In-Depth Investigation of the Safety of Wooden Shelves Used for Traditional Cheese Ripening.

The main goal of this research was to characterize the bacterial diversity of the wooden boards used for aging traditional Sicilian cheeses and to evaluate whether pathogenic bacteria are associated with these surfaces. Eighteen cheese dairy factories producing three traditional cheese typologies (PDO Pecorino Siciliano, PDO Piacentinu Ennese, and Caciocavallo Palermitano) were selected within the region of Sicily. The wooden shelf surfaces were sampled by a destructive method to detach wood splinters as well as by a nondestructive brushing to collect microbial cells. Scanning electron microscopy showed the presence of almost continuous bacterial formations on the majority of the shelves analyzed. Yeasts and fungal hyphae were also visualized, indicating the complexity of the plank communities. The amplicon library of the 16S rRNA gene V3-V4 region was paired-end sequenced using the Illumina MiSeq system, allowing the identification of 14 phyla, 32 classes, 52 orders, 93 families, and 137 genera. Staphylococcus equorum was identified from all wooden surfaces, with a maximum abundance of 64.75%. Among cheese-surface-ripening bacteria, Brevibacterium and Corynebacterium were detected in almost all samples. Several halophilic (Halomonas, Tetragenococcus halophilus, Chromohalobacter, Salimicrobium, Marinococcus, Salegentibacter, Haererehalobacter, Marinobacter, and Idiomarinaceae) and moderately halophilic (Salinicoccus, Psychrobacter, and Salinisphaera) bacteria were frequently identified. Lactic acid bacteria (LAB) were present at low percentages in the genera Leuconostoc, Lactococcus, Lactobacillus, Pediococcus, and Streptococcus. The levels of viable microorganisms on the wooden shelves ranged between 2.4 and 7.8 log CFU/cm2. In some cases, LAB were counted at very high levels (8.2 log CFU/cm2). Members of the Enterobacteriaceae family were detected in a viable state for only six samples. Coagulase-positive staphylococci, Salmonella spp., and Listeria monocytogenes were not detected. Seventy-five strains belonged to the genera Leuconostoc, Lactococcus, Pediococcus, Enterococcus, Lactobacillus, and Weissella. IMPORTANCE This study provides evidence for the lack of pathogenic bacteria on the wooden shelves used to ripen internal bacterially ripened semihard and hard cheeses produced in Sicily. These three cheeses are not inoculated on their surfaces, and surface ripening is not considered to occur or, at least, does not occur at the same extent as surface-inoculated smear cheeses. Several bacterial groups identified from the wooden shelves are typically associated with smear cheeses, strongly suggesting that PDO Pecorino Siciliano, PDO Piacentinu Ennese, and Caciocavallo Palermitano cheese rind contributes to their final organoleptic profiles.

Mining the Factors Driving the Evolution of the Pit Mud Microbiome under the Impact of Long-Term Production of Strong-Flavor Baijiu.

