Storing Flour

Flour should be kept on a cool, dry, airy shelf in its bag or in an airtight container. Never mix new flour with old.


From time to time people find that their food cupboards have become infested with tiny grey or brown insects.  These are called psocids (pronounced so-sids) and are often found in the packaging of dry goods such as flour, powdered milk, sugar or semolina. 


They are not caused by poor hygiene, and are just as common in the cleanest of homes be they old or new.  They prefer to live in dark, warm, humid places – such as the folds of packaging in food cupboards. The kitchen environment is likely to provide the conditions they need and fitted cupboards provide the darkness that attracts them. Some food products, including flour, naturally contain moisture.  In warm conditions psocids can rapidly increase in number.  This is most likely to occur during the summer months when temperatures are higher, leading to their discovery in the autumn.

 

To prevent the manifestation of psocids in the kitchen:

• Packets of food that have been opened should be used up quickly and not pushed out of sight to the back of the cupboard.
• Food storage areas should be well ventilated and cool.  (Liposcelis bostrychophila, the psocid that is overwhelmingly the most common psocid pest in the domestic situation, likes warm humid conditions. Cold and dry situations are unfavourable for its survival.)
• If storage in cool ventilated cupboards is not possible, make sure that your cupboards are always free from condensation and damp.  If you notice that condensation occurs in your kitchen, particularly during cooking or washing, open your windows.  If the problem continues, it may be necessary to take additional precautions.  Advice on preventing condensation should be sought from the local Environmental Health Department.
• Any potential hiding places should be sealed with paint or mastic.  Many fitted kitchen cupboards are made from laminated chipboard and the surfaces, which are not on view, tend not to have a laminated finish.  These unfinished edges can provide crevices for the psocids to hide in and should be sealed with a coat of paint or varnish.
• Regular cleaning of cupboards is advisable, since crevices of cupboards harbouring dry food can also provide a food supply for psocids. Use of a vacuum cleaner is recommended, provided the contents are then immediately disposed of in an outside waste bin.  Do not use a very wet cloth since this may seal dry food into crevices, encourage humidity and the growth of mould in chipboard.


If these prevention measures fail and you do discover psocids in your food, do not use an insecticide because of the danger of contaminating your food.  Dispose of all visibly infested packages in an outside waste bin and thoroughly clean the cupboards using a vacuum cleaner paying particular attention to crevices.  If psocids are found in other parts of the house, clean the area with a vacuum cleaner.  Immediately after use, dispose of the cleaner contents in an outside waste bin.


It is important to make sure that when foodstuffs are replaced in cupboards that have been cleaned they do not reintroduce the psocids.  Containers and packaging may be treated by placing them in a deep freeze for 24 hours (enclosed in a plastic bag).  This will kill any eggs or juveniles that might be hidden in the folds of packaging.  Labels should be removed from tinned food, bottles and jars to ensure that no psocids are hiding behind the paper. Use a felt tipped pen to label the bare containers.  The freezer treatment is also suitable for books and other objects which you might suspect of harbouring eggs/ individuals (enclose them in plastic bags).