Moldy green coffee beans were found to contain Aspergillus ochraceus and detectable levels of ochratoxin A. The official first action method for the detection of ochratoxins in barley, 26.C15–26.C22, was modified for analysis of coffee beans and a number of survey samples of coffee beans were analyzed. A. ochraceus was found to be present in almost all samples but ochratoxin A was infrequently observed. Ochratoxin A production in sterile green coffee beans inoculated with A. ochraceus under optimal conditions was maximal at 13 days at room temperature but the total amount was low (450 μg/kg). Considerable destruction (approximately 80%) of ochratoxin A occurred during a heat treatment which simulated the roasting of coffee beans.

The effects of temperature and length of incubation on ochratoxin A production in various substrates were studied. The optimal temperature for toxin production by Aspergillus ochraceus NRRL-3174 was found to be around 28 C. Very low levels of ochratoxin A are produced in corn, rice, and wheat bran at 4 C. The optimal time for ochratoxin A production depends on the substrate, ranging from 7 to 14 days at 28 C. Ochratoxin B and dihydroisocoumaric acid, i.e., one of the hydrolysis products of ochratoxin A, were produced in rice but at levels considerably lower than ochratoxin A. No ochratoxin C was produced in rice at 28 C. When added to rice cereal or oatmeal, the toxin was found to be very stable over prolonged storage and even to autoclaving for 3 hr.

Wieners were formulated and processed approximating commercial conditions as closely as possible. Twenty-four batches of product were made with the

Samples of freshly harvested and remoistened corn, of various moisture contents, were stored at different temperatures; analyses for aflatoxin content were made periodically. At moisture levels above 17.5% and at temperatures of 24 C or warmer, aflatoxins were formed by Aspergillusflavus present in the original epiphytic mycoflora. Remoistened dried corn was subject to more rapid fungal deterioration and aflatoxin formation than freshly harvested corn. Screening of the fungi present in the corn revealed aflatoxin production only by A. flavus. The toxigenic strains produced only aflatoxins B1 and B2. corn was remoistened to moisture contents of 17 to 26%, stored at 24, 30, and 35 C, and handled as previously described. Aflatoxins were determined by using the aqueous acetone extraction method of Pons et al. (17). The 781

The effects of temperature and length of incubation on ochratoxin A production in various substrates were studied. The optimal temperature for toxin production by Aspergillus ochraceus NRRL-3174 was found to be around 28 C. Very low levels of ochratoxin A are produced in corn, rice, and wheat bran at 4 C. The optimal time for ochratoxin A production depends on the substrate, ranging from 7 to 14 days at 28 C. Ochratoxin B and dihydroisocoumaric acid, i.e., one of the hydrolysis products of ochratoxin A, were produced in rice but at levels considerably lower than ochratoxin A. No ochratoxin C was produced in rice at 28 C. When added to rice cereal or oatmeal, the toxin was found to be very stable over prolonged storage and even to autoclaving for 3 hr.