Title : Effects of yoghurt manufacturing procedures on poly cyclic aromatic hydrocarbons in milk
Abstract:
The study was conducted to throw more light on the changes of polycyclic aromatic hydrocarbons (PAHs) concentration in milk introduced for yoghurt manufacture steps till 120 hours of cold storage. It was clear that heat treatment at 90?C for 20 minutes during manufacture of yoghurt showed total reduction % of Σ18 and % Σ4 (sum BaA, CHR, BbF and BaP) PAHs in all artificially injected milk samples about 71.5, 90.95%, respectively. Furthermore, after heat treatment both Benzo[ghi]perylene and Dibenz[a,h]Anthracene in addition to Benzo[b]fluoranthene were not detected in all artificially injected milk samples. Consequently, reduce the daily intake of PAHs from contaminated milk with PAHs by the effect of heat treatment. However, slight increasing level of PAHs after yoghurt curd formation of incubation at zero time at pH 4.75. Although the presence of PAHs in milk intended for yoghurt manufacture does not affect yoghurt starter culture development and their role in conversion of lactose to lactic acid which is the cause of low pH in yoghurt. Therefore, the construction of curd during the incubation period occurs in an appropriate manner. The reduction of PAHs concentration proved that PAHs affected by both cold storage and pH changes in yoghurt curd. The reduction of PAHs by yoghurt starter maybe related to pH effects during incubation periods, several authors labelled pH as a factor. The highest reduction in yoghurt samples during cold storage was detected after 72 hr. of storage and was found at pH 4.51, with mean reduction percentage 31.25% for Total (Σ18 PAHs) and 74.92% for Total (Σ4 PAHs). The highest reduction was recorded with the compound CHR with reduction rate 90%.
Collectively, it could be concluded that, milk and its products are daily used, thus the exposure to PAHs is unavoidable, highlighting the carcinogenic potential of such compounds on long term exposure particularly for infants and babies. Nowadays, in the food industry it is very common to use starter cultures to improve the characteristics of the food products, and the possibility that these beneficial microorganisms in the food sector has a long tradition, namely lactic acid bacteria would degrade these contaminants is of great interest.
Audience Take Away:
- Audience will expand their knowledge about what are Polycyclic aromatic hydrocarbons (PAHs), it’s health effect, where they come from, how we exposed to them and how to reduce the exposure.
- provide new information about food industry as it is very common to use starter cultures (LAB) to improve the characteristics of the food products, and the possibility that these microorganisms would degrade these contaminants as PAHs.
- Food quality and safety is a pertinent issue, consumers are concerned that their food should be both of high nutritional value and free from chemical residues.
- Audience will get a knowledge about the important to reduce the concentrations of PAHs and minimize health problems.
- Audience will get a knowledge about the carcinogenic potential of such compounds on long term exposure particularly for infants and babies, especially milk and its products are daily used, thus recommended that heat treatment play an important role in decreasing some contaminants as PAHs and may be effective in the reduction of the daily intake of PAHs containing food.