The evaluation of Zataria multiflora Boiss. essential oil effect on biogenic amines formation and microbiological profile in Gouda cheese.

UNLABELLED: The effect of Zataria multiflora Boiss. (Z. multiflora) essential oils (EO) on biogenic amines (BAs) production and microbial counts in Gouda cheese has been investigated. Zataria multiflora was added to milk in different concentrations (0·05, 0·1, 0·2 and 0·4% (v/v)). The BAs (tyramine and histamine) were measured by RP-HPLC, following extraction from the cheese. Various microbiological analyses (aerobic mesophilic bacteria, enterococci, mesophilic lactobacilli, Enterobacteriaceae, lactococci and yeasts) were performed during ripening using the viable plate count method on specific culture media. The overall acceptability of cheeses was investigated by seven panellists. All the samples containing different concentrations of EO were acceptable to the panellists. Also, Gouda cheeses with 0·2% Z. multiflora EO showed the highest acceptability among all the samples. At the end of maturation period, 0·1, 0·2 and 0·4% Z. multiflora EO reduced tyramine and histamine significantly to 5%, 22% and 44% for tyramine and 14%, 29% and 46% for histamine, respectively, when compared to the control group. The increase of Z. multiflora EO concentrations led to further decrease in BAs content and microbial counts. The maximum microbiological reduction was observed in yeasts, and minimum microbiological reduction was seen in Enterobacteriaceae counts. Zataria multiflora EO could be used for reduction of BAs and also as a flavouring agent in Gouda cheese and could contribute to consumers' health. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of biogenic amines in cheese has a serious impact on public health. Besides, there is growing concern about the use of chemical preservatives and the food industry is looking for new natural preservation methods. Zataria multiflora Boiss. essential oil is well known for its antimicrobial effects, and we attempted to reduce biogenic amines formation in Gouda cheese using Z. multiflora Boiss. essential oil as a natural additive. Furthermore, the desirable organoleptic qualities such as flavour, odour, texture and colour were achieved by adding Z. multiflora Boiss. to cheese.

Analytical study of 226Ra activity concentration in market consuming foodstuffs of Ramsar, Iran.

BACKGROUND: Ramsar, a city of Iran located on the coast of the Caspian Sea, has been considered to be enormously important due to its high natural radioactivity levels. People living in High Level Natural Radiation Areas (HLNRAs) have been exposed by several sources, one of which could be foodstuff. However, many studies have been carried out to measure the environmental radioactivity in Ramsar, but no survey has been conducted in all stapled consumed foods yet. This study was dedicated to determine 226Ra activity concentration in the daily diets of Ramsar residents as a probable exposure. METHODS: Approximately 70 different market samples were collected during the four seasons based on the daily consumption patterns of residents which have the highest consumption and their availability in the seasons. All samples, after washing, drying and pretreatment, were analyzed for 226Ra radionuclide determination by α-spectrometry. RESULTS: The mean radioactivity concentration of 226Ra ranged between 7 ± 1 mBq Kg-1 wet weight in meat, and 318 ± 118 mBq Kg-1 for tea dry leaves. The 226Ra activity concentrations in collected samples varied from below the minimum detectable activity up to 530 ± 30 mBq Kg-1. To compare the results with United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) reference values, the 226Ra activity concentrations concluded from the results appear to be higher in milk, chicken and eggs and less in grain products, vegetables, fruits and fish products. These results indicate that no significant 226Ra contamination is present in market foodstuffs and provide reference values for the foodstuffs in Ramsar. CONCLUSIONS: Of the total daily dietary 226Ra exposure from market consuming foodstuffs for adults in Ramsar, the largest percentage was from wheat. The residents consuming wheat and manufacturing wheat products such as bread, pasta, porridge, crackers, biscuits, pancakes, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, breakfast cereals and so on may receive an elevated dose in the diet. In conclusion, with regards to presence of 226Ra in foodstuffs it is necessary to monitor regularly the activity of 226Ra in foodstuffs including market and local foods.