Growth of Salmonella on Inoculated Inhull Pistachios during Postharvest Handling.
Salmonella has been isolated from dried pistachios in both postharvest and retail surveys. The source of Salmonella in pistachios is unknown, but introduction is possible at points during production, harvest, and postharvest activities. To examine the behavior of Salmonella on pistachios during simulated postharvest conditions, early-, mid-, and late-season inhull pistachios were collected from two commercial processors over five different harvests. Pistachios were inoculated with cocktails of nalidixic acid- or rifampin-resistant Salmonella at 0.64 to 1.59 log CFU/g (low) or 2.73 to 3.27 or 4.29 to 4.31 log CFU/g (high) and were incubated for up to 30 h under commercially relevant conditions (23, 35, or 37°C and 50 or 90% relative humidity [RH]). Populations of Salmonella were measured by plating onto tryptic soy agar and CHROMagar Salmonella with added nalidixic acid or rifampin. Individual growth curves at the same temperature and RH differed significantly among different lots of pistachios. Except for a single late-season lot in which no significant growth was observed, Salmonella multiplied under all storage conditions. In the first 3 h after inoculation, insignificant (most cases) to small (0.41 to 0.67 log CFU/g) but significant ( P < 0.05) mean increases in Salmonella populations were measured; the mean predicted time to achieve maximum populations (5 to 8 log CFU/g) was 16 ± 4 h. In paired samples, longer lag phases, lower growth rates, and lower maximum increases were observed with inoculated inhull pistachios incubated at 23°C and 50% RH compared with 35 or 37°C and 90% RH. Similar growth curves were observed at the low and high inoculum levels; throughout the 30 h of incubation, Salmonella populations were consistently ∼1 to 2 log CFU/g lower on pistachios inoculated at the low inoculum level. Managing the time between harvesting and hulling will reduce the potential for growth of Salmonella on pistachios during postharvest handling.
Survival and Thermal Resistance of Salmonella Enteritidis PT 30 on Almonds after Long-Term Storage.
Salmonella survival and thermal resistance on the surface of almond kernels were evaluated after periods of storage. Almond kernels were inoculated with Salmonella enteritidis PT 30 and equilibrated to 0.45 water activity. Samples were separated into two groups (I and II) and stored in sealed metal cans at room temperature. Group I samples (stored 7, 15, 27, and 68 weeks) were re-equilibrated in controlled humidity chambers to 0.45 water activity before performing the thermal treatments after each storage period, but group II samples (stored 70 and 103 weeks) were thermally treated immediately after the cans were opened. For thermal treatments, individual almond kernels were vacuum sealed in thin plastic bags, heated isothermally in a water bath (80°C) for nine intervals, immediately cooled in an ice bath, and assayed for surviving Salmonella. Log-linear and Weibull models were fit to the inactivation data. Salmonella population decreased (P < 0.05) more than 2 log CFU/g during the long-term storage. Salmonella survival in group II at 70 weeks (7.3 log CFU/g) was higher (P < 0.05) than in group I (which had been re-equilibrated multiple times) at 68 weeks (6.2 log CFU/g). However, the thermal resistance of Salmonella enteritidis PT 30 did not decrease (P > 0.05) for up to 68 weeks of storage, and the log-linear model best described the thermal inactivation data. Overall, the results suggest that re-equilibrating almonds (group I) multiple times may have increased the rate of reduction of Salmonella populations during long-term storage. However, Salmonella thermal resistance on almonds appears to be essentially unaffected by long-term storage, which is important information for designing and conducting validation studies for pathogen control processes.
The false positive effect of residue of sulphur sources on dithiocarbamate analysis based on CS2 measurement.
Turkey plays an important role in the international trade of apricots as it has the largest production rate in the world. Since the sulphurisation process is allowed to be used for different products, the effect of residual sulphur and its compounds (which can be found in products as pesticide residues or additive residues) on the positive detection of carbon disulphide (CS2) still creates a big challenge in international trade. Therefore, the main objective of the present study was to investigate the effects of residues of sulphur or sulphur compounds on dithiocarbamate analysis methods based on CS2 measurement. In this study, apricots were chosen since they contain sulphur residues as a result of the sulphurisation process. Sulphur dioxide and dithiocarbamate analyses were conducted on dried apricots prepared with the sulphurisation process (SA) and without the sulphurisation process (NSA); analysis was by two different accredited laboratories. No of pesticide was applied to either SA or NSA samples. Although some of the NSA samples had <LOQ values, approximately 70 ± 32 mg/kg SO2and 0.061 ± 0.021 mg/kg dithiocarbamate were detected for NSA samples. On the other hand, for the SA sample group, 927-2915 mg/kg of SO2 and 0.265-0.825 mg/kg of dithiocarbamate were detected. Furthermore, a strong correlation between residual sulphur and dithiocarbamate values was observed. This study showed that the analysis method based on CS2 measurement may lead to false positive results for dithiocarbamates when residues of sulphur or sulphur compounds are found in products as pesticide or additive residues. Therefore, residual sulphur compounds as a result of the sulphurisation process (which is not considered during the evaluation of products) must be taken into account during the evaluation of products for dithiocarbamates.
Extending Storage Potential of De‐hulled Fresh Pistachios in Passive‐Modified Atmosphere.
BACKGROUND: The effects of passive-modified atmosphere packaging (passive-MAP) on the postharvest quality of de-hulled fresh pistachios (Pistacia vera L. cv. Kerman) stored at cold temperature (0 ± 0.5 °C) and 90 ± 1% R.H. was investigated with fruits under ambient air condition as the control treatment. The fruit quality parameters measured included kernel firmness, color values (L* , a* , b* , h°, and C* ), weight loss, fungal decay and marketability, ethylene production, respiration rate, and sensory characteristics at 0, 30, 60 and 105 days of storage. The CO2 and O2 concentrations in the package headspace were monitored during storage.
