Food safety / by Fritz Käferstein and Jacqueline Sims

Food Saletv a worldwide public health 1ssue by Fritz Kaferstein and Jacqueline Sims espite great advances in mod- ern technology, keeping food safe remains a worldwide pub- lic health problem in both develop- ing and developed countries. Illness caused by contaminated food is a leading cause of suffering and death in the developing world , and affects millions in all countries. While few precise figures are known, due to inadequate or non- existent reporting systems in many countries, WHO estimates that only a tiny proportion of food-borne dis- ease is currently recognised, and an even smaller fraction reported, throughout the world. In develop- ing countries, the ratio between real and reported cases may be as high as 100: 1, while in industrialised countries the food-related health problems reported probably repre- sent much less than 10 per cent of the actual total. It is not surprising, therefore, that the impact on health of food-borne disease due to con- tamination of the food supply has not been well recognised by govern- ments , and the efforts of inter- national organizations to alleviate the situation have not proved very effective. In developing countries, diar- rhoea! diseases are of paramount importance. It is estimated that in 1980 alone, more than 1,000 mil- lion cases of acute diarrhoea occur- red in children under the age of five (excluding China), and five million of those children died. While there are several avenues of transmission of diarrhoea, until recently water has been thought to be the main vehicle involved; however, it is now recognised by the scientific com- munity that contaminated food is also an important source of enteric pathogens and diarrhoeas. Hence it is vital that wider recognition be given at national public health levels to the negative health impact of food-borne disease. Nowadays, there is constant movement of millions of people Mishandling at some stage in the food chain is responsible for most outbreaks of food-borne illness. Photo L. Sirman © around the world as immigrants, refugees or tourists. This greatly facilitates the spread and transmis- sion of enteric pathogens and , to- gether with considerable social , economic and cultural changes dur- ing recent years , has led to signifi- cant alteration of food habits; all these are factors linked with food contamination and resulting food- borne illness. Increased environ- mental pollution is a further ele- ment in the creation of new trans- mission cycles and the build-up of microbial concentrations , which in turn contribute to a greater contamination of certain foods and feed. Data from industrialised coun- tries suggest that Salmonella is at present the most important causal agent of food-borne disease. Data on the occurrence of salmonellosis in man show a significant increase in numerous countries during the last 30 years , a period of explosive growth in the centralised produc- tion and processing of food of ani- mal origin. International trade in food and animal feed too has reached unprecedented levels, and all these changes have encouraged the transmission and spread of en- teric pathogens in food. Salmonellae are far from being the only biological agents of acute food-borne disease. Many other micro-organisms have long been known to cause this form of illness (Staphylococcus aureus and certain strains of Escherichia coli, to name but two). And several "new " food- borne organisms, such as Campy- lobacter and possibly Listeria and Cryptosporidium, are now emerg- ing to claim the attention and con- cern of public health officials all over the world . In addition , there is the problem of food (mainly meat) infected by certain parasites such as Toxoplasma gondi, Trichinella spiralis and Taenia sp. , which can lead to both acute and chronic illness . No list of biological agents of food-borne disease would be com- plete without a reference to my- cotoxins and marine biotoxins. There are at least 150 different types of mould which, if growing in Articles and photographs that appear in World Health may be freely reproduced or reprinted without need for prior permission from the editor. The only exceptions are items marked with the copyright sign C. We only ask that due credit be given to World Health as the source. W oRLD HEALTH, March 1987 3 Food Safety Canning shellfish in Siberia. In the last three decades, there has been an explo- sive growth in the production and pro- cessing of food of animal origin. Photo L. Sirman © foods under suitable conditions, produce substances known as my- cotoxins which are toxic to man and animals. The foods in which myco- toxins are found are mainly protein- rich varieties based on peanuts, cottonseed , soya, and other plant sources that are vital to alleviate malnutrition due to protein defi- ciency. They are also frequently found in corn and rice. Some of 4 these mycotoxins have been shown to be powerful carcinogenic agents in animals , and may have the same effect on man. Others cause ergot- ism, alimentary toxic aleukia and other diseases . That toxins from certain fish and shellfish can be poisonous and cause death when eaten has been known since ancient times. But only within the last decades has the na- ture and biological basis for these food-borne intoxications been elucidated. Our knowledge of the extent of ill-health caused by marine biotoxins in many parts of the world remains grossly inadequate. In contrast to the quantity of alarming data about health hazards caused by biological contamination of the food supply is the paucity of recorded cases of ill-health associ- ated with chemicals in food . Of course, the illegal use of chemicals in food does not only mask quality, disguise deterioration or constitute a deliberate adulteration; it is also potentially very harmful to health. The suffering of some 20,000 peo- ple who had consumed adulterated cooking oil in Spain in 1981-82, and of whom as many as 350 died, is a sad and significant example. On the other hand, the legal use of food additives and the use of approved chemicals in good agricul- tural practice · (including animal breeding) does not seem to cause health problems. This issue was re- viewed by a joint FAO/WHO Expert Committee on Food Safety in 1983, which found that there was no evidence of harm resulting to hu- mans when chemicals are properly used and when the limits estab- lished by the Food and Agriculture Organization and WHO are not exceeded. Evidence of food-borne diseases induced by environmental chemi- cals such as heavy metals and polychlorinated biphenyls (PCBs) is also very rare. This may be due to large-scale under-reporting or to the great difficulty in correlating exposures with their possible latent effects. However , all the available data suggest that nearly all cases of food-borne disease are caused by biological agents, and that mishand- ling at some stage of the food chain is often responsible for the resulting illness. This finding frequently runs counter to the beliefs and fears of the vast majority of ordinary con- sumers, particularly in the indus- trialised world , as to just where the danger in our food supply may really lie. The question .now is whether the prominence tradition- ally given to the chemical safety of food really covers the whole range of food safety issues . On the basis of scientifically sound information available today it may be concluded that the most hazardous problems of food safety are at present, and will remain for the foreseeable future , those associated with the biological contamination of the food supply. • W oRLD HEALTH , March 1987