The mud cellar creates a unique microenvironment for the fermentation of strong-flavor baijiu (SFB). Recent research and long-term practice have highlighted the key roles of microbes inhabiting pit mud in the formation of SFB's characteristic flavor. A positive correlation between the quality of SFB and cellar age was extracted from practice; however, the evolutionary patterns of pit mud microbiome and driving factors remain unclear. Here, based on the variation regularity analysis of microbial community structure and metabolites of samples from cellars of different ages (∼30/100/300 years), we further investigated the effects of lactate and acetate (main microbial metabolites in fermented grains) on modulating the pit mud microbiome. Esters (50.3% to 64.5%) dominated the volatile compounds identified in pit mud, and contents of the four typical acids (lactate, hexanoate, acetate, and butyrate) increased with cellar age. Bacteria (9.5 to 10.4 log10 [lg] copies/g) and archaea (8.3 to 9.1 lg copies/g) mainly constituted pit mud microbiota, respectively dominated by Clostridia (39.7% to 81.2%) and Methanomicrobia (32.8% to 92.9%). An upward trend with cellar age characterized the relative and absolute abundance of the most predominant bacterial and archaeal genera, Caproiciproducens and Methanosarcina. Correlation analysis revealed significantly (P < 0.05) positive relationships between the two genera and major metabolites. Anaerobic fermentation with acetate and lactate as carbon sources enhanced the enrichment of Clostridia, and furthermore, the relative abundance of Caproiciproducens (40.9%) significantly increased after 15-day fed-batch fermentation with lactate compared with the initial pit mud (0.22%). This work presents a directional evolutionary pattern of pit mud microbial consortia and provides an alternative way to accelerate the enrichment of functional microbes. IMPORTANCE The solid-state anaerobic fermentation in a mud cellar is the most typical feature of strong-flavor baijiu (SFB). Metabolites produced by microbes inhabiting pit mud are crucial to create the unique flavor of SFB. Accordingly, craftspeople have always highlighted the importance of the pit mud microbiome and concluded by centuries of practice that the production rate of high-quality baijiu increases with cellar age. To deepen the understanding of the pit mud microbiome, we determined the microbial community and metabolites of different-aged pit mud, inferred the main functional groups, and explored the forces driving the microbial community evolution through metagenomic, metabolomic, and multivariate statistical analyses. The results showed that the microbial consortia of pit mud presented a regular and directional evolutionary pattern under the impact of continuous batch-to-batch brewing activities. This work provides insight into the key roles of the pit mud microbiome in SFB production and supports the production optimization of high-quality pit mud.

Efficacy of different hermetic bag storage technologies against insect pests and aflatoxin incidence in stored maize grain.

The performance of six grain storage technologies for the control of insect pests in maize was evaluated over a 36-week (9-month) storage period. The six technologies used were: two ZeroFly® hermetic bag brands (laminated and non-laminated); Purdue Improved Crop Storage (PICS) bag; non-hermetic ZeroFly® bag; woven polypropylene (PP) bag containing maize grain treated with Actellic Gold® Dust (pirimiphos-methyl 1.6% + thiamethoxam 0.3%) and woven PP bag containing untreated grain. Each bag was filled with 50 kg maize grain and four replicates of each were set up. With the exception of the non-hermetic ZeroFly® bag, 50 live adults of the larger grain borer Prostephanus truncatus and of the maize weevil Sitophilus zeamais, were introduced into all the bags. Insects were not introduced into the non-hermetic ZeroFly® bag to assess its effectiveness in repelling infestation from outside. Parameters recorded were gas composition (oxygen and carbon dioxide) levels inside the bags; weight of flour generated by insect feeding activities; grain moisture level; live adult insect counts; grain damage and weight loss; grain germination rate and aflatoxin level. At termination, the plastic liners of the hermetic bags were examined for perforations. Results show that oxygen depletion and carbon dioxide evolution were faster in ZeroFly® hermetic compared to PICS bags. Throughout the 36-week storage trial, grain damage remained below 4% and weight loss below 3% in all the treatments except in the untreated PP bags in which it increased to 81.1 and 25.5%, respectively. The hermetic PICS, ZeroFly® and Actellic Gold dust-treated PP bags maintained grain germination at 60%, which was lower than the initial 90%, while in untreated control, it reduced to 4.7%. The mean aflatoxin levels fluctuated between 0.39 and 3.56 parts per billion (ppb) during 24 weeks of storage in all the technologies tested, which is below the acceptable maximum level of 10 ppb in maize. Based on the evaluation results, it can be concluded that hermetic PICS and ZeroFly® bags and woven PP bag with Actellic Gold dust-treated grain effectively protected stored maize grain from insect attack and weight losses. Appropriate strategies and mechanisms for the effective and efficient adoption of hermetic storage bag technology at scale would contribute towards global food security.

Low storage temperature for tree ripe mangoes under controlled atmospheres with elevated CO2 concentrations.