RESULTS: A modified atmosphere of 0.95%-3.35% O2 and 23.17%-29.82% CO2 was achieved in the passive-MAP treatment. Fruit respiration rates increased significantly relative to controls throughout storage, (P ≤ 0.01). However, storage had no significant effect on ethylene production rates. Additionally, passive-MAP stored fruits maintained firmness, shell lightness, kernel color and sensory quality with minimum weight loss and fungal decay, compared to the control. CONCLUSION: These results demonstrate storage life of fresh pistachios in passive-MAP can be extended up to 105 days, compared to 30 days in ambient conditions.
Determination of serotonin in nuts and nut containing products by liquid chromatography tandem mass spectrometry.
An ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the determination of serotonin in raw and roasted nuts (almond, Brazil nut, cashew, chestnut, coconut, hazelnut, Macadamia nut, pecan, peanut, pine nut, pistachio and walnut) as well as nut products (nut containing snack bars, chocolate and spreads) for the first time. Water extraction without prior defatting was performed to leach serotonin from complex matrices of nuts. Mean recoveries ranged from 64.2 ± 9.6 to 94.7 ± 20.1%. Limit of detection and limit of quantification were between 0.4 and 2.3 and 1.0-7.4 ng/g, respectively. Repeatability and reproducibility values were below 2%. Serotonin content of nuts ranged from 0.05 ± 0.01 (pine nut) to 155 ± 57.0 µg/g (walnut) in raw nuts while it was between 0.03 ± 0.00 (Macadamia nut) and 15.3 ± 1.27 µg/g (pecan) in roasted nuts. Serotonin in nut products was found to range from 0.09 ± 0.00 to 8.99 ± 0.92 µg/g, depending on the nuts they contain.
Peanut Allergy in Spanish Children: Comparative Profile of Peanut Allergy versus Tolerance.
BACKGROUND: Peanut storage proteins (Ara h 1, Ara h 2, and Ara h 3) have been described as the major peanut allergens in children, although not all peanut-sensitized individuals have clinical reactivity after exposure. OBJECTIVES: We studied the sensitization profile of peanut-allergic and peanut-tolerant children in a pediatric cohort. METHODS: The clinical features and sensitization profile to the peanut storage proteins Ara h 9 and Pru p 3 were compared between peanut-allergic and peanut-tolerant children using component-resolved diagnostics. RESULTS: Thirty-three peanut-sensitized children were included: 22 allergic and 11 tolerant patients. Seventy-two percent of the peanut-allergic children were sensitized to at least one peanut storage protein. The rates of sensitization to Ara h 1, Ara h 2, and Ara h 3 were 63.6, 68.1, and 68.1%, respectively, among the peanut-allergic children and 27.2, 18.1, and 45.4% among the peanut-tolerant children. IgE from the sera of 18% of the peanut-allergic patients recognized Ara h 9, whereas no sensitization to Ara h 9 was detected in the peanut-tolerant children. A total of 59% of the peanut-allergic and 27% of the peanut-tolerant children were sensitized to Pru p 3. Sensitization to Ara h 1 and Ara h 2 was more frequent among the peanut-allergic children (p < 0.05). Although the levels of specific IgE against peanut storage proteins were higher in peanut allergy, there were not statistically significantly different from the levels in peanut tolerance, probably due to the small number of patients included. CONCLUSIONS: In our population, the peanut-allergic children were mainly sensitized to peanut storage proteins, and Ara h 2 sensitization allows a more accurate diagnosis of clinical reactivity to peanuts. More than half of the peanut-allergic patients were sensitized to peach Pru p 3, and 50% of them had fruit allergy at the time of the study.
The functional biology of peanut allergens and possible links to their allergenicity
Peanut is one of the most common food triggers of fatal anaphylaxis worldwide although peanut allergy affects only 1-2% of the general population. Peanuts are the source of highly potent allergenic proteins. It is emerging that the allergenicity of certain proteins is linked to their biological function. Peanut is an unusual crop in that it flowers above ground but produces its seed-containing pods underground. This so called geocarpic fruiting habit exposes pods and seeds during their development to soilborne pathogens and pests. Pest damage can also open routes of entry for opportunistic fungi such as Aspergillus. Although seed proteins have primary functions in nutrient reservoirs, lipid storage bodies, or the cytoskeleton, they have also evolved to act as part of the plant's defense system to enhance fitness and survival of the species. When interacting with pathogens or pests, these proteins modify and damage cells' membranes, interact with immune receptors and modulate signaling pathways. Moreover, following exposure, the immune system of predisposed individuals reacts to these proteins with the production of specific IgE. This review explores the evolutionary biology of peanut and its seed proteins and highlights possible links between the proteins' biological function and their allergenicity.
Seminar: Discover Turkish Organics, February 15, BIOFACH, Nuremberg (Germany)
Join the Seminar: Discover Turkish Organics at Mailand, Nürnberg Convention Center Mitte, Level 1.
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BIOFACH is the place where people share their passionate interest in organic food, get to know each other and exchange views, and this since 1990.
American Pistachio Industry Annual Conference
The pistachio industry's biggest event of the year will take place once again at the picturesque JW Marriott Resort & Spa, in Palm Desert, February 25-27, 2019. APG19's program will be filled with important organization and industry updates, informative sessions, and educational opportunities.
https://www.apgpower.org/apc19/