Biogenic Amines in Fish and Fish Products
April - June 1997
Report prepared by Andrew Rigg
1.1 To determine the compliance of ish and fish products (including fresh, canned and dried) for histamine to the Australia New Zealand Food Authorities (ANZFA) Food Standards Code (the Code).
1.2 To determine the levels of two other biogenic amines, putrescine and cadaverine, which are also of public concern in these products.
Biogenic amines are volatile amines that are produced as a result of the breakdown of amino acids, typically on death of the animal. The most significant biogenic amine is histamine which is produced by the breakdown of the amino acid histidine. Other significant biogenic amines are putrescine which is produced by the breakdown of glutamine, and cadaverine produced by the breakdown of lysine (Rawles et al, 1996).
Histamine has been identified as the causative agent of the disease Scombrotoxicosis, or scombroid poisoning, which can, in severe cases, cause symptoms such as headache, nausea, vomiting, diarrhoea, itching, oral burning sensation, red rash and hypotension (Rawles et al, 1996). The disease was initially associated with the consumption of fish belonging to the Scombridae and Scomberosocidae species and hence the name Scombrotoxicosis.
The levels of biogenic amines in fish and crustacea can be used to indicate the degree of decomposition, so that the higher the concentration, the greater the amount of bacteria decomposition has occurred. Rawles et al (1996), states, at page 350, that,
- "[w]hile the presence of histamine in fish muscle is a good indication that decomposition has taken place, its occurrence is extremely variable. Its production is a function of time, temperature, and the type and level of microbial flora present. Variations within individual fish, depending upon the section of fish from which the meat sample originated, as well as variation between and within species have been reported".
This type of testing is the first for the Health Protection Service (the Service) and as such, comparisons can only be made to reports from other organisations. The standard does not specify a limit for crustacea or molluscs, however a number of these samples were determined for comparative purposes.
Standard D1, clause 1B(a), states that "[t]he level of histamine in a composite sample of fish or fish products, other than crustaceans and molluscs . . . must not exceed 100 mg/kg."
Standard D2, clause 5(a) states that "[t]he level of histamine in a composite sample of canned fish or canned fish products, other than canned crustaceans and canned molluscs . . . must not exceed 100 mg/kg."
There are no specific standards for cadaverine and putrescine. Although, the arbitrary maximum level of 100 mg/kg for both putrescine and cadaverine are used in this survey based upon the histamine standard.
For the purposes of this report, fresh fish is defined as fish that has not undergone any processing and processed fish products are those samples of fish which have undergone some processing, including smoking, canning, cooking and drying.
64 samples were obtained in the period November 1996 to April 1997. As shown in Figure 1, there was a variety of samples collected. Raw molluscs/shellfish included such things as prawns, oysters, scallops and whole mussels. Processed molluscs included cooked mussels. Other processed fish were such things as fish balls and a sample of fried fish meat. The other sample was seafood marinara.
Figure 2, shows the results for histamine. Of all the samples analysed, 91% (58/64) did not have detectable amounts of histamine, 8% (5/64) contained histamine at levels below the standard and 2% (1/64) failed to comply with the standard. This sample was dried fish imported from Asia and found to contain histamine at 653 mg/kg, more than six times the limit.
It was also found that 3.4% (1/29) of fresh fish compared to 14.3% (5/35) of processed fish samples were found to contain histamine, as shown in figures 3 & 4. These samples were one of fresh chunk tuna, one of tinned fish and four of dried fish.
Results for Putrescine and Cadaverine
Putrescine and cadaverine were detected in more samples as shown in Figure 5 & 6. Putrescine was found in 31% (20/64) and cadaverine in 44% (28/64) of the samples.
For putrescine, 34% (10/29) of fresh fish samples and 29% (10/35) of processed fish samples had detectable amounts. There were five samples that exceeded 100 mg/kg, which included two samples of green prawns, one sample of scallops and two samples of dried fish.
For cadaverine, 37% (13/35) of fresh fish samples and 43% (15/35) of processed fish samples had detectable amounts. There were three samples which exceeded a level of 100 mg/kg, these being two samples of dried fish and one sample of scallops.
Results for crustacea or molluscs
Of the twenty samples of crustacea or molluscs tested in the survey, histamine was not detected in any. 45% (9/20) had detectable amounts of putrescine and/or cadaverine with only three samples exceeding a combined level of 100 mg/kg. These samples were two of green prawns and one of scallops.
With only 2% of the samples analysed failing the requirements of the Code, there does not appear to be a significant problem with histamine levels in fish and fish products as a whole.
There is a significant difference of histamine levels between fresh fish and processed fish products. The comparative levels of 3.3% and 14.7%, respectively, indicate that processed fish products are more likely to contain histamine, especially dried fish products.
The number of samples containing detectable amounts of either putrescine or cadaverine is higher than for histamine. Using the arbitrary standard of 100 mg/kg for both putrescine and cadaverine (as based on the histamine standard), there are also more samples above this level than compared to histamine. No explanation for this is given, however it appears worthy of further investigation.
In regards to the standard, there is good compliance of fish and fish products with histamine levels. From the results, histamine is more likely to be detected in processed fish products, especially dried fish.
The significance of levels of cadaverine and putrescine found in these products has not been fully investigated and this issue may need addressing in the near future.
Another follow-up survey of processed fish products should be conducted within a three year period. The findings suggest that significant levels of concern of histamine are likely in fish, in particular samples that are fresh, tinned and dried. There appears little need to study further the levels of histamine in molluscs and crustacea as indicated by the results.
Australia New Zealand Food Authority, Food Standards Code, incorporating amendments up to and including amendment 32, December 1996.
Food Act 1992 (ACT), reprint as at 31 January 1996.
Rawles, D.D., Flick, G.J., & Martin, R.Y., Biogenic Amines in Fish and Shellfish, in Advances in Food & Nutrition Research, Vol. 39, p. 329365,1996.
This report could not have been possible without the excellent work of Fiona Wojtas for validating the method and analysing the samples.