Food Surveillance News - Autumn 2008
In this Edition
Improper use of raw eggs linked to food poisoning
Acute gastrointestinal illness costs New Zealand five million working days each year
Research shows Australian exposure to PBDEs is low
Keeping an eye on food recalls
Implementation Sub Committee Coordinated Food Survey Workshop in Hobart
Improper use of raw eggs linked to food poisoning
Health authorities in New South Wales and Tasmania are investigating separate outbreaks of food poisoning which affected large numbers of people who ate foods containing raw eggs.
The New South Wales Food Authority (NSWFA) and NSW Health are investigating up to 49 cases of Salmonella poisoning while in Tasmania more than 150 people were affected in the Hobart area.
Tasmania’s Director of Public Health, Dr Roscoe Taylor, said 168 people have been interviewed in relation to the outbreak involving several catered functions and some restaurant patrons.
Of these, 79 have been identified as suffering from gastroenteritis symptoms, and 41 cases have been laboratory confirmed as being caused by Salmonella .
“The Public and Environmental Health Service is aware of at least eight patients who have been admitted to hospital over the course of the outbreak, most of whom have since been discharged,” Dr Taylor said on 7 February.
While the numbers could still grow as results return from laboratory testing, the outbreak was contained promptly and all cases dated back to exposures between the 23rd and 25th of January, he added.
“Salmonella has now been isolated from a Tartare sauce sample containing raw egg.”
Dr Taylor said public health evidence indicates that many raw foods carry an increased level of risk of Salmonella and other food borne infections, but such foods are often consumed as part of our normal eating habits.
On 15 February he announced new food safety measures designed to prevent further outbreaks of Salmonella gastroenteritis associated with the consumption of raw egg products.
Under the new requirements all food businesses choosing to make raw egg products must document the method of manufacture and follow strict and auditable procedures governing egg receipt, product preparation, storage and handling.
The shelf life of each batch of raw egg product will also be limited to no more than 24 hours under refrigeration, after which the product must be discarded.
Dr Taylor said the new egg safety measures will be legally enforceable by local government environmental health officers, as part food business licensing and inspection procedures.
In NSW the poisonings occurred in outbreaks in Wagga Wagga and the Sydney area in the six weeks leading up to Christmas. The NSWFA immediately issued a media release strongly advising against eating raw egg products.
Investigations revealed that all the cases involved reports of illness after people prepared and ate their foods at home, prompting the NSWFA to remind consumers about the safe preparation of raw egg products in the home.
NSWFA Director-General George Davey said eggs are a good, nutritious food and should be eaten as part of a balanced diet, but they do need to be handled properly.
“Eating foods containing raw egg products, like all raw foods from animals, presents a risk of food poisoning,” Mr Davey said.
The risk may be greater for those who are pregnant, older people or very young children and those with medical problems involving impaired immune systems, he added.
In the recent reported incidents, 11 people fell ill from eating Caesar salad containing a raw egg dressing or chocolate mousse also made with raw eggs, while three children were affected after drinking eggnog made with raw eggs.
The authorities suspect a further 35 people succumbed after eating homemade fried ice cream at a party in Wagga Wagga. The ice cream was prepared with a coating made from raw egg batter.
“Eggs can contain some bacteria on the outside of the shell that can easily transfer to the white and yolk when broken,” Mr Davey said.
“This is why we see foods like raw egg mayonnaise or mousse desserts implicated in Salmonella food poisoning. If these foods containing raw eggs are left out of the fridge for long periods, the Salmonella have a perfect environment to grow in.
'People should take care when preparing foods containing raw or undercooked eggs like homemade sauces or dressings such as mayonnaise, cake or biscuit batter, mousse, uncooked meringue, eggnog, eggflip or other drinks containing raw egg products.
“To enjoy eggs safely, make sure the shells are not cracked, broken or dirty and always store them in a refrigerator at 5 degrees C or below.
“If you choose to consume raw egg product make sure that you use it immediately after making, or refrigerate it.”
