Sulphur Dioxide in Sausages and Other Products
July 1996 March 1997
Report prepared by Andrew Rigg
1.1 To determine the compliance of sausages, and other products, for sulphur dioxide to the Food Standards Code (the Code).
1.2 To determine the quality of sausages in this survey in comparison to surveys conducted in previous years.
1.3 To determine the compliance rate of other products, like dried fruit and manufactured meat, for sulphur dioxide levels.
Sulphur dioxide is a naturally occurring substance formed by the combustion of sulphur. In the food manufacturing industry it is used as a preservative, antioxidant, bleaching agent and as a vitamin C stabiliser. The food additive code number for sulphur dioxide is 220.
Sulphites are also widely used in the food manufacturing industry and are predominantly used as preservatives. All sulphites are considered dangerous to asthmatics and some can cause skin irritation to sensitive individuals. The food additive code numbers for the various sulphites are from 221 to 228.
In the laboratory, levels of sulphur dioxide and sulphites are measured as sulphur dioxide (as required by the Code) and as such, it does not identify the form or species which is present in the food.
The standard permissions for sulphur dioxide (and sulphites) are scattered throughout the Code. Standards for sulphur dioxide exist for a myriad of products from sausages to dehydrated peas, from gelatine to dried fruit and from fruit juices to alcoholic beverages.
This survey relates to standards pertaining to sausages, dried fruit, gelatine, dried vegetables and manufactured meats.
Standard C1, Part 10.47 states that "Sausage may contain not more than 500 mg/kg sulphur dioxide".
Standard N1, section (2b), states that "Preserved fruit may contain
(iv) sulphur dioxide
(A) in dried fruit, not more than 3 g/kg [or 3000 mg/kg];
(B) in crystallised pineapple, not more than 280 mg/kg;
(C) in preserved cherries, known as maraschino or cocktail cherries, not more than 300 mg/kg".
Standard I1, section (1b), states that "Gelatine
(i) may contain not more than 750 mg/kg of sulphur dioxide or sulphites calculated as sulphur dioxide".
Standard C1, Part 8.37 states that "Cooked manufactured meat may contain not more than 260 mg/kg of sulphur dioxide".
For dehydrated vegetables, the situation is slightly more complex. According to Standard F1(3a), only six different dehydrated vegetable products are permitted to contain sulphur dioxide as showed in the following table:
4.1 Samples Received
The laboratory received 173 samples of which the majority were sausages as shown in Figure 1.
4.2 Sausage Results
The laboratory received 103 samples of sausages from butchers and supermarkets located in the ACT. As shown in Figure 2, 39% of the samples failed the maximum permitted concentration (MPC) of sulphur dioxide of 500 mg/kg.
Figure 3 shows the distribution of results. Of the samples that failed, some were well above the permitted concentration for sulphur dioxide, with one sample having almost eight times the limit at 3700 mg/kg.
4.3 Dried Fruit Results
The laboratory received 61 samples of dried fruit from supermarkets, green grocers and health food stores. Figure 4 shows the numbers from various categories.
The category of berries includes sultanas, currants and raisins. Pome fruits are those produced on trees or shrubs, for example, apples and pears. Stone fruits are those fruits produced on trees belonging to the Prunus family, for example, apricots, peaches, plums (prunes), cherries and nectarines.
As shown in Figure 5, none of the samples failed the MPC of 3000 mg/kg for sulphur dioxide. The higher levels of sulphur dioxide were found in the dried stone fruits, such as apricots and peaches.
4.4 Other Product Results
There were three other types of products tested during the course of the survey which comprised of eight samples. They included manufactured meats, gelatine and dehydrated vegetables.
There were two samples of manufactured meats analysed and neither contained sulphur dioxide. Cooked manufactured meats may contain sulphur dioxide with a MPC of 260 mg/kg.
There were two gelatine samples analysed. One sample contained sulphur dioxide at a concentration of 370 mg/kg, whilst the other sample did not contain sulphur dioxide. The MPC of sulphur dioxide in gelatine is 750 mg/kg.
There were four samples of dehydrated vegetables were also analysed. These four samples were peas, beans, peas & carrots and vegetable noodles. Of these products, none failed their respective MPCs with the highest recorded level being in dried peas at 690 mg/kg.
From the results obtained, 39% of the sausage samples analysed failed to comply with the MPC of 500 mg/kg. As some of the samples yielded results many times higher that the MPC, there is cause for concern that some consumers, particularly those that are asthmatics, may be at risk of health problems. "Sulphites [or its associated sulphur dioxide] has been associated with triggering asthma attacks and acute allergenic responses , some of which are life threatening or fatal in a small number of susceptible asthmatic humans" (Sofos, J.N.).
A similar survey conducted in 1995 found that 27% of samples failed the MPC for sulphur dioxide in sausages, whilst in 1993 only 12% failed.
Given that the failure rate in the present survey is 39%, it would appear that the general level of compliance has tended to decrease. It is however, not easy to compare these results as previous surveys were conducted differently. In the present survey, all samples were purchased anonymously by laboratory staff with no indication given to retailers that sampling was occurring. In the previous surveys, however, the sampling was done by Environmental Health Officers who clearly identified themselves at the time of sampling.
5.2 Dried Fruit
There does not seem to be a problem with sulphur dioxide concentrations in dried fruit, however, some of the samples do come close to exceeding the limit of 3000 mg/kg. Overall, these manufacturers should be congratulated on their efforts for keeping the levels below the MPC for dried fruit.
5.3 Other Products
Of the few samples tested, there appears to be good compliance to the appropriate sulphur dioxide MPCs.
Compliance of sausages to the FSC is clearly poor with 39% of the sausages failing the MPC of 500 mg/kg.
Compliance of dried fruit and other types of products tested is excellent with none failing their respective MPCs.
In relation to the poor compliance of the sausage samples, the Service aims to undertake statutory sampling by Environmental Health Officers in the near future, especially from retailers who produced unacceptable results in the past. Failure to comply with the Food Act 1992 (ACT) may result in prosecution as per the Act.
Dried fruit products need not be resurveyed for some time as there was good compliance.
Surveying other food types for compliance to sulphur dioxide MPCs should be conducted.
Hanssen, Additive Code Breaker, Commonwealth Department of Health, Lothian Publishing Co., Sydney, 1984.
Food Act 1992 (ACT), reprint as at 31 January 1996.
Sofos, J.N., Antimicrobial Agents, in: J.A. Maga and A.T. Tu (eds.), Food Additive Toxicology, Marcel Dekker Inc., New York, 1994, pp.514517.
Australia and New Zealand Food Authority, Food Standards Code, incorporating amendments up to and including Amendment 32, December 1996.