Chemical risk in food industry
The strict requirements of the food industry in terms of hygiene have as a direct consequence the existence of a major chemical risk. Indeed, except some manufacturing processes which require the use of various chemical products such as separation techniques widely used in this industrial sector (extraction, deionisation, solubilisation,…), cleaning operations constitute the first source of risk.
The maintenance crews are specifically exposed as well as the maintenance workers who are often victims of accidents while checking valves or pipes (leak, bursting). The safety of the consumers is ensured by the regular cleaning and disinfection of the installations. As well as the processes of treatment of raw materials (especially during skimming operations in dairy processing plants where caustic soda and acid splashes on the hands are frequent), the cleaning operations particularly requires the use of very diversified chemical agents.
At the beginning, three specific products were mainly used
- the chlorinated alkalines such as sodium hypochlorite (bleach)
- soda (in very large quantities)
- and nitric acid.
Many other products can be encountered today like peracetic acid or hydrogen peroxide.
Formol is especially used in the poultry industry for the environmental disinfection by fumigation. This product, classified as carcinogenic, causes an important embarrassment for the people who arrive on the working place following the disinfection. It is thus more and more replaced by glutaraldehyde, whose potential chronic toxicity has not been detected until today.
Other products can also be quoted, such as sulphuric acid (little used) or ammonia (as cooler in the meat industry for example). Foam guns, prepared with a solution of chlorinated alkaline (like sodium hypochlorite) mixed with other additives (foaming products) are massively used for the washing of walls in slaughtering chains but are also met in the majority of industries of this sector (frequent operation, often daily and at least weekly). They are presented under the form of a small tank containing the solution, connected to a pipe, and allow to deliver a thick foam under a pressure ranging between 3 and 4 bars.
Following the first washing, walls are first rinsed with water, then with nitric acid or peracetic acid before a last disinfection with glutaraldehyde or peracetic acid. The areas which cannot be reached by the jet must be cleaned with a sponge, which increases the risk of exposure.
It is frequent to see operators increasing the amount of recommended product, thus modifying the concentration of the solution which then becomes corrosive. Even if the staff is equipped according to the risk associated with these operations, the face can be exposed as well as the other parts of the body when clothing is removed.
Moreover, the frequent use of rainproof suits not adapted to the chemical protection and thus non resistant to the products used can induce severe chemical accidents
The maintenance operations such as the stainless weldings are related to a specific risk. The passivation pastes containing hydrofluoric acid (HF) are systematically used, thus involving a requirement of HEXAFLUORINE® solution. HF solutions can also be used during other operations dealing with the cleaning of all the stainless equipments. Lastly, the risk due to the use of HF is met during the preparation of mixtures with nitric acid and fluoride salts (such as sodium bifluoride NaHF2 for example).
These industries have water treatment stations in which the presence of lime, sulphuric acid or even soda is systematically detected. Finally, some R&D or analysis laboratories in which the chemical risk is known and well identified are quite often found in these plants.