Also, use eggs within three to five weeks of buying them and always observe the ‘use by’ date on the container. Keep eggs away from other foods and always wash and dry your hands. After working with eggs, always clean surfaces, sinks, dishes and utensils thoroughly.
“Cooking eggs properly kills bacteria, but bacteria will survive in foods that are not cooked thoroughly. This is why you should be very careful if using raw eggs in food that will not be cooked,” Mr Davey said.
More information about buying, storing and using eggs is available in a fact sheet on the Authority’s website: www.foodauthority.nsw.gov.au/consumer/c-safe-use-of-eggs.asp
The NSWFA is the NSW government agency responsible for regulating food production and food safety throughout the state. The Authority is introducing a new Egg Food Safety Scheme which will ensure that eggs continue to be a safe food for NSW consumers.
Exposure to ethyl carbamate
Ethyl carbamate (EC) is a naturally occurring chemical found in foods that undergo fermentation during processing or storage. Foods such as bread, soy sauce and yoghurt, as well as alcoholic drinks like whisky, fruit brandies, beer and wine, contain quantifiable levels of EC¹.
This knowledge suggests that limiting the consumption of some foods and responsible drinking will reduce EC intake, which would appear advisable in the light of emerging international knowledge about the chemical.
In 2007, the International Agency for Research on Cancer reclassified EC from “possibly carcinogenic to humans” to “probably carcinogenic to humans ”.²
The carcinogenic potential of EC has prompted the introduction of international reduction methods to limit the level of human exposure to EC. Reduction methods have been successful, demonstrated in longitudinal studies conducted in the US (on a number of alcoholic drinks) and the UK (on whisky only) which show a marked decrease in the level of EC in alcoholic drinks and whisky respectively.³
In response to revised safety information Canada has also introduced maximum levels for ethyl carbamate in wines, distilled spirits, liqueurs and sake4. Furthermore, Health Canada has approved the use of genetically modified yeast in the production of fermented alcoholic beverages. Alcoholic beverages produced from modified yeast strains display a marked decrease in the level of EC (89%).5
In the light of this international experience FSANZ has continued to monitor the international regulation of EC. In 2007 the FSANZ Surveillance program conducted an analytical survey to measure the actual levels of EC in foods and alcoholic drinks in Australia. This was necessary to quantify levels of EC in the Australian food supply, to estimate dietary exposure more accurately and assess the potential risk to Australians’ health.
FSANZ designed and funded the survey and the analysis was conducted by the National Measurement Institute laboratory in Melbourne. FSANZ sought food samples in Queensland, Victoria and Western Australia to ensure it addressed possible regional variation in EC levels. FSANZ is grateful for the assistance of the Food Safety Policy and Regulation section in the Environmental Health Unit at Queensland Health and the Food Unit at the Environmental Health Directorate, Health Protection Group at the Department of Health, Western Australia, for their help in collecting food samples.
An overview of foods targeted and a summary of survey outcomes is outlined in Figure 1.
Figure 1: An overview of FSANZ analytical survey examining Ethyl Carbamate in fermented foods and alcoholic beverages.
The results of the analysis were very reassuring compared with the international experience. There were no detections in any of the foods tested except soy sauce, and very low levels found in just some of the alcoholic beverages. When compared to overseas studies, EC levels in Australia were lower than those reported in Danish and UK surveys. In Australia, EC levels were highest in sake, however this level was still lower than levels in the UK.
Given the absence of EC in the foods tested it was not necessary to construct a complex dietary intake model. However, a simple dietary exposure model for 95th percentile consumers was constructed for males and females aged 18+ years (derived from the 1995, National Nutrition Survey data). Soy sauce and all alcoholic beverages having quantifiable levels of EC were used in the model. From this model, estimated dietary exposures to EC for high consumers (95th percentile) of beverages and foods were calculated and used to determine the Margins of Exposure (MOE - the ratio of the Bench Mark Dose Limit to the estimated exposure dose). Exposure assessments for children were not considered necessary since the legal age for alcohol consumption in Australia is 18 years.
