Potassium Bromate (E924): It is often added to bread as a flour improver; to strengthen the dough, make it rise better and give it a uniform consistency. On cooking and heating, it breaks down into bromide which when consumed in excess can inhibit the metabolism of the iodine enzyme. It is regarded as a possible carcinogenic by International Agency for Research on Cancer (IARC) and is banned in certain countries like Argentina, Brazil, Peru, Canada, Nigeria and South Korea. On the label, it may sometimes show up as 'enriched flour'.
Sodium Nitrate: This preservative is mostly used to cure processed meat such as bacon, ham and sausages. It is this additive that preserves the pink colour of meats and prevents botulism. The United States Environmental Protection Agency has found that high concentrations of nitrates can affect the circulation of oxygen in the body.
Diacetyl: Diacetyl is added to impart the buttery flavour and aroma to microwave popcorn. It is also the name of a naturally occurring compound found in butter, beer and other fermented foods. In most cases, it is produced artificially to provide a last longing buttery flavour and delay rancidity in packaged popcorn. The problem with microwaving popcorn is that on heating the diacetyl in the bag vaporizes. When this buttery steam is inhaled it can directly reach the lungs and cause lung disease.There have been dozens of cases where workers have developed a lung disease called bronchiolitis obliterans, also known as “popcorn workers lung,” and other respiratory illnesses from exposure to the vapors of diacetyl while working at popcorn manufacturing units.
BHA and BHT: These are two preservatives that are most commonly used. Butylated hydroxyanisole is a synthetic antioxidant that is used to prevent fats in foods from going rancid. Butylated hydroxytoluene stabilizes fats and is used to retain the smell, color and flavor. Some authorities regard these to be possible carcinogenic but this has mostly been based on animal studies. Cereals and other foods with fat like potato chips, chewing gum, vegetable oil and shortening may contain these preservatives.
Sulpur Dioxide: It is often used to prevent discolouration and growth of bacteria in dried fruits and jaggery. It is also know to prevent brown spots and keep raw fruits and vegetables fresh. Sulphur dioxide bleaches out rot and in process it may also destroy the essential Vitamin B and Vitamin E. If you are asthmatic it may trigger breathing problems.