Poisoning by biogenic amine histamine arises from the consumption of food, particularly certain types of fish when it starts to decay. However, histamine can also occur as a result of fermentation during the manufacture of certain cheeses and sausages.
According to the European Food Safety Authority (EFSA), biogenic amines are thermostable and are not inactivated by heat treatment during food processing or by cooking at home.
Some of the highest histamine levels have been found in Swiss (American) cheese and the hard cheese Almkäse. Long maturation periods and the use of unpasteurised milk, acid curds, or starter cultures that contain certain microorganisms can produce higher histamine levels in cheeses.
Reduced salt and more bacterial growth
Food manufacturers are worried that efforts to reduce the salt content of cheese could lead to increased bacterial growth and increased histamine levels.
Incidents of illness involving histamine in cheese were first reported to the Food Standards Agency (FSA) in 2003. Between 2001 and 2007, there were two reported cases. However, provisional data in a paper presented to the last meeting of the FSA’s Advisory Committee on the Microbiological Safety of Food, indicated that between 2008 and 2015, there were 20 reported incidents.
The paper reported the increased numbers of cases of histamine poisoning “were largely mature cheddar cheeses”. Although the reason for this was unclear, the FSA suspected it reflected greater consumption of cheddar cheese rather than other cheeses in products such as lasagne and macaroni cheese by five-year-olds in nursery/ school settings. “The data suggests that children may be particularly sensitive to high levels of histamine,” said the paper.
Poor quality and storage
Higher amounts of amines are also found in foods as a consequence of the use of poor quality raw materials, microbial contamination, incorrect conditions during food processing and poor storage, it was reported.
Histamine formation in foods is also related to factors such as their pH, water activity, composition, microbiological composition, plus storage time and temperature. The optimum temperature for biogenic amine formation is reported by EFSA to be between 20°C and 37°C.
The histamine concentrations in some cheeses implicated in poisoning have been reported to range between 850 and 1,870mg/kg. The FSA said some of the larger cheesemakers and supermarkets had set rejection limits of 500mg/kg for histamine in cheese.
However, the FSA was particularly concerned that such controls were far less likely among smaller cheesemakers, because of the high costs of histamine testing.