Odours and Offensive Smells

As human beings our sense of an offensive smell has developed over evolutionary time scales to warn us of impending dangers. The majority of offensive smells are dangerous. Hydrogen sulphide often associated with "rotten eggs" is a sulphur compound also given off from sewers and other decomposing protein containing matter. Hydrogen sulphide gas is very poisonous and dangerous since the chemical can deaden the sense of smell very quickly. So sensitive is our sense of smell for gaseous sulphur compounds that they are added to natural and most fuel gases at the trace level to warn us of gas leaks. Many sulphur containing compounds are found in skunk sprays

Ammonia is familiar to most as the smell of window cleaner. Ammonia like compounds are also the basis of the offensive smell associated with rotten fish. Nitrogen and sulphur combine to form compounds characteristic of dead mammalian tissues that indicate putrification.

Fats and edible oils are susceptible to spoilage and are termed rancid when decomposition has begun. Noxious odours from rancidity are generated by aldehydes and volatile carboxylic acids.

Restorations of buildings after fires must be done with a great deal of care and attention to detail to ensure that styrene and aldehydes are removed or sealed from the interior atmosphere of the home. The heat and temperatures created in fires can create odours similar to those generated in the spoilage of edible oils and fats but only require minutes to do so rather than in the hours or days required for fatty oil spoilage.

Sulphur and Nitrogen containing compounds from sewers, municipal sludge conditioning ponds and livestock manure are some of the problem offensive odours that have been investigated.


Filth and Foreign Matter Food Contaminations

Problems with foodstuff contamination are not an infrequent occurrence. The problems have involved complaints of hairs in a home delivered fast food, the hairs were cotton fibers from a cloth. A complaint involved a wasp in a canned food imported from Asia, the wasp was Asian, which suggested that the contamination occurred at the processing factory.

Thumbtacks in store wrapped meats, punctured tinned foods in supermarket shelves, exploding juice, wine and beer bottles together with the discovery of maggots in a factory wrapped product are some problems we have been asked to investigate.