Aflatoxins are toxic metabolites produced by a variety of molds such as Aspergillus flavus and Aspergillus parasiticus. Aflatoxins have been associated with various diseases, such as aflatoxicosis. They are carcinogenic and can be present in grains, nuts, cottonseed, crops and other commodities associated with human food or animal feeds. This discovery has led to a growing awareness of the potential hazards of these substances as contaminants of food and feed causing illness and even death in humans and other mammals. these studies also revealed that there are four major aflatoxins: B1, B2, G1, G2 plus two additional metabolic products, M1 and M2, that are of significance as direct contaminants of foods and feeds.
Contamination happen when cows are fed with contaminated feed aflatoxin B1, B2, G1, G2, then aflatoxin B1 is converted by hydroxylation to aflatoxin M1, which is subsequently secreted in the milk of lactating cows. Aflatoxin M1 is quite stable towards the normal milk processing methods such as pasteurization and if present in raw milk, it may persist into final products for human consumption. Most controlling government agencies worldwide have regulations regarding the amount of aflatoxins allowable in human and animal foodstuffs. Many countries have declared limits for the presence of aflatoxin M1 in milk and milk products. In the EU the limit for the presence of M1 in milk and reconstituted milk powders has been set at 0.05 mg/L or 50 parts per trillion (50 ppt.)
Deep frying is a cooking method in which food is submerged in hot oil or fat. Overheating or over-using the cooking oil can pose hazards due to oil deterioration, polymerization, oxidation, and harmful components formation such as acrylamide. Deterioration of cooking oils is generally followed by changes in color of the used oil , free fatty acid level, an increase in trans fat, Polycyclic aromatic hydrocarbons (PAHs) and polarity of the oil.
The level of polar components or total polar compounds is a good indicator to determine the quality of oil. The maximum levels for polar compounds of cooking oils is at 25g/100 g oil or 25%
People who believe in taking bird’s nest as tonics may have another hazard to look out for.
According to the Deputy Minister of Agriculture in Malaysia, Cai Zhi Yong, red blood bird’s nest is not actually stained red by blood.
He explains that the red colour actually comes from the bird's nest being contaminated by bird droppings.
This phenomenon has led to a black market where unscrupulous dealers artificially create red blood bird's nest by using a preservative made from bird's poop.
This preservative acts as a red pigment which is used to disguise ordinary and cheaper bird’s nest.
The preservative contains hydrochloric acid nitrate that exceeds the acceptable amount for human consumption.
According to Malaysia's Ministry of Health, food must not contain more than 70ppm of the substance, but red blood bird's nest may contain up to 2,220ppm of the toxic chemical.
Local retailers are on the lookout to prevent the import of these dangerous and treated red blood bird’s nest.
An experienced bird’s nest dealer, Lin Ming Jian, says: “This kind of fake treated bird’s nest will not expand after being soaked in water, unlike the real deal which can expand up to 7 – 8 times. The pigment will seep out quickly too.”
Up to 70% of the bird’s nest in Singapore is imported from Indonesia. The rest comes from Malaysia and Thailand.
There are several common beliefs concerning red blood bird’s nest.
One belief is that the swallows spit blood after they eat lotus seeds, and the spit stains their nests red.
Another belief is that the nests are stained red by the minerals from the rock walls that the nests are built on.