BACKGROUND: Tree-ripe mangoes are of a better quality than the more commonly marketed mature-green fruit. However, the postharvest life of tree-ripe mangoes at the chilling threshold temperature for mature-green fruit of 12 °C is insufficient to allow long distance transport for international marketing. Because the chilling sensitivity often decreases as fruit ripen, lower temperatures (5 and 8 °C) in combination with a controlled atmosphere of 5 kPa O2 plus 10 or 25 kPa CO2 were tested to determine whether the quality of tree-ripe mangoes could be maintained longer without chilling injury (CI). RESULTS: Tree-ripe 'Tommy Atkins' and 'Keitt' mangoes were stored for 14 or 21 days, respectively, in air or controlled atmosphere (CA) at 5 or 8 °C. Respiration rates were below 10 mL kg-1 h-1 during CA storage and increased three-fold during a 3-day shelf life period at 20 °C. Ethanol synthesis of fruit stored in 25 kPa CO2 , but not 10 kPa CO2 , increased during storage and remained high during shelf life, indicating physiological stress. Elevated electrolyte leakage and 1-aminocyclopropane-1-carboxylic acid concentrations in both cultivars stored in 25 kPa CO2 also indicated that mesocarp tissues were injured by the higher CO2 level. No CI symptoms were observed in air or CA at either 5 or 8 °C. CONCLUSION: Storage of tree-ripe mangoes in 5 kPa O2 plus 10 kPa CO2 at either 5 or 8 °C best maintained the quality of Tommy Atkins and Keitt fruit for 14 or 21 days, respectively, without evidence of either atmosphere injury or CI. © 2020 Society of Chemical Industry.

How olive washing and storage affect fruit ethanol and virgin olive oil ethanol, ethyl esters and composition.

BACKGROUND: Olives are stored for a short time after harvesting pending processing in the oil mills. Furthermore, olives are often washed prior to fruit storage. In this work we study how washing and storage affect fruit ethanol content and the effect on virgin olive oil ethanol content and quality. RESULTS: Olive storage produced an increase in the fruit ethanol content, achieving values six times higher when storage was in silos. Washing the olives resulted in an increase in fruit ethanol content, although when washed olives were processed immediately no difference was found. The increase in fruit ethanol content during storage was reflected in higher oil ethanol concentration. Similarly, olive washing resulted in oils with higher ethanol concentration. Industrial conditions gave more important increases in oil ethanol content than that from olives processed by hand. For quality parameters all the olive oils were classified as 'extra virgin'. In general, oils showed a slight decrease in some sensory attributes. At industrial scale after 24 h storage oils were classified as 'virgin' because sensory defects were found. CONCLUSION: Olive storage should be avoided or reduced to less than 12 h; if possible, olives should not be washed before storage since this practice favors losses in sensory characteristics and the synthesis of ethanol, a precursor of ethyl esters. © 2020 Society of Chemical Industry.

Direct analysis in real time coupled with quadrupole-Orbitrap high-resolution mass spectrometry for rapid analysis of pyrethroid preservatives in wooden food contact materials.

A methodology is presented for the determination of four pyrethroid (PYR) preservatives in wooden food contact materials (FCMs) using direct analysis in real time (DART) coupled with quadrupole-Orbitrap high-resolution mass spectrometry (Q-Orbitrap HRMS). The sampling mode and critical parameters of the DART-Q-Orbitrap HRMS protocol were systematically investigated. Good linearity was achieved for the four analytes with correlation coefficients all greater than 0.99. The limits of detection (LODs) and limits of quantitation (LOQs) of the method were in the range of 0.04-0.20 mg kg-1 and 0.10-0.50 mg kg-1, respectively. The mean recoveries ranged from 72.1% to 82.7% with relative standard deviations (RSDs) from 5.2% to 11.8% at three spiked levels. The developed method was proved to be suitable for rapid screening of PYRs in complex wooden FCM samples to ensure product safety and consumer health.

Effects of temperature on protein phosphorylation in postmortem muscle.

