Spanish scientists have published a number of reports in English covering the safety of food dried outdoors, the effects of climate change on mycotoxins in food and the tuberculosis risk from raw milk cheese.
They were previously adopted by the Spanish Agency for Food Safety and Nutrition’s (AESAN) Scientific Committee.
For decades, plant and animal-based foods have been produced in Spain which are air-dried outdoors until reaching a low water activity (aw) that enables preservation at room temperature. Foods including raisins, dried apricots, dried figs, ñora peppers, and dried fish or octopus are at least partially air-dried.
They are spread over large areas outdoors either on the ground or in trays and left to dry until reaching dehydration levels so they remain stable during storage. Items are regularly turned to expose the different sides and to increase efficiency of the drying. Food is dried in a container with a transparent cover to protect it from rain, wind, dust, insects and animals.
Many pathogens are able to survive dry conditions for long periods. This is especially relevant for microorganisms that produce toxins, or which have low infectious doses. Biological hazards identified for dried fish products are Staphylococcus aureus and Clostridium botulinum while for fruits and dried vegetables they are Salmonella, Bacillus cereus and mycotoxins.
Experts said drying should be conducted in the shortest time possible, ensuring a decrease of water activity within the first two to three days of below 0.90 to inhibit development of aflatoxins, and drying should be continued until aw levels lower than 0.70 are reached, preventing growth of pathogenic microorganisms that cause spoilage.
Raw milk cheese and tuberculosis
Another opinion looked at the effectiveness of maturation for more than 60 days for cheese made with raw milk from herds where tuberculosis is detected.
Flexibility in European Union and Spanish rules allows the use of milk from herds that do not fulfill brucellosis and tuberculosis requirements. Cow’s milk may only be used after thermal treatment but other methods are available for milk from other animals. When it comes to brucellosis in sheep and goat herds, the milk can be used to manufacture cheeses with a minimum maturing period of 60 days.
The opinion covers cheeses produced with raw goat’s milk or from other species sensitive to tuberculosis except bovine and from females that do not have a positive reaction to tuberculosis tests or display symptoms but belong to a herd where it has been detected.
The Scientific Committee concluded prevalence of tuberculosis in Europe is low but raw milk and dairy products are among the top sources of contamination. Resistance of the different Mycobacterium types can be high with few differences between the species that produces the milk.
Research has shown survival of the causative agents of tuberculosis in cheeses for more than two months. So, it cannot be guaranteed that maturation for a period greater than 60 days is sufficient, said experts.
Climate change and mycotoxins
In the past two decades, there has been a growing trend in the prevalence of mycotoxins in foods with climate change cited as a contributing factor, said scientists.
Climate change can lead to increased temperatures, greater variability in weather conditions, rainfall patterns, droughts and storms.
Mycotoxin contamination is a problem in foods of plant origin, mainly cereals and nuts, but also in foods of animal origin such as milk, when the animal has been given contaminated feed.
A rise in the incidence of aflatoxins in corn and worsening of the already existing problem of fumonisins in this same crop can be expected, according to the reports.
Scientific evidence points to a geographical redistribution of the incidence of different mycotoxins, which may not necessarily represent an increase, due to the possible reduction in cultivable areas as a consequence of extreme weather conditions.
Mitigation strategies include preventive agricultural practices in the field; during the harvest and storage of cereals; physical, chemical and biological decontamination processes; and self-monitoring based on sampling and analysis in the different parts of the supply chain.