droppings this makes the disease very infectious within your flock.
TrichomoniasisThis is a disease which is caused by vomiting, the vomiting is far more violent then regurgitating seed, and can cause feathers to be matted, this disease can be transmitted to other birds by beak to beak contact. An effective treatment is the antibiotic soluble emtryl, at the rate of one level teaspoon per 3.8 litres. The solution should not be kept longer than 3 days, excess dosage can be dangerous and the medicine should be taken for the full seven days to prevent a resistance being built up to the antibiotic.
CandidiasisThis usually occurs in the mouth or crop, mixed with dead tissue and partially blocks the birds organs, birds are usually treated with a fungal antibiotic but very often the diagnosis is not made till the infection has progressed to far for a cure to be effected.
AspergillusThis affects the air sacs and lungs of the bird, but if the bird is fit and vigorous then it will overcome the disease before it reaches dangerous proportions.
Also this site is very helpful regarding budgies' health and cures
http://www.officialbarrieshuttbudgeriga ... lments.htm