Application of ozone for enhancing the microbiological safety and quality of foods: a review.

Aflatoxin in food and feed: occurrence, legislation and inactivation by physical methods

Molds are parasitic plants that are ubiquitous in livestock feedstuffs. Even though molds themselves reduce the quality of grains, their synthesis of chemical substances termed mycotoxins causes the greatest monetary loss to the animal industry. Five major mycotoxins that impair growth and reproductive efficiency in North America are aflatoxins, zearalenone, deoxynivalenol, ochratoxin, and ergot. Aflatoxins are produced by Aspergillus flavus and Aspergillus parasiticus. Consumption of grains containing aflatoxins by swine affects reproduction indirectly by reducing feed intake and growth. In swine, aflatoxins impair liver and kidney function, delay blood clotting, increase susceptibility to bruising, and interfere with cellular humoral immune systems. Ruminants are comparatively resistant to aflatoxicosis, but presence of aflatoxins in milk of dairy cows is closely monitored for human safety. Depending on environmental conditions, Fusarium roseum can produce either zearalenone or deoxynivalenol. Days 7 to 10 postmating seem to be a critical period of gestation for zearalenone to exert its detrimental actions on early embryonic development. Presence of deoxynivalenol in swine feedstuffs decreases feed intake, causes feed refusal, and induces occasional vomiting. Several species of Penicillium and Aspergillus produce ochratoxin, a mycotoxin that causes necrosis of kidney tissue. Ergot alkaloids produced by Claviceps purpurea on wheat can cause reproductive problems and are associated with lactational failure in swine. Various methods have been developed to remove mycotoxins from infected feedstuffs. Chemical analyses in laboratories as well as diagnostic kits suitable for use at the elevator or farm can be used successfully to identify which mycotoxins are present in suspect feedstuffs.

Mycotoxins and reproduction in domestic livestock.

Aflatoxins are secondary metabolites produced by species of Aspergilli, specifically Aspergillus flavus and Aspergillus parasiticus. These molds are ubiquitous in nature and grow on a variety of substrates, thereby producing aflatoxins. Aflatoxins are of great concern due to their biochemical and biological effects on living organisms. In this article, the occurrence of aflatoxins, their biosynthesis, factors influencing their production, their effects on living organisms, and methods of detection and control in food are reviewed. Future areas of research involving mathematical modeling of factors influencing aflatoxin production and alternative methods of control, such as modified atmosphere packaging, are also discussed.

Aflatoxins in food: occurrence, biosynthesis, effects on organisms, detection, and methods of control.

Oxidative degradation and detoxification of mycotoxins using a novel source of ozone.

Peanut meal containing aflatoxins was heat treated in the presence of moisture and chemicals to reduce the aflatoxin content. Treatments with ammonia, methylamine, sodium hydroxide and ozone were effective in either destroying aflatoxins or greatly reducing aflatoxin levels as indicated both by TLC analysis and feeding experiments with ducklings and rats. Weight gains for animals receiving the treated meals were essentially comparable to those for animals receiving aflatoxin-free meal. The treated meals, however, had somewhat reduced protein efficiency ratios, as indicated by rat feeding tests. Complete elimination of aflatoxins from contaminated peanut meal was achieved by extraction with a 90% acetone-10% water (w/w) solvent system. The extracted aflatoxin-free peanut meal gave good growth in the duckling and rat feeding tests, and had a relatively high protein efficiency ratio.

Elimination of aflatoxins from peanut meal.

Effect of heat on aflatoxins in oilseed meals

Organic and inorganic reagents have been tested for destruction or inactivation of the aflatoxins present in peanut and cottonseed meals. The treatments were made in a special laboratory-scale reactor, and were evaluated by determination of the aflatoxins in the products by thin layer chromatography. In some instances, a larger pilot-plant scale reactor was used. Ammonia, methylamine, sodium hydroxide and formaldehyde reduced aflatoxin levels and appear practical for large scale treatments. Effects of various reaction parameters including time, temperature and moisture content on the efficiency of these reagents are presented.

Chemical inactivation of aflatoxins in peanut and cottonseed meals

A peanut meal contaminated with ca. 600 ppb aflatoxins was treated with formaldehyde alone and in combination with calcium hydroxide in a benchscale reactor, operated both sealed and at atmospheric pressure. In general, thin layer chromatographic assays revealed that addition of calcium hydroxide to formaldehyde caused greater inactivation of the toxins than did formaldehyde alone. With the reactor sealed and 25% moisture in the meal, treatments for 1 hr with 0.5% and 1.0% formaldehyde plus 2.0% calcium hydroxide yielded products having 3 and 1 ppb aflatoxins, respectively, whereas under reflus at atmospheric pressure with 20% meal moisture, 1 hr treatment with 1.0% calcium hydroxide yielded a product with 5 ppb aflatoxins.

L. P. Codifer

Papers

Elimination of aflatoxins from peanut meal.

Effect of heat on aflatoxins in oilseed meals

Chemical inactivation of aflatoxins in peanut and cottonseed meals

Aflatoxin inactivation: treatment of peanut meal with formaldehyde and calcium hydroxide

Extraction of aflatoxins from cottonseed and peanut meals with ethanol