DIRECT PLATING: A METHOD FOR DETECTING FUNGAL CONTAMINATION IN PAPERBOARD CARTONS

Contamination of refrigerated juice products in gable-top cartons can occur by filamentous fungi that are present in the paperboard. A method was developed to assay the mycoflora of paperboard carton material used in beverage packaging. This method involved direct plating on an agar surface of 1 cm² carton pieces rather than disintegration of carton material in a blender prior to plating. When compared to the standard disintegration method traditionally used for monitoring contamination of paperboard, the new method is less cumbersome, more efficient, and reduces opportunities for contamination. The number of colonies produced by the direct plating method was greater than or equal to the modified standard disintegration method. Direct plating also resulted in a larger number of different genera isolated.     

LABORATORY EVALUATION OF PAPERBOARD CARTONS FOR THE NONREFRIGERATED STORAGE OF STERILIZED MILK1,2

The suitability of various carton materials for the nonrefrigerated storage of sterilized milk was investigated. One quart paperboard cartons were fabricated from the same base sheet of stock but varied in the type of sizing used to make them resistant to penetration by liquids and whether or not they were aluminum foil-lined. They were preformed and sterilized with ethylene oxide. The four types of paperboard were: (a) rosin (sizing) paperboard (R); (b) rosin paperboard with foil lining (RF); (c) cyanasize (sizing) juice paperboard (CJ); and (d) cyanasizejuice paperboard with foil lining (CJF). Each carton was aseptically filled and sealed, in a glovebox. Incubation was carried out at 20°C for up to nine weeks. Every week five cartons of each type were randomly selected and the milk tested for microbial stability and flavor. The candidate cartons were also tested for degradation of the physical characteristics of static bulge, wicking, tensile strength, and stiffness. Of these, it appears as if selection of carton type will be determined mostly by wicking resistance. The most acceptable carton type is CJF, which had minimal wicking, acceptable bulge, acceptable stiffness, and acceptable tensile strength during the testing period.     

EFFECT OF PACKAGING MATERIALS ON COLOR,VITAMIN C AND SENSORY QUALITY OF REFRIGERATED MANDARIN JUICE

ABSTRACT

Refrigerated mandarin juice was packed in four different containers, three cartons with different composition and one polyethylene terephthalate transparent bottle, and was stored at 4C for 90 days. During the storage of these juices, changes in the headspace gas composition, vitamin C, and CIE L*, a* and b* color coordinates were evaluated. In addition, a consumer panel evaluated the sensory color, fresh mandarin flavor and presence of off‐flavors in the juices. Experimental data indicated that the deterioration of mandarin juices (ascorbic acid degradation and darkening of color) was triggered by the rise in oxygen in the headspace of the storage containers. The type of container played a predominant role in determining the juice quality, with carton containers with an inner layer of aluminum foil providing the juices with the best quality throughout their storage.

PRACTICAL APPLICATIONS

Results from this study will provide manufacturers of mandarin juice with information dealing with the storage and quality of juices packed in different containers. In this way, if manufacturers want to use transparent polyethylene terephthalate (PET) bottles showing the color and appearance of the juice, they will be aware that the shelf life of the juice will be much shorter than in packed cartons; this reduction will be from more than 90 to 36 days (PET bottle). On the other hand, if manufacturers want to use carton for their packaging, they will be aware that using a container with a thick inner layer of aluminum foil will maintain the quality of the juice for a longer time (over 90 days) compared with a shelf life of about 54 days from cartons with an inner layer of ethylene vinyl alcohol copolymers.     

Characterization of Osmotolerant Yeasts and Yeast‐Like Molds from Apple Orchards and Apple Juice Processing Plants in China and Investigation of Their Spoilage Potential

Yeasts and yeast‐like fungal isolates were recovered from apple orchards and apple juice processing plants located in the Shaanxi province of China. The strains were evaluated for osmotolerance by growing them in 50% (w/v) glucose. Of the strains tested, 66 were positive for osmotolerance and were subsequently identified by 26S or 5.8S‐ITS ribosomal RNA (rRNA) gene sequencing. Physiological tests and RAPD‐PCR analysis were performed to reveal the polymorphism of isolates belonging to the same species. Further, the spoilage potential of the 66 isolates was determining by evaluating their growth in 50% to 70% (w/v) glucose and measuring gas generation in 50% (w/v) glucose. Thirteen osmotolerant isolates representing 9 species were obtained from 10 apple orchards and 53 target isolates representing 19 species were recovered from 2 apple juice processing plants. In total, members of 14 genera and 23 species of osmotolerant isolates including yeast‐like molds were recovered from all sources. The commonly recovered osmotolerant isolates belonged to Kluyveromyces marxianus, Hanseniaspora uvarum, Saccharomyces cerevisiae, Zygosaccharomyces rouxii, Candida tropicalis, and Pichia kudriavzevii. The polymorphism of isolates belonging to the same species was limited to 1 to 3 biotypes. The majority of species were capable of growing within a range of glucose concentration, similar to sugar concentrations found in apple juice products with a lag phase from 96 to 192 h. Overall, Z. rouxii was particularly the most tolerant to high glucose concentration with the shortest lag phase of 48 h in 70% (w/v) glucose and the fastest gas generation rate in 50% (w/v) glucose.     

