Farm to table: Residues of different pesticides in tomato and tomato juice - Food safety aspects.

During plant cultivation, the pesticides can get into the tissue of vegetables due to crop protection processes, and thus into the food chain. Therefore, they constitute a potential risk to the consumer's health. Depletion of pesticides [spirotetramat (Movento), azoxystrobin and difenoconazole (Amistar Top)] was monitored by testing tomatoes treated individually or simultaneously and tomato juices prepared from the treated tomatoes. The investigations aimed to reveal any kinetic interaction between the compounds tested and changes in their elimination, and thus to assess their compliance with the official Maximum Residue Limits (MRLs). The co-presence of pesticides prolonged the elimination of the individual compounds which reached significantly higher residue levels (P < 0.0001) in tomato, especially difenoconazole (45%) and azoxystrobin (50%) on day 8 after treatment that can cause food safety issues to the human consumers. However, the concentrations of pesticides applied alone or simultaneously were found to be below the corresponding MRL values after the withdrawal period in all investigated tomato and tomato juice samples. Accordingly, the investigated pesticides can be safely used simultaneously, their concentrations are in compliance with the legal regulations and thus their concomitant presence does not pose any risk to the consumers' health.

Effect of Combination of Time and Temperature on Quality Characteristics of Sous Vide Chicken Breast.

The use of minimal thermal processing techniques such as sous vide technology to improve the quality of meat-based foods has gained a special focus in recent years. A proper combination of temperature and time parameters in sous vide processing plays an important role in the water-holding capacity, texture properties, and juiciness of the meat. The present study aimed to assess the impact of the one-step and two-step sous vide processing on different quality properties of chicken breast with special emphasis on the cooking loss, color, texture properties, protein solubility, and lipid oxidation. According to the results, chicken breast treated with a two-step temperature (50 and 60 °C) showed improved texture parameters (shear force, hardness, chewiness, and gumminess), lower cooking loss, acceptable redness values, and decreased lipid oxidation levels than the chicken breast treated with the one-step temperature of 60 °C. Moreover, the two-step sous vide technique revealed significantly higher total protein solubility of the chicken breast than the one-step sous vide. Based on pasteurization values, the two-step sous vide technique was equally safe as the one-step sous vide technique for vegetative cells' inactivation for the main pathogens of interest (C. perfringens and L. monocytogenes).

Possible inhibitory effect of microbial transglutaminase on the formation of biogenic amines during Trappist cheese ripening.

Trappist cheese (semi-hard, rennet-coagulated cheese with round eyes) was manufactured and matured for 4 weeks at 12 ± 1°C, 85% relative humidity (RH). The effect of microbial transglutaminase (MTGase) was followed by measuring the levels of free amino acids (FAAs) and biogenic amines (BAs) every 2 weeks during 4 weeks of cheese ripening. Results show that MTGase can decrease the cadaverine production by 30%, but only at the initial stage of ripening. Application of MTGase results in 49% less putrescine, 12% less tyramine production at the end of 4 weeks ripening time, and can decrease histamine levels by 8% after 2 weeks of ripening time in the examined semi-hard cheese type.

Transfer of certain beta-lactam antibiotics from cow's milk to fresh cheese and whey.

The aim of this study was to investigate the transfer of cephalexin, penicillin-G, and ampicillin & cloxacillin from cow's milk to cheese and whey. For this purpose, raw milk was artificially contaminated to different antibiotic levels and then heat-treated to prepare fresh cheese from it. Antibiotic levels of the milk, whey and cheese were measured with LC-MS/MS. The extent of heat degradation was not sufficient to remove the antibiotic residues from milk. Antibiotic concentrations in whey and fresh cheese were in good accordance with the concentration of the same compound in milk suggesting that contamination of the milk will result in contamination of the product. The investigated antibiotics were transferred less into the cheese curd (1.6-12.5% of the original amount), than into the whey (33.2-74.1%). For penicillin-G even 100% (complete removal) was experienced.

Possible food safety hazards of ready-to-eat raw fish containing product (sushi, sashimi).

It is undeniable that with the popularity of sushi and sashimi over the last decade the consumption of raw fish has extremely increased. Raw fish is very appreciated worldwide and has become a major component of human diet because of its fine taste and nutritional properties. Possible hazards concerning fish safety and quality are classified as biological and chemical hazards. They are contaminants that often accumulate in edible tissue of fish and transmit to humans via the food chain affecting the consumer's health. Although their concentration in fish and fishery products are found at non-alarming level of a daily basis period, they induce hazardous outcome on human health due to long and continuous consumption of raw fish. Regular sushi and sashimi eaters have to be aware of the contaminants found in the other components of their dish that often add up to acceptable residue limits found in fish. Hence, there is the urge for effective analytical methods to be developed as well as stricter regulations to be put in force between countries to monitor the safety and quality of fish for the interest of public health.

Predictive Correlation between Apparent Sensory Properties and the Formation of Heterocyclic Amines in Chicken Breast as a Function of Grilling Temperature and Time.

In the present set of experiments, we studied the correlation between the heterocyclic amine (HCA) concentration and the color changes of the chicken breast with or without skin during grilling under open or closed conditions as a function of the applied temperature and time. The concentration of the HCAs formed during grilling was measured by a validated LC-MS/MS method, whereas the color changes were determined either instrumentally or by visual observation. In general, higher temperatures and longer heat treatment times resulted in a more substantial HCA formation, especially on the surface of the samples and in the skin, where the total levels reached 746 ng/g. Results of regression analysis demonstrate a strong correlation (r > 0.7) between the HCA content of the grilled chicken breast and the L* and a* values indicating the significance of brightness and the red parameter of the color scale, respectively. In the case of open grilling, the skinless breast samples showed correlation (r > 0.7) between the HCA content and the color analysis results in both the full sample and the crust, respectively. Breast samples with skin exhibited the same level of correlation when they were grilled closed. In the case of open grilling the breast with skin, and closed-grilling the skinless breast, the linear regression analysis yielded a weaker correlation (0.7 > r > 0.4 or less) between the HCA concentrations and the color. Our results demonstrate that there is a predictive correlation between the color changes perceptible for the consumers and the HCA formation during grilling of chicken breast as a function of time and temperature depending on the type of grilling and the presence of skin.

Determination of mTG Activity in Low-Fat Semi-Hard Cheese Using Fluorescent Labelling.

A method to directly determine enzyme activity in cheese has not been published yet despite the fact that mTG mediated gel strength or hardness modification may be unpredictable and unfavorable during ripening and/or storage. The present study was performed to determine enzyme activity of semi-fat semi-hard Hungarian Trappist cheese. The widely known hydroxamate method was not suitable to even detect enzyme treatment, because of the disturbing effect of milk proteins. However incorporation of a dansylated glutamine dipeptide into milk protein contributed to monitoring the enzyme activity. The fluorescent measurement reflected mTG activity by increasing fluorescence intensity at 532 nm in a 5-min continuously running assay. The presented dipeptide assay allows the determination of enzyme activity after 2 min measurement by the manufacturing stage: cutting and up-heating. This assay can be used to monitor mTG activity during manufacture of low-fat semi-hard cheese type, in case if it was produced according to general recommendation of enzyme preparation providers (enzyme dosage: 0.1%, v/w). According to the preliminary calibration this assay can define mTG activity in the range of 0.05-0.3 U/g.