FSANZ created a second consumption model using as the basis the Australian Alcohol Guidelines (National Health and Medical Research Council (NH&MRC), 2001, Australian Alcohol Guidelines, health risks and benefits, available at: http://www.nhmrc.gov.au/publications/synopses/_files/ds9.pdf ). These national guidelines recommend an upper daily alcohol intake for the population to avoid long term health risks. The MOE based on the consumption set out in the guidelines was also calculated and compared with the MOEs based on 95th percentile consumption for both males and females aged 18 years and older (Figure 2 & 3). This comparison showed that when individuals are drinking alcohol within the recommended guidelines, the level of exposure to EC is lower than for the high (95th percentile) consumers.
This survey of foods and beverages consumed in Australia provides significant reassurance that EC is not present at quantifiable levels in all commonly available fermented foods surveyed, except soy sauce. It is also present in only some alcoholic drinks. The risk to health and safety for Australians from exposure to EC through consumption of food is therefore considered to be negligible. The risk to health and safety for Australians from exposure to EC through alcoholic drinks, other than sake, is negligible, even for high (95th percentile) consumers. High (95th percentile) consumers of alcoholic beverages would enhance their Margin of Exposure to EC if they modified their consumption to comply with the Australian Government Guidelines.
The full report of ‘Ethyl Carbamate in Australian foods; survey sampling and analysis conducted 2007’ is available here
Figure 2: Comparison of 95th percentile consumption MOE and calculated MOE based on Australian Alcohol consumption guidelines (NH&MRC, 2001) for men (18+ yrs)†
† MOEs were calculated based on either 95th percentile consumption data (NNS) or derived from the Australian Alcohol Guidelines (NH&MRC, 2001 available at http://www.nhmrc.gov.au/publications/synopses/_files/ds9.pdf )
Figure 3: Comparison of 95th percentile consumption MOE and calculated MOE based on Australian Alcohol consumption guidelines (NH&MRC, 2001) for women (18+ yrs)†
† MOEs were calculated based on either 95th percentile consumption data (NNS) or derived from the Australian Alcohol Guidelines (NH&MRC, 2001 available at http://www.nhmrc.gov.au/publications/synopses/_files/ds9.pdf
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¹(JECFA, 2005, Summary and Conclusions of the Sixty fourth report of the Joint FAO/WHO Expert Committee on Food Additives, pp 19-23 available at:http://www.who.int/ipcs/food/jecfa/summaries/en/summary_report_64_final.pdf).
²(International Agency for Research Cancer (IARC), 2007, Consumption of Alcoholic Beverages and Ethyl Carbamate (Urethane), Vol 96, available at: http://monographs.iarc.fr/ENG/Meetings/96-ethylcarbamate.pdf .).
³(US Food and Drug Administration, 1993, Urethane in Alcoholic Beverages Under Investigation. US Consumer, available at: http://vm.cfsan.fda.gov/~frf/fc0293ur.html
; Food Standards Agency UK, (2000), Survey of Ethyl Carbamate in Whisky, Food Surveillance Information Sheet Number 02/00, available at: http://www.food.gov.uk/science/surveillance/fsis2000/2whisky ).
4 (Health Canada, Canadian Standards ('Maximum Limits') for Various Chemical Contaminants in Foods, available at: http://hc-sc.gc.ca/fn-an/securit/chem-chim/contaminants-guidelines-directives_e.html#guidelines .
5 (Health Canada, Novel Food Information: Saccharomyces cerevisiae Yeast Strain ECMo01, available at: http://www.hc-sc.gc.ca/fn-an/gmf-agm/appro/nf-an148decdoc_e.html )
Acute gastrointestinal illness costs New Zealand five million working days each year
A major New Zealand Food Safety Authority (NZFSA) study, conducted for NZFSA by Environmental Science and Research, estimates that more than five million working days are lost each year in New Zealand due to gastrointestinal illness.
It also concludes that data from the notifiable disease reporting system may not be the most efficient way of providing risk management information for widespread illnesses such as diarrhoea and vomiting.
“The notification is not a good broad brush system and if we want to do something in more detail it is better to target resources for intensive work into one geographical area, such as we are now doing with campylobacter,” Dr Donald Campbell, NZFSA Principal Adviser (Public Health), told Food Surveillance News.