BACKGROUND: Phosphorylation is one of the most important post-translational modifications. Currently, many postmortem protein phosphorylation studies in muscle have been related to meat quality such as tenderness and color stability. However, the effects of various storage temperatures (25, 15, 4 and -1.5 °C) on the phosphorylation level of protein are poorly understood. Changes in the protein phosphorylation levels in postmortem ovine muscle at various storage temperatures were determined in this study. RESULTS: The obtained data showed that pH decline rate was significantly inhibited at -1.5 °C from 12 h to 7 days postmortem (P < 0.05). The ATP consumption rate was higher at 25 °C than that at other three temperatures (P < 0.05). Analysis of the temperature, pH and ATP content revealed that the ATP content was related to the phosphorylation levels of individual protein bands. Phosphorylated myofibrillar and sarcoplasmic proteins, such as myosin binding protein C, troponin T3, myosin light chain 1, glucose-6-phosphate isomerase and pyruvate kinase, were mainly involved in glycolysis and muscle contraction. CONCLUSION: The global and specific protein phosphorylation levels can be influenced by the postmortem storage temperature of muscle. Phosphorylation of proteins was correlated with glycolysis and muscle contraction. Certain phosphorylated proteins, such as heat shock proteins, require further study to clarify their effects on meat traits. © 2019 Society of Chemical Industry.

Changes in flavor of fragrant rice during storage under different conditions.

BACKGROUND: Because of its high nutritional value and good sensory properties, fragrant rice is very popular all over the world. The aroma and taste of fragrant rice play an essential role in its sensory properties. However, there has been a lack of studies on flavor changes in fragrant rice during storage. RESULTS: Hexanal, nonanal, benzaldehyde, hexadecanoic acid, and methyl ester, were identified as aroma-active compounds in fresh fragrant rice. After storage, more than 100 volatile compounds can be identified. The results indicated that, at high-temperature storage, volatile compounds such as aldehydes, ketones, and furans increased, which led to a deterioration in rice quality. Marker compounds of flavor deterioration, methyl palmitate, 2-methyl-propanoic acid, and 3-hydroxy-2,2,4-trimethylpentyl ester, were determined by principal component analysis. In addition to threonine and proline, the other 14 amino acids contributed to the taste of fragrant rice during storage. Sucrose is the only main contributor to the sweetness of Daohuaxiang 2, whereas glucose and fructose had a little sweet taste contribution during storage. The electronic nose (e-nose) and the electronic tongue (e-tongue) could distinguish samples with different storage conditions. CONCLUSION: Different storage conditions can cause flavor differences in fragrant rice. Especially under high-temperature storage, volatile compounds such as aldehydes, ketones, and furans increase, which is an important reason for the deterioration in the quality of fragrant rice during storage. © 2020 Society of Chemical Industry.

Low-cost modified-atmosphere hermetic storage structures to reduce storage losses of maize (Zea mays L.) cobs and sorghum (Sorghum bicolor L.) heads.

BACKGROUND: Production and marketing of cereal grains are some of the main activities in developing countries to ensure food security. However, the food gap is complicated further by high postharvest loss of grains during storage. This study aimed to compare low-cost modified-atmosphere hermetic storage structures with traditional practice to minimize quantitative and qualitative losses of grains during storage. The study was conducted in two phases: in the first phase, seven hermetic storage structures with or without smoke infusion were compared, and one selected structure was further validated at scaled-up capacity in the second phase. RESULTS: Grains stored in PVC bag-supported structures (with or without smoke infusion) resulted in low live weevil population, low percentage of damaged grains and reduced weight loss with better retention of crude protein and fat contents. Results from validation study also demonstrated that maize and sorghum stored in improved storage structures experienced, respectively, 9.8% and 10.4% weevil damage as compared with 47.3% and 42.3% when stored in traditional storage structures. The same was true in terms of crude protein and fat contents. CONCLUSIONS: The study demonstrated that storage structures supported with PVC bags are efficient and low-cost structures for reducing storage-related losses and supporting food security efforts as compared to traditional methods. Furthermore, the bags can be made locally and with various storage capacities to store either shelled or unshelled products. © 2019 Society of Chemical Industry.

