Definition

A biohazard is defined as a biological agent, organism or substance, that poses a threat to human health. It includes bacteria, viruses, spores and toxins that impact negatively on human health.

This article focuses on biohazard management as a barrier to food poisoning, inadvertent exposure to allergens, and other threats which can lead to crew incapacitation.

Contributory Factors

Potential sources of a biohazard include food, water, needles, contaminated surfaces, and bodily substances (blood, faeces, vomit or droplets from coughing). The likely points of crew contact/origin are:

• Crew, ground staff or passenger who have contracted food poisoning e.g. travellers diarrhoea;
• Crew assisting passengers who are soiled with excreta;
• Crew performing resuscitation on passengers with no protection;
• Outbreaks of contagious disease in countries passengers are travelling from;
• Food contaminated with bacteria;
• Malfunctioning galley equipment resulting inadequately cooked or heated food;
• Soiled toilets and galleys;
• Poor maintenance of contaminated upholstery;
• Poor maintenance of ventilation and filtration systems; and
• Poor controls on water uplifts or toilet waste.

Control Measures Personal Hygiene

The single simple and most effective method of preventing infection is the practice of good personal hygiene. This will greatly limit the spread of infectious material. Simply washing hands will considerably reduce the risk of contamination from hand to mouth/nose, foodstuffs and other surfaces. It is recognised that due to aircraft design separate crew/food preparation washing facilities are not always available. The use of appropriate biocide wipes/gels as a substitute method for hand hygiene will assist in reducing possible cross-contamination.

Cabin Design and Service Design

The design of the aircraft cabin environment and the service operated within the cabin should, as far as reasonably practicable, reduce the potential for biohazards arising. Consideration should be given to the type of work surfaces particularly in food preparation areas both in terms of resistance to contamination and ease of cleaning. It is recognised that on some aircraft types, passengers leaving toilet facilities rejoin the cabin through the galley. This provides an ideal opportunity for cross contamination of surfaces as passengers move about the aircraft. Systems of work should be in place to mitigate this potential contamination.

Cleaning, Disinfection and Pest Control

Soiling of surfaces and equipment is unavoidable on aircraft. It is therefore essential that such residues are not allowed to accumulate to levels that expose crew members to risk of contamination or other materials such as food that will become the onward agent of infection. Operators should ensure that effective cleaning and disinfection systems are in place. These are the key to controlling biological contamination onboard aircraft. Effective cleaning and disinfection will remove microbiological hazards, however, unsatisfactory cleaning may result in the redistribution of contamination that may increase the risk. Cleaners working on aircraft need to be carefully monitored. It is not unknown for cleaners to clean the toilet floor and then the galley floor with the same equipment or use the same surface cloths in both toilet and galley (Chemical hazards from inappropriate use or storage of chemicals, and physical hazards from inappropriate or defective cleaning equipment may also occur.).

The reasons for cleaning:

• To remove matter on which biohazards would grow, thus reducing the risk of contamination and risk of infection from a surface;
• To disinfect specific equipment and surfaces to kill or prevent spread of microrganisms ;
• To remove materials that would encourage pest infestations
• To reduce the risk of foreign matter contamination;
• To remove dirt and grease and ensure a pleasant and safe working environment.

Airworthiness Considerations

Cleaning involves the application of energy to a surface, to remove dirt and grease. Energy is applied as:

• Physical, e.g. scrubbing;
• Heat, e.g. hot water; and
• Chemical, e.g. detergent.

Operators need to ensure that whichever of the three methods above they use that they understand the potential problems for commercial and civil aircraft:

• Abrasive scrubbing of aircraft components can lead to wear and premature change out of expensive aircraft parts;
• Hot water can, over wet areas, lead to corrosion under aircraft floors as well as potentially creeping into electrical systems; and
• Many detergents have to be very strong to be effective against certain hardy bacteria and spores and as a result they are not approved for aircraft use as they weaken interior plastics. This can lead to cleaning companies using weak and ineffective detergents.

The use of emerging technologies may assist in reducing these problems; there are new types of biocidal santiser coming onto the market that achieve a very high efficiency in destroying bacteria without using a very strong and aggressive detergent. Some have both Boeing and Airbus approvals and some even have a residual effect that continues to be effective for a number of weeks after application. Disinfection is the process of chemically reducing micro-organisms to a safe level that will not cause premature spoilage or infection. The aircraft manufacturer must approve any disinfectants used in the process.

Waste Management

Operators should have adequate arrangements onboard aircraft to deal with waste generated during flights. Waste should not be allowed to accumulate, be adequately contained and offloaded as soon as practicable. Operators should have adequate arrangements onboard aircraft to deal with potential pests that may take residence or accumulate in large numbers on board aircraft.

Pest Control

Several types of insect provide good disease vectors transferring infective material to food or surfaces. Flies and cockroaches present the greatest hazard because of their feeding habits and the sites that they visit. Flies often land on animal faeces where they pick up large numbers of infective material on their hairy bodies. In addition they defecate and vomit previous meals back onto the food as they feed. Cockroaches often live in sewers and commonly feed on infected waste. They hide in the most inaccessible places onboard aircraft and may transfer organisms from their legs and bodies to food and equipment as they move around aircraft. Operators should ensure that they have adequate pest control measures in place.

In flight disinsection may also be required to kill insects such as Mosquitoes.

Rodents are also common carriers of disease. They can excrete various harmful organisms including salmonella. Contamination may occur from droppings, urine, hairs and surface gnawing. Aircraft operators should ensure systems are in place both to identify possible infestation and provide suitable destruction methods.

Galley worktops on which rodents may have walked must be disinfected before use. Food suspected of being contaminated by rodents must be destroyed.

Food Preparation

Aircraft operators should ensure that the handling of food is conducted in a way to avoid contamination by harmful biological agents. Most aircraft food is catered on board pre-packed and ready to serve or to cook. Aircraft operators should have a separate programme for auditing the standards at the catering premises providing the food to ensure the food is free from biological hazards.

Where food is prepared on board, adequate food hygiene procedures should be in place to avoid potential cross contamination.

Aircraft operators should provide adequate training to ensure that crew members are aware of biohazards and the mechanisms in place to control them. Training should be carried out prior to the commencement of duties as a crew member. Training should be reinforced periodically.

Related Articles

• Pilot Incapacitation
• Food Poisoning
• Food Allergy
• Public Health and Aviation
• Coronavirus Disease 2019 (COVID-19)

Further Reading

• CAP 757: Occupational Health and Safety on-board Aircraft - Guidance on Good Practice, 2012.
• UK CAA CAP 1703: Aircrew guide to gastroenteritis, August 2018
• Health & Safety for Passengers and Crew, International Air Transport Association (IATA) website