“Shake, Rattle and Roll”: risk assessment and management for food safety during two Christchurch earthquakes

Lessons from the Field

Sally Johnstona

a New Zealand Ministry for Primary Industries (e-mail: Sally.Johnston@mpi.govt.nz).

To cite this article:

Johnston S. “Shake, Rattle and Roll”: risk assessment and management for food safety during two Christchurch earthquakes. Western Pacific Surveillance and Response Journal, 2012, 3(2):24-29. doi:10.5365/wpsar.2012.3.2.011

Abstract

Problem: Two earthquakes recently struck the Christchurch region. The 2010 earthquake in Canterbury was strong yet sustained less damage than the 2011 earthquake in Christchurch, which although not as strong, was more damaging and resulted in 185 deaths. Both required activation of a food safety response.

Context: The food safety response for both earthquakes was focused on reducing the risk of gastroenteritis by limiting the use of contaminated water and food, both in households and food businesses. Additional food safety risks were identified in the 2011 Christchurch earthquake due to the use of large-scale catering for rescue workers, volunteers and residents unable to return home.

Action: Using a risk assessment framework, the food safety response involved providing water and food safety advice, issuing a boil water notice for the region and initiating water testing on reticulation systems. Food businesses were contacted to ensure the necessary measures were being taken. Additional action during the 2011 Christchurch earthquake response included making contact with food businesses using checklists and principles developed in the first response and having regular contact with those providing catering for large numbers.

Outcome: In the 2010 earthquake in Canterbury, several cases of gastroenteritis were reported, although most resulted from person-to-person contact rather than contamination of food. There was a small increase in gastroenteritis cases following the 2011 Christchurch earthquake.

Discussion: The food safety response for both earthquakes was successful in meeting the goal of ensuring that foodborne illness did not put additional pressure on hospitals or affect search and rescue efforts.

Christchurch, New Zealand, is now best known to many people for the earthquakes that occurred in September 2010 and February 2011 – the latter killing 185 people. This article outlines some of the lessons learnt from the food safety response for each of the two earthquake events.

The 2010 Canterbury earthquake

Problem

The 2010 Canterbury earthquake was a 7.1 magnitude earthquake that struck at 04:35 on 4 September 2010. While the quake caused widespread damage and several power outages, there were low numbers of serious injuries and no fatalities – probably because the quake occurred during the night when most people were off the street. However, the damage was of such significance that the National Crisis Management Centre1 was activated and Civil Defence personnel in the relevant councils declared local states of emergency for Christchurch, the Selwyn District and the Waimakariri District (Figure 1). Power was disrupted in up to 75% of Christchurch, as well as many towns in the Canterbury region. Sewers were damaged and water lines were broken. A feature of the quake was significant soil liquefaction, which can cause buried pipes to float up to the surface. Some houses were damaged to the point that they were unsafe for residents. Welfare centres were set up in several locations, where more than 244 people slept on the night after the quake.

Figure 1. Districts for which a state of emergency was declared, 2010 Canterbury earthquake
Context

The risk assessment process in the 2010 earthquake response involved a range of food safety experts gathering in Wellington to discuss likely effects of the earthquake for consumers and food businesses. The discussions included identifying regulatory requirements unable to be met in the affected areas and the effects of damage and possible consequences on food safety (risks). Assumptions about levels and effects of damages were tested with field staff in the Canterbury region. Potential risks were prioritized and risk management options identified. Risk assessors and risk managers worked collaboratively in identifying risks, assessing likely impacts and deciding which risk management options to apply.

The primary food safety risks included:

    1. The use of contaminated water in food preparation and processing. There was a high likelihood that the earthquake and resulting liquefaction had damaged the water reticulation system through damage to buried pipes, which may have allowed sewage to contaminate the residential water supply.

    2. The use of contaminated foods due to property damage, unsafe water supplies and storage outside safe temperatures (due to power cuts).
Action

Water testing for indicators of faecal contamination (e.g. Escherichia coli) on reticulation systems was initiated immediately.