CONTAMINATION OF GRAINS BY MYCOTOXIN-PRODUCING MOLDS AND MYCOTOXINS AND CONTROL BY GAMMA IRRADIATION

Ninety random grain samples were collected and analyzed for mycotoxins, and the effect of gamma irradiation on the production of mycotoxins in grains was studied. Aspergillus, Penicillium, Mucor, Rhizopus, Fusarium, Alternaria, Scopulariopsis and Cladosporium were the most common fungal genera isolated from grains. Aspergillus flavus, Aspergillus niger, Aspergillus candidus, Aspergillus ochraceus, Penicillium citrinum, Penicillium expansum, Penicillium citreonigrum, Penicillium purpurogenum, Penicillium griseofulvum and Penicillium verrucosumwere the most common Aspergillus and Penicillium species in grains. Out of 120 Aspergillus and Penicillium isolates, 80 were mycotoxin producers. Analysis of grains revealed the occurrence of aflatoxin B₁ ochratoxin A, cycolopiazonic acid and citrinin. Of the 90 samples, 67 were positive for one or more mycotoxin. Irradiation of grains at dose of 2.0 and 4.0 kGy decreased significantly the total fungal counts compared with unirradiated controls. After 100 days of storage at room temperature, the unirradiated grains were contaminated with high concentrations of mycotoxins as compared with irradiated 4.0‐kGy samples. Mycotoxin production in grains decreased with increasing irradiation doses and was not detected at 6.0 kGy over 100 days of storage.     

Fungi associated with post-harvest rot of sweet orange (Citrus sinensis) and aflatoxin B1 production by isolates of Aspergillus flavus on plain and supplemented orange juice

Samples of rotting sweet orange (Citrus sinensis) were obtained from the depots, sales counters and waste baskets. Fungi associated with rotting fruits were isolated and identified. Out of 12 species of fungi isolated, 8 are known to be producers of toxins. The 7 isolates of Aspergillus flavus obtained were screened for aflatoxin production in a nutrient solution, and 4 were found to be aflatoxigenic, producing primarily aflatoxin B₁. Aflatoxin B₁ production of the toxigenic isolates were further studied on plain juice and juice separately supplemented with 2.0% yeast extract and 2.0% sucrose. The highest yield of aflatoxin B₁ was produced on juice supplemented with yeast extract by the 4 toxigenic A. flavus isolates, followed by sucrose supplementation while the lowest amount of aflatoxin B₁ was detected on plain juice. Optimum temperature for aflatoxin B₁ production by A. flavus isolate (IBA-O1) was 25 °C to 30 °C, for an incubation period of 7–11 days on plain and supplemented juice media.     

Migration studies of 3-chloro-1,2-propanediol (3-MCPD) in polyethylene extrusion-coated paperboard food packaging

The manufacturing process of paperboard food packaging can produce small quantities of 3-chloro-1,2-propanediol (3-MCPD or 3-monochloropropane-1,2-diol) when wet-strength resins containing epichlorohydrin are used. 3-MCPD is from the same family as 1,3-dichloro-2-propanol (1,3-DCP), which is known to cause cancer in animals. 3-MCPD has been found in acid hydrolyzed vegetable protein, Asian sauces and paperboard for food contact. In this investigation, we conducted extraction studies to measure 3-MCPD migration into food simulant solvents from the food contact side of polyethylene extrusion-coated paperboard beverage cartons and aqueous extractions of cut pieces from the entire paperboard. We demonstrate that 3-MCPD confirmed present at concentrations up to 9.9 mg kg^?1 within the paperboard matrix does not migrate through the polyethylene-coated food contact surface. The aqueous extraction of the entire paperboard and food contact side extractions with aqueous/acidic food simulants were performed using US Food and Drug Administration (FDA) and European Commission (EU) migration testing protocols. We also show that no significant amount of 3-MCPD migrates through the unskived edges on the inside seam of the paperboard structure. The methodology for the aqueous and migration cell extractions using GC–MS analyses was validated with a limit of quantification (LOQ) of 0.009 mg kg^?1 and a limit of detection (LOD) of 0.005 mg kg^?1.     

Occurrence of toxigenic fungi in ochratoxin A contaminated liquorice root

Fungi associated with ochratoxin A (OTA)-contaminated liquorice root and their capabilities for OTA production were investigated. Medicinal materials of mouldy liquorice root were collected from herbal markets located in Jiangxi, Zhejiang, Henan provinces and Beijing, China, respectively. Sixteen fungal species belonging to Penicillium, Aspergillus, Eurotium, Fusarium, Mucor and Scopulariopsis were isolated; the fungal composition was different in each liquorice root sample. Penicillium polonicum was predominant, comprising 54% of the total isolates in the liquorice root sample from Jiangxi province, which was contaminated with OTA at the highest level. In other samples with lower OTA contents, species of Aspergillus and Eurotium were predominant. OTA production of representative strains on rice media was detected by LC-MS/MS; all Penicillium polonicum isolates and a P. chrysogenum were ochratoxigenic; OTA concentrations ranged from 6.94 to 217.37?ng?g^?1. This is the first study to report P. polonicum as an OTA-producing fungus. OTA contamination of mouldy liquorice root constitutes a major health hazard in consumption. This situation demands urgent and undivided attention.     