“There is no perfect system for notifiable disease reporting but the reporting system that we do use is good for showing us long term trends.”
The Acute Gastrointestinal Illness (AGI) study is a key part of the work NZFSA is doing to get an idea of the size of the problem of foodborne disease, Dr Campbell said.
“The year-long study helps us find where and how much self-reported AGI there is in New Zealand and what impact it has on those becoming ill. In addition, we were able to discover how many cases go unreported and why that might be.”
The study, which indicates that New Zealand’s rate of AGI of 7.8% is similar to other developed countries that have carried out similar studies, involved three parts covering the community, general practitioners and medical laboratories.
“This is the first of its type in New Zealand. Previously we have had to rely on estimates. The problem is obvious – few people who get diarrhoea or vomiting go to the doctor and, of those that do, the cause of infection is not always identified because many gastrointestinal illnesses take days or even weeks to cause symptoms.
“This means that there is a ‘pyramid of reporting’. This study found 219 AGI cases among the 3457 people surveyed. Of those, just 38 (22%) visited a GP with 19 stool samples requested (9%) and 17 (8%) submitted. Of these, three (2%) tested positive and only one was reported to the notification system.”
Dr Campbell said it is only by finding an accurate estimate of the causes of AGI in New Zealand that health protection resources, including food safety and promotion, can be targeted to areas that will best reduce levels of these illnesses.
“The more accurate the data we have, the better we can develop ways of combating foodborne gastrointestinal illness. We need to know not only how much there is, but also where it comes from. It’s like an iceberg – if the information that is being recorded is just a small fraction of the real situation we must find ways to estimate the true size of the problem.
“The alternative is to seek better ways of collecting more data. This study will be invaluable in both regards – it’s given us a better idea of how much AGI there really is and which groups of the population are getting sick, and given us indications of possible alternatives or additions to current data collection systems.”
Dr Campbell said there is further research to be done.
“While we now have a better idea of the extent of this problem in New Zealand, we still need certainty around the causes. We need improved estimates of the proportion of illness that is foodborne as opposed to person-to-person, contracted through unsafe water, animal contact and so on. Research will continue to improve the picture.”
Among the key findings of the study were:
- over the 12 month study period, the total estimated days of paid work lost due to AGI (both the sufferers and their carers) was about 5.2 million
- there are an estimated 6.5 million cases of vomiting and diarrhoea, and 4.6 million cases of Acute Gastrointestinal Illness in New Zealand every year
- cases were lowest in winter with 6.2% of people suffering AGI on any day, higher in spring (7.3%) and peaking in summer at one in every 10 (10.3%)
- although statistically not significant, more males than females (9.2 v 8.2%) reported an AGI (it is interesting that a recent Foodsafe Partnership survey on hand washing showed that women were significantly better than men at this simple infection control measure)
- as expected, children under five have a higher incidence of AGI than other age groups
- AGI prevalence is higher in Maori (11.0%) than non-Maori (8.0%)
- household size and income did not affect prevalence
- half of the people with AGI recovered by day two and 80% by day four
- 90% of people with AGI missed work or other activities, many for more than two days
- the criteria for severe AGI were met by 28% of the cases reported
- a third of people sought medical advice, with 22% getting advice from a GP (about 1.8 million cases a year seeking medical advice, and 1.0 million getting advice from a GP)
- about two-thirds of patients were either ‘good’ or ‘ very good’ in complying for requests for faecal samples
- the estimate that 0.5% of New Zealand cases of AGI are notified to national surveillance is slightly higher than estimates for Australia and Canada, but lower than for England.
By comparison, a March 2006 report for the Australian Department of Health and Ageing, conducted by Applied Economics, found the cost of foodborne AGI to be A$811 million a year, using 2002 hospital cost estimates. However, only 2.1 million work days are lost annually.
The research reports are available on the NZFSA website at: http://www.nzfsa.govt.nz/science/research-projects/index.htm
Research shows Australian exposure to PBDEs is low
For some time now scientists internationally have been concerned about the potential dangers that Polybrominated Diphenyl Ethers (PBDEs) pose to human health and the environment.