Investigation of diversity and dominance of fungal biota in stored wheat grains from governmental warehouses in West Bengal, India.

BACKGROUND: Fungal infestation is a leading cause of qualitative and quantitative deterioration of stored wheat grains. Limited information is available on the spatial distribution of fungal biota associated with stored wheat grains in India. Fungi were isolated and characterized from nine stored wheat grain samples in three warehouses of the Food Corporation of India, located in three agro-climatic zones (Paschim Medinipur, Bankura and Purulia) of West Bengal in India. RESULTS: Maximum density and fungal diversity were observed in dichloran glycerol agar (DG-18) medium and the number increased with the increase of storage duration. Samples collected from Purulia showed maximum fungal diversity than that from Bankura and Paschim Medinipur. A total of 284 fungal isolates were obtained, classified into 29 operational taxonomic units (based on amplified ribosomal DNA restriction analysis of 18S and internal transcribed spacer sequences), and identified as 24 different fungal species. The majority of fungal isolates belonged to Aspergillus flavus (35%) followed by Rhizopus oryzae (13%) and Eurotium amstelodami (9%). Aspergillopepsin O (PEPO) gene and aflatoxin biosynthetic pathway gene, nor-1, were amplified by polymerase chain reaction (PCR) from 91% and 71% of Aspergillus flavus isolates, respectively, indicating their aflatoxin producing ability. Aflatoxin production was further confirmed by ammonia vapour test, thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC). CONCLUSION: The presence of toxigenic fungi in stored wheat grain emphasizes the necessity of quarantine measures of stored grains before placing them in the public domain to save consumers from health hazards. © 2019 Society of Chemical Industry.

Acacia, cherry and oak wood chips used for a short aging period of rosé wines: effects on general phenolic parameters, volatile composition and sensory profile.

BACKGROUND: There is a restricted knowledge about the potential impact of the use of different wood chip species on the rosé wine aging process. Thus, the aim of this work was to evaluate the general phenolic parameters, aroma composition and sensory profile of rosé wines during a short maturation (20 aging days) in contact with wood chips from oak, acacia and cherry. In addition, the different wood chips were added to a rosé wine without a previous clarification process (unfined wine) and to a rosé wine submitted to a clarification process (fined wine). RESULTS: For the brief maturation time considered, the use of different wood chips induced a tendency for an increase of phenolic content, in particular for unfined rosé wine aged in contact with acacia chips. For volatile composition, the differentiation was clearer for aldehyde compounds group. Regarding sensorial overall appreciation the panel test preferred the unfined rosé wine aged in contact with acacia wood chips. CONCLUSIONS: The results show that, in general, the use of different wood chip species (acacia, cherry and oak) for a brief maturation time of rosé wines could play an important role in rosé wine characteristics, in particular in their phenolic composition. © 2019 Society of Chemical Industry.

Temporal dominance of sensations and preferences of Brazilians and Slovakians: A cross-cultural study of cachaças stored with woods from the Amazon rainforest.

BACKGROUND: Brazilians and Slovakians evaluated the temporal profile and the acceptability of cachaça stored with different woods (Cumarurana (CM), Jatobá (JT) and, Louro-vermelho (LV), which are found in the Amazon rainforest, and also oak), with the aim of performing a cross-cultural comparison of the dynamic profile of the attributes perceived in the cachaças and the sensorial acceptance of the samples. RESULTS: Important differences were observed between the temporal sensorial profiles generated by the two groups and their preferences. Brazilians preferred cachaças stored with the traditional wood, oak, followed by those stored with JT and CM. In contrast, Slovakians preferred cachaças stored with JT, followed by those stored with LV and oak. For both countries, the dominance of wood flavor and vanilla attributes at the end of the analysis time was positively associated with acceptance, while the dominance of off-flavors and the wood flavor attribute at the beginning of the analysis time was negatively associated with acceptance for Brazilians and Slovakians, respectively. CONCLUSION: Brazilians preferred cachaça stored with oak wood, and Slovakians preferred cachaça stored with JT wood, with acceptability being strongly associated with the dominance of wood flavor and vanilla attributes at the end of the evaluation time. © 2018 Society of Chemical Industry.

