aflatoxin-m1 and brine

The effect of feta cheese manufacture on aflatoxin M(1) (AFM(1)) content was studied using an enzyme immunoassay technique. Feta cheese was made from milk spiked with 1 and 2 microg AFM(1) per kilogram milk. Pasteurization at 63 degrees C for 30 min caused <10% destruction of AFM(1). During cheese making, the remaining AFM(1) in milk was partitioned between curd and whey with two-thirds retained in the curd and one-third going into the whey. Cheeses were then stored for 2 mo in 8%, 10%, and 12% brine solutions at 6 and 18 degrees C. There was a 22% to 27% reduction of AFM(1) during the first 10 d of storage, with slightly more loss as salt concentration increased and when the cheese was stored at 18 degrees C. Further storage caused only slight decrease in AFM(1) and after 30 d of brining there was no difference in AFM(1) content of the cheese based upon salt concentration of the brine. At 18 degrees C, no further losses of AFM(1) occurred after 30 d, and at 6 degrees C, there was continued slight decrease in AFM(1) levels until 50 d. After 60 d of brining, there was a total loss of 25% and 29% of the AFM(1) originally present for cheese brined at 6 and 18 degrees C, respectively. Thus, the combination of pasteurization, conversion of milk into feta cheese, and at least 50 d storage of cheese in brine caused a total loss of about 50% of the AFM(1) originally present in the raw milk.

Topics: Aflatoxin M1; Animals; Cheese; Colony Count, Microbial; Enzyme-Linked Immunosorbent Assay; Food Handling; Food Microbiology; Hot Temperature; Immunoenzyme Techniques; Milk; Milk Proteins; Salts; Sodium Chloride; Time Factors; Whey Proteins

The distribution of aflatoxin M(1) (AFM(1)) has been studied between curd, whey, cheese and pickle samples of Turkish white pickled cheese produced according to traditional techniques and its stability studied during the ripening period. Cheeses were produced in three cheese-making trials using raw milk that was artificially contaminated with AFM(1) at the levels of 50, 250 and 750 ng/l and allowed to ripen for three months. AFM(1) determinations were carried out at intervals by LC with fluorescence detection after immunoaffinity column clean-up. During the syneresis of the cheese a proportionately high concentration of AFM(1) remained in curd and for each trial the level was 3.6, 3.8 and 4.0 times higher than levels in milk. At the end of the ripening, the distribution of AFM(1) for cheese/whey + brine samples was 0.9, 1.0 and 1.3 for first, second and third spiking respectively indicating that nearly half of the AFM(1) remained in cheese. It has been found that only 2-4% of the initial spiking of AFM(1) transferred into the brine solution. During the ripening period AFM(1) levels remained constant suggesting that AFM(1) was quite stable during manufacturing and ripening.

Topics: Aflatoxin M1; Animals; Carcinogens, Environmental; Cattle; Cheese; Chromatography, High Pressure Liquid; Condiments; Food Contamination; Food Handling; Milk; Salts; Time Factors; Turkey