PBDEs (also known as persistent organic pollutants [POPs]) are a group of exclusively man made chemicals that are added to a wide variety of consumer and commercial products to improve their fire resistance properties. They are widely used in electronic goods such as computer and television housings, toasters, hair dryers, irons, foam bedding and furniture, carpets and textiles, car interiors, electrical wire and cable insulation and electrical connectors and sockets.
They are so functional their use has increased markedly over the last few decades and they have shown significant community benefits thanks to their property of slowing the spread of fire, which has led to a big reduction in the loss of human life and property.
However, PBDEs are now ubiquitous in the environment and this is what is causing concern. They are found from the Arctic to the Antarctic but their impact on the environment and human health is largely unknown. To date, PBDEs have been detected in sediments, marine mammals, fish, bird eggs and human milk, serum and adipose tissue (Darnerud et al, 2001). Overseas studies of foods have found PBDEs in dairy products, meat, fish, fish oils, shellfish, eggs, vegetables & vegetable oils (Bocio et al, 2003; Knutsen et al , 2005).
Their appearance in foods prompted FSANZ to take an interest. FSANZ monitors emerging issues as part of its surveillance program and in 2004 FSANZ commissioned an analytical survey of PBDEs in a range of foods supplied in Australia. As food is not the only potential source of exposure, FSANZ also coordinated its survey with a number of other relevant government agencies including the Commonwealth Department of the Environment and Water Resources (DEWR), the Department of Health and Ageing (DOHA) and the National Industrial Chemicals Notification and Assessment Scheme (NICNAS). DEWR also commissioned separate studies aimed at investigating levels of PBDEs in human blood serum and breast milk and aquatic sediment.
FSANZ analysed a total of 35 foods, including meat, dairy, oils and spreads, bread and bakery products and vegetables to cover as broad a spectrum of the diet as possible (Figure 1). Thirty of the 35 foods tested contained PBDEs. The highest levels of PBDEs were detected in boiled eggs, grilled pork chops, bacon and cream, with infant foods containing relatively low levels. Tap water, full fat milk, low fat milk, canola oil and iodised table salt had no detectable PBDEs.
Figure 1: An overview of FSANZ analytical survey examining PBDEs in foods.
The concentrations and types of PBDEs the survey detected in Australian food appear to be reasonably similar to those reported in other areas of the world. Australian breast milk has been found to contain PBDEs at levels below those reported for North America but higher than those in Europe and Japan.
Dietary exposure assessments were conducted for three month old breast fed infants, nine month old infants (receiving half of their energy requirements from either breast milk or infant formula, and half from solid foods), 2-5 year old males and females, 6-12 year old males and females, 13-18 year old males and females and males and females aged 19 years and above.
The assessments found the level of PBDEs in breast milk is very low (less than one part in a billion) and is expected to fall as use of these chemicals is phased out. PBDEs are also present in infant formula and other infant foods.
The assessments found dietary exposure of the general population to PBDEs in food was low. The main contributors to dietary exposure across the majority of the population groups assessed were bread, eggs, vegetables and meat, except for fully breast fed infants (Figure 2).
Figure 2: Major contributing foods to total estimated PBDE dietary exposure
To date there has been no reference health standard established for an acceptable intake of PBDEs. Evaluations conducted by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) concluded that for the majority of PBDEs studied, the available data from experimental animals or concentrations in human tissues was insufficient.
In the absence of sufficient data to establish a tolerable weekly or monthly intake for PBDEs, the margin of exposure (MOE) was used to determine the health risk of dietary PBDE exposure in different population groups. The No Observable Adverse Effect Limit of 0.1 mg/kg bw/day determined from rodent studies was the basis for MOE calculations. This approach concurs with the JECFA approach and conclusions.
The MOEs for the majority of the population groups assessed were around or above 10,000 (Figure 3). The population groups with comparatively high dietary exposures included three month old fully breast fed infants (MOE = 2000) and nine month old breast fed infants (MOE ~3000). However, as these dietary exposures were still more than 1,000-fold below any adverse effect dose observed in laboratory animals, they are unlikely to constitute a risk to infant health. Also, the significant benefits of breast feeding have been reported by many national health authorities and the World Health Organization.