Effects of storage temperature on bacterial growth rates and community structure in fresh retail sushi.

AIMS: This study was conducted to assess the effects of different storage temperatures (4-20°C), on bacterial concentrations, growth rates and community structure in fresh retail sushi, a popular retail product with a claimed shelf life of 2-3 days. METHODS AND RESULTS: The maximum specific growth rate based on aerobic plate count (APC) at 4°C was 0·06 h-1 and displayed a sixfold increase (0·37 h-1 ) at 20°C. Refrigeration resulted in no growth of hydrogen sulphide (H2 S)-producing bacteria, but this group had the strongest temperature response. The bacterial community structure was determined by PCR/DGGE (denaturing gradient gel electrophoresis). Multivariate analysis based on Bray-Curtis similarities demonstrated that temperature alone was not the major determinant for the bacterial community structure. The total concentration of aerobic bacteria was the variable that most successfully explained the differences between the communities. The dominating organisms, detected by sequencing of DNA bands excised from the DGGE gel, were Brochothrix thermosphacta and genera of lactic acid bacteria (LAB). CONCLUSION: The relationship between growth rates and storage temperatures clearly demonstrates that these products are sensitive to deviations from optimal storage temperature, possibly resulting in loss of quality during shelf life. Regardless of the storage temperature, the bacterial communities converged towards a similar structure and density, but the storage temperature determined how fast the community reached its carrying capacity. SIGNIFICANCE AND IMPACT OF THE STUDY: Little information is available on the microbial composition of ready-to-eat food that are prepared with raw fish, subjected to contamination during handling, and susceptible to microbial growth during cold storage. Moreover, the data are a good first possibility to simulate growth of APC, H2 S-producing bacteria and LAB under different temperature scenarios that might occur during production, distribution or storage.

Glazed clay pottery and lead exposure in Mexico: Current experimental evidence.

OBJECTIVES: Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach. METHODS: We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period. RESULTS AND DISCUSSION: We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats' blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

Lining bunker walls with oxygen barrier film reduces nutrient losses in corn silages.

The objective of this study was to evaluate 2 systems for covering corn silage in bunker silos. The first system consisted of a sheet of 45-µm-thick oxygen barrier film (OB, polyethylene + ethylene-vinyl alcohol) placed along the length of the sidewall before filling. After filling, the excess film was pulled over the wall on top of the silage, and a sheet of polyethylene was placed on top. The second system involved using a standard sheet (ST) of 180-µm-thick polyethylene film. Eight commercial bunker silos were divided into 2 parts lengthwise so that one-half of the silo was covered with OB and the other half with a ST system. During the filling, 3 net bags with chopped corn were buried in the central part (halfway between the top and bottom of the silo) of the bunkers (CCOR) in 3 sections 10 m apart. After filling, 18 net bags (9 per covering system) were buried 40 cm below the top surface of the 3 sections. These bags were placed at 3 distances from the bunker walls (0 to 50 cm, 51 to 100 cm, and 101 to 150 cm). During unloading, the bags were removed from the silos to determine the dry matter (DM) losses, fermentation end products, and nutritive value. The Milk2006 spreadsheet was used to estimate milk per tonne of DM. The model included the fixed effect of treatment (7 different locations in the bunker) and the random effect of the silo. Two contrasts were tested to compare silages in the top laterals (shoulders) with that in the CCOR (CCOR vs. OB and CCOR vs. ST). Three contrasts compared the corresponding distances of the silage covered by the 2 systems (OB50 vs. ST50, OB100 vs. ST100 and OB150 vs. ST150). Variables were analyzed with the PROC MIXED procedure of the SAS at the 5% level. The OB method produced well-fermented silages, which were similar to CCOR, whereas the OB system showed less lactic acid and greater pH and mold counts compared with CCOR. The ST method had 116.2 kg of milk/t less than the CCOR, as the OB system and the CCOR were similar (1,258.3 and 1,294.0 kg/t, respectively). Regarding the distances from the walls, the effects were more pronounced from 0 to 101 cm. The OB50 and OB100 silages had better quality and lower mold counts and DM losses than ST50 and ST100. The OB system reduced DM and nutrient losses at the shoulders in farm bunker corn silages compared with no sidewall plastic. The OB film should lap onto the crop for at least 200 cm so that 150 cm are covered outward from the wall.

