Street-vended foods (or street foods) are becoming an indispensable component of the food system in many cities of developing countries, increasingly emphasized by the rapid urbanization process, and significantly contribute to the food security of people who rely on their daily and widespread availability. Street foods represent, indeed, a regular source of income for million of sellers, local producers and processors, but also contribute to national economic growth: in Zambia street food sales have an annual turnover of US $100 million and employ around 16,000 people (mostly female with minimal education), and in Mexico generate around 12.7% of the Gross National Product and employ 28.5% of the national labour force. Due to their easy accessibility and diversified supply of meals, street foods also represent an inexpensive and accessible means for low income communities of meeting their basic nutritional needs: in Africa, for example, street alimentation enables 80% of urban populations to feed themselves easily and at lower prices and represents around 40% of the expenditure of their food budget. Despite the nutritional, social and economic benefits that may originate from it, the selling of street foods raises serious concerns for the health of urban population. The major concern is related to food safety, in particular due to biological agents and chemical substances in food products presented to the public. Over the years, the microbiological hazards have been deeply examined, though proper management and communication require further efforts; on the other hand, a lot still needs to be clarified about chemical/toxicological hazards and, in particular, on the measures that can be taken in order to prevent them or reduce the probability of their occurrence. A framework is needed for risk analysis of widespread products of street foods as meat, fish, cereals, nuts and water, in order to: identify the main chemical hazards; assess the likelihood of significant exposures under credible consumption patterns; characterize the toxicological risks for the general population. Starting from the intrinsic vulnerability of the mentioned food matrices to different chemicals, points of particular attention should be considered in order to produce recommendations addressed to the food vendors, thus protecting the healthy and social value of their goods. For instance: Area of vending. Since street food stalls are mainly placed in the most congested streets, close to manufacturing activities, bus/train stations, etc., foods and water are often exposed to several airborne chemicals, such as heavy metals, dioxins, polycyclic hydrocarbons and particulates. Selection of raw materials. Organic and inorganic pollutants, for instance, have different lipophilicity, thus implicating different accumulation patterns depending on the food composition. Storage. Inadequate temperature, time, moisture and storage facilities encourage the growth of mycotoxin producing fungi in numerous raw materials, mainly cereals, dry fruits, spices, coffee and cocoa. Food processing and cooking practices. Anti-nutritional factors in foods can be reduced by adequate processing and, consequently, bioavailability of nutrients will increase: e.g., the augmented bioavailability of iron and zinc and the digestibility of proteins in sorghum. The occurrence in foods of carcinogenic polycyclic aromatic hydrocarbons is strictly correlated to specific food processing, such as smoking, broiling, roasting and frying. Cooking tools. Inappropriate cookware, food containers and packaging and kitchen utensils used for and during the preparation, cooking, and serving, as well as the storage of food and raw materials, may determine the leaching of heavy metals and other chemicals in the food. Cleaning practices. The excessive or wrong use of insecticides and cleaning agents in the vending sites may determine the laying down of chemicals directly on the surface of the foodstuffs.
Numerous improper habits and practices carried out by the street food vendors can lead to toxicant exposures with long-term or transgenerational effects; however, these can be mitigated by the implementation of street food-targeted good practices. The quality of the street foods sector needs improvement in order to reduce the risks for food safety while maintaining the food security value.
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7th January 2011
PhD student in the “Food quality and Safety” area at the Italian Catholic University.