Key actions aimed at the public included:

    1. Providing water safety advice regarding water used for drinking and general hygiene (e.g. brushing teeth, handwashing);

    2. Issuing a boil water notice for the region; and

    3. Issuing food safety advice, including management of food in refrigerators and freezers in areas without power.

The key action aimed at food businesses was:

Having food safety officers and auditors circulate throughout the region to ensure food businesses were taking the necessary measures. This included:

    1. Ensuring that such businesses were able to render water for safe use with food. Many of these businesses use substantial amounts of water in processing and were keen to re-open as soon as possible.

    2. Conducting assessments for those businesses that had sustained moderate damage to ensure food had not become contaminated with physical hazards and that subsequent manufacturing of food would be protected from contamination by physical, chemical and microbiological hazards.

    3. Suspending the issuing of export certificates for export food businesses until adequate food safety measures were implemented and were effective.
Outcome

The February 2011 Christchurch earthquake

Problem

The February 2011 Christchurch earthquake, although smaller in magnitude than the 2010 earthquake, was more damaging and deadly for several reasons. The epicentre was closer to Christchurch, and shallower. The earthquake occurred during lunchtime on a weekday when the Central Business District (CBD) was busy and many buildings were already weakened from the previous quake and ongoing aftershocks. Liquefaction was significantly greater than that of the 2010 earthquake, causing significant ground movement, undermining many foundations and destroying infrastructures. Although communication was initially difficult, and it took many hours for a full picture of the devastation to be obtained, a full emergency management structure was in place within two hours, with national coordination again operated from the National Crisis Management Centre. On 23 February, the Minister of Civil Defence declared the situation a state of national emergency, the country’s first for a civil defence emergency.

Context

In this response, risk assessment (using processes as for the 2010 earthquake) identified several risks for food safety and security, including:

Action

The key actions for this response were similar to the 2010 earthquake with respect to issuing water and food safety advice, issuing a boil water notice for the region and initiating water testing on reticulation systems. Some changes and additions to this included:

Outcome

The national Food Safety response to the earthquake lasted less than three weeks. During this time, all of the approximately 2400 food businesses in Christchurch were visited (except the 500 odd in the red zone – cordoned-off CBD areas [Figure 2]), hundreds of enquiries were answered and plans were made for actions to be undertaken as closed food businesses re-opened. The local council and food safety officers resumed business-as-usual food safety management in the region from Monday 14 March 2011. Specific outcomes included:

Figure 2. Christchurch area map showing approximate red zone area, 2011 Christchurch earthquake*

* Reproduced with permissions from Canterbury Earthquake Recovery Authority.

Figure 3. Number of Enteric notifications from 22 February to 7 March, Canterbury, 2011 and 2008–2010 average7

Discussion

Food safety is not always immediately recognized as an important factor in response to natural disasters. People tend to focus initially on treating the injured, looking for survivors and repairing damage (e.g. restoring power, water supplies, opening transport routes). But in the background, food safety professionals are working hard, often from the minute of hearing about a natural disaster, to ensure that, among other things, hospitals are not put under further pressure with increasing numbers of cases of foodborne illness.

There were significant lessons learnt from the food safety response to both earthquakes in Christchurch. The response to the February 2011 Christchurch earthquake was both helped and hindered by the experience of the 2010 Canterbury earthquake. It was helped because all response agencies had learnt valuable lessons from the first event. It was hindered because many Christchurch residents had an expectation that water would be safe (because it had proven safe in the first event). This reinforces the view that while response preparedness is important, it is also important to be flexible and adapt to the specific needs of each response (no matter how similar, no two events are the same).

As there were only small numbers of gastroenteritis cases reported after each earthquake, we consider that the food safety response for both the 2010 Canterbury earthquake and the 2011 Christchurch earthquake was successful in meeting the goal of ensuring that foodborne illness did not put additional pressure on hospitals or affect search and rescue and earthquake recovery efforts.

Conflicts of interest

None declared.

Funding

None.

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