Stability of color in Spanish-style green table olives pasteurized and stored in plastic containers.

BACKGROUND: There is an increasing interest in the use of pasteurizable plastic packaging by the olive industry. In order to investigate the change from traditional glass or varnished can containers to plastic packaging, the proper plastic material that is compatible with fermented olives while maintaining color quality during pasteurization treatment and storage must be selected. This work is focused on color stability in two distinct pasteurizable plastic containers with different oxygen permeability. RESULTS: In PET + MDPE/EVOH (polyethylene terephthalate + medium-density polyethylene/ethylene vinyl alcohol) pouches, pasteurization provoked severe browning which drastically decreased their color shelf life (<6 weeks). However, this browning did not occur in the unpasteurized product without preservatives owing to the presence of microorganisms. In AlOx-coated PET + MDPE (aluminum oxide coating on polyethylene terephthalate + medium-density polyethylene) pouches, color changes were small or negligible throughout storage, especially if ascorbic acid was added to the packing solution (shelf life > 6.5 months). CONCLUSION: The plastic material had a significant effect on the retention of color of the pasteurized product. The use of AlOx-coated PET + MDPE pouches could be an alternative to traditional packaging for the pasteurization and storage of Spanish-style green olives from a color quality standpoint. © 2017 Society of Chemical Industry.

Fate of mesophilic aerobic bacteria and Salmonella enterica on the surface of eggs as affected by chicken feces, storage temperature, and relative humidity.

We compared the microbiological quality of chicken eggshells obtained from a traditional wholesale market and a modern supermarket. We also determined the survival and growth characteristics of naturally occurring mesophilic aerobic bacteria (MAB) and artificially inoculated Salmonella enterica on eggshells under various environmental conditions (presence of chicken feces, temperature [4, 12, or 25 °C], and relative humidity [RH; 43 or 85%]). The populations of MAB, coliforms, and molds and yeasts on eggshells purchased from a traditional wholesale market were significantly (P ≤ 0.05) higher than those from a modern supermarket. In the second study, when we stored uninoculated eggs under various storage conditions, the population of MAB on eggshells (4.7-4.9 log CFU/egg) remained constant for 21 days, regardless of storage conditions. However, when eggshells were inoculated with S. enterica and stored under the same conditions, populations of the pathogen decreased significantly (P ≤ 0.05) under all tested conditions. Survival of S. enterica increased significantly (P ≤ 0.05) in the presence of feces, at low temperatures, and at low RH. These observations will be of value when predicting the behavior of microorganisms on eggshells and selecting storage conditions that reduce the populations of S. enterica on eggshells during distribution.

Triple-Layer Plastic Bags Protect Dry Common Beans (Phaseolus vulgaris) Against Damage by Acanthoscelides obtectus (Coleoptera: Chrysomelidae) During Storage.