Figure 3: Mean and 95th percentile MOEs for PBDE in various population groups
Note: MOE data presented is based on lower bound values; *no 95th percentile data available for 3 month breast fed infants.
On the basis of the available data and taking into account all the inherent uncertainties and limitations, FSANZ believes that dietary exposure to PBDEs in food is unlikely to be of public health and safety significance for Australians.
Given that National Industrial Chemicals Notification and Assessment Scheme has taken action against the more toxic PBDEs by implementing an interim suspension on the import and manufacture of penta-BDE and removing octa-BDE from the Australian Inventory of Chemical Substances, and their use is already being phased out internationally, it is reasonable to expect the low levels found in food to diminish in the future.
The full report of ‘Polybrominated diphenyl ethers (PBDE) in food in Australia; study of concentrations in foods in Australia including dietary exposure assessment and risk characterisation ’ is available on the FSANZ website at (http://www.foodstandards.gov.au/ ).
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References
Bocio, A., Llobett, J.M., Domingo, J.L., Corbella, J., Texido, A. and Casas, C. (2003) Polybrominated diphenyl ethers (PBDEs) in Foodstuffs: Human exposure through the diet.
Journal of Agricultural and Food Chemistry 51: 3191-3195.
Darnerud PO, Eriksen GS, Johannesson T, Larsen PB & Viluksela M. (2001). Polybrominated diphenyl ethers: occurrence, dietary exposure, and toxicology. Environ Health Perspect . 109 Suppl 1:49-68.
Harden F, Müller J & Toms L. (2005) Organochlorine Pesticides (OCPs) and Polybrominated Diphenyl Ethers (PBDEs) in the Australian Population: Levels in Human Milk , Environment Protection and Heritage Council of Australia and New Zealand.
JECFA (2006) Evaluation of certain food contaminants (Sixty-fourth report of the Joint FAO/WHO Expert Committee on Food Additives). WHO Technical Report Series, No. 930.
Knutsen, H. Bergsten, C. Thomsen, C., Sletta, A. Becher G., Alexander J. Meltzer, HM. (2005) Preliminary assessment of PBDE exposure from food in Norway paper presented at 25th International Symposium on Halogenated Environmental Organic Pollutants and Persistent Organic Pollutants (POPs) – DIOXIN 2005, Toronto Canada.
Keeping an eye on food recalls
Government agencies in Australia and New Zealand constantly monitor the food supply to ensure that it is safe, and that foods comply with standards for microbiological contaminants, pesticide residue limits and chemical contamination. Food that is identified as a risk to public health and safety is recalled. FSANZ is the coordinating agency for all food recalls in Australia.
Food manufacturers and consumers also do their bit by reporting foods that are unsafe, for whatever reason, to the local council or state/territory health department. Consumer complaints are often sent directly to the food manufacturer, and the manufacturer then liaises with the state/territory health department to determine if a recall is required.
The number of recalls varies from year to year depending on the foods available and the vigilance of food companies, food safety agencies and consumer complaints to identify food safety hazards.
In 1998, 1999 and 2000, for example, most recalls were made following consumer complaints. In 2001 and 2002, the majority of recalls originated from government testing, followed closely by recalls initiated by consumers. In 2003, the majority of recalls were due to government testing, followed by those initiated by manufacturers themselves, who do their own food safety testing.
In 2004 consumer complaints were again the main source of recalls. Consumer complaints accounted for half of all recalls, with two thirds of the recalls relating to labelling issues, including allergen labelling or the absence of it. Allergen labelling entered the Food Standards Code as a mandatory requirement in 2003.
While the number of recalls has fluctuated since FSANZ first collected data in 1990, there has been a gradual increase in the total number of recalls from 18 in 1990 to 68 in 2006, with the highest number (86) occurring in 2003.
Over the last seven years, the following trends have emerged:
- the percentage of recalls origina