Fumigated dry common beans (Phaseolus vulgaris L.) that were artificially infested with Acanthoscelides obtectus Say, and others that were not artificially infested, were stored in hermetic triple-layer PICS (Lela Agro, Kano, Nigeria) or woven polypropylene (PP) bags for 6 mo at ambient laboratory temperature conditions of 22.6 ± 1.9°C and 60.1 ± 4.3% relative humidity. In an additional trial, beans contained in PP bags were treated with Actellic Super dust before introducing A. obtectus. Moisture content, number of live adult A. obtectus, seed damage, weight loss, and seed germination were determined at monthly intervals. At 6 mo, beans stored in PICS bags retained higher moisture than those stored in PP bags, but in all treatments the moisture level remained below that recommended for safe storage of beans. In the PICS bags, proliferation of A. obtectus did not proceed and at 6 mo, beans stored in these bags did not have insect-inflicted seed damage or weight loss. In contrast, seed damage and weight loss in PP bags exceeded economic threshold after 1 mo in the absence of Actellic Super dust (Syngenta Crop protection AG, Basle, Switzerland), and after 2 mo in the presence of it. Germination of beans stored in PP bags decreased greatly whereas the beans stored in PICS bags did not show reduced germination. Chemical free storage of common beans in PICS bags protects them against damage by A. obtectus.

Role of initial contamination levels, biofilm maturity and presence of salt and fat on desiccation survival of Listeria monocytogenes on stainless steel surfaces.

This study investigated the effect of initial contamination levels, biofilm maturity and presence of salt and fatty food soils on desiccation survival of Listeria monocytogenes on stainless steel (SS) coupons. L. monocytogenes cultures grown (at 15 °C for 48 h) in Tryptic Soy Broth with 1% glucose (TSB-glu) containing either 0.5 or 5% (w/v) NaCl were re-suspended in TSB-glu containing either 0.5 or 5% NaCl and used to contaminate SS coupons at levels of 3.5, 5.5, and 7.5 log CFU/cm². Desiccation (at 15 °C for 20 days, 43% RH) commenced immediately (non-biofilm) or following biofilm formation (at 15 °C for 48 h, 100% RH). To study the impact of food lipids, non-biofilm L. monocytogenes cells were suspended in TSB-glu containing either canola oil (5-10%) or lard (20-60%) and desiccated as above on SS coupons. Following desiccation for 20 days, survivors decreased by 1.4-3.7 log CFU/cm² for non-biofilm L. monocytogenes cells. The contamination level had no significant (p > 0.05) effect on survival kinetics. SEM micrographs showed mature biofilms on coupons initially contaminated with 5.5 and 7.5 log CFU/cm². Mature biofilm cells were significantly (p < 0.05) more desiccation resistant than cells in immature biofilms formed by the lowest contamination level. Besides biofilm maturity/formation, previous osmoadaptation, exposure to lard (20-60%) or salt (5%) during desiccation significantly (p < 0.05) increased the bacterium's survival. In conclusion, L. monocytogenes desiccation survival can be greatly reduced by preventing presence of mature biofilms and salty or fatty soils on food contact surfaces.

Migration of substances from food contact plastic materials into foodstuff and their implications for human exposure.

The safety of food contact plastic materials, including PP, PE, PET, PCT, PLA, PBT and cross-linked polyester, was assessed with regard to migrated substances. The migrated concentrations of overall migrants (OMs), terephthalic acid, acetaldehyde, 1,4-butanediol and lead, were determined according to the standards and specifications for utensils, containers and packages in Korea. Food simulants of 4% acetic acid, water and n-heptane were used for the analysis of the substances. The dietary exposures of terephthalic acid, acetaldehyde and 1,4-butanediol were assessed using the dietary concentrations and the food consumption data. As a result, the dietary exposures were considered to be safe comparing to the health-based guidance values. In the case of lead, the margin of exposure (MOE) approach was applied. The MOEs calculated using the UB concentration and mean consumption data were ranged from 3 to 1000, which indicated low concern for health risk. Moreover, in this study, the dietary exposures were estimated by the Korean MFDS and U.S. FDA methods, respectively. As a result, the assessed risks were considered to be low in both cases. Based on the results of current exposure assessments, it could be considered that the food contact plastic materials are properly controlled by the regulatory authorities.