Toxigenic penicillia spoiling frozen chicken nuggets

Frozen chicken nuggets are classified as pre-prepared frozen meals. These products are convenient to consumers as they are easy to prepare and allow for long storage by freezing. Over the years, spoilage of frozen food products caused by fungi has been a continual problem for the food industry since mold can develop when frozen foods are allowed to attain temperatures of − 10 °C, or above. The growth of fungi on the food surface results in economic losses and represents a hazard to public health due to the possibility of mycotoxin production. The aim of this study was to identify the species of filamentous fungi involved in the spoilage of frozen chicken nuggets and determine their ability to produce mycotoxins under laboratorial conditions. A total of 7 samples of frozen chicken nuggets were analyzed by dilution plating in potato dextrose agar (PDA). These products had been returned by customers due to visible mold growth on their surface. The predominant species found were Penicillium glabrum, Penicillium polonicum, Penicillium manginii, Penicillium crustosum, Penicillium commune, and Penicillium solitum. Analysis of the profile of secondary metabolites was carried out in HPLC after growing the isolates in Czapek yeast autolysate agar (CYA) and yeast extract agar and sucrose (YESA) and extracting the extrolites with a solution of ethyl acetate, dichloromethane, methanol, and formic acid. Some isolates of these species showed an ability to synthesize mycotoxins such as cyclopiazonic acid citreoviridin, roquefortine C, penitrem A, and verrucosidin under standard conditions. Considering the occurrence of fungal spoilage in frozen food and the potential hazard involved, more studies on psychrophilic fungi growth in foods stored at low temperatures are necessary.     

Evaluation of several culture media for production of patulin by Penicillium species

The aim of this study was to evaluate different species of Penicillium to identify those which have the potential to produce the greatest amount of the mycotoxin, patulin. Additionally, six different culture media were compared to determine maximum patulin production. Eleven different strains of Penicillium species were selected because they had previously been reported to be producers of patulin. The strains included Penicillium expansum, Penicillium griseofulvum (formerly Penicillium urticae), Penicillium clavigerum, and Penicillium coprobium and a recent Penicillium sp. isolated from an apple. Cultures were grown in duplicate in three different liquid media: potato dextrose, malt extract, and glucose/yeast extract/peptone, both with and without manganese supplementation. Patulin production was compared at 24, 48, 72, and 96 h. Variability in patulin production occurred among the different species, growth media used, and time of incubation. All three of the P. griseofulvum isolates were the highest producers of patulin at 96 h. For most of the strains, potato dextrose broth supplemented with manganese was optimal for maximum production of patulin. Although P. expansum is frequently cited as the most likely source of patulin in apple juice, certain other Penicillium species are capable of producing more patulin than strains of P. expansum. The apple juice industry should be alert to the possibility that Penicillium species other than P. expansum can be responsible for the occurrence of patulin.     

The mycobiota of three dry-cured meat products from Slovenia

The surface mycobiota of three types of Slovenian dry-cured meat products were isolated from a total of 75 items of product that were sampled periodically during the drying/ripening stage of processing. The predominant filamentous fungal genus isolated was Penicillium. Eurotium spp., Aspergillus versicolor and Cladosporium spp. were isolated from only two of the products. Eight Penicillium species were identified. Penicillium nordicum was recovered frequently. Penicillium nalgiovense was recovered less frequently, from one product only (a salami), while a yet-to-be described species Penicillium “milanense” was isolated from 21 items. The other penicillia were rarely isolated. Of the isolated and identified species, those that can produce mycotoxins are: A. versicolor, Penicillium brevicompactum, Penicillium chrysogenum, P. nordicum, and Penicillium polonicum. Their growth on dry-cured meat products is undesirable.     

Contamination of freshly harvested Bambara groundnut (Vigna subterranea) seed from Mpumalanga,South Africa,with mycotoxigenic fungi

Freshly harvested Bambara groundnut (BGN) is occasionally consumed raw and can potentially become infected with mycotoxingenic field fungi. In this study, BGN samples were obtained from 12 farms in three districts of Mpumalanga in South Africa. Eight pooled samples were screened for multi-mycotoxin contamination using Ultra Performance Liquid-Chromatography tandem mass spectrometry (UPLC-MS/MS). To identify mycoflora, 12 samples were screened using conventional and molecular methods. Selected potential mycotoxin producing isolates were screened for mycotoxins using UPLC-MS/MS. No mycotoxins were detected on the freshly harvested BGN samples, but they were infected with various mycotoxin producing fungal species namely Aspergillus flavus (50%), Penicillium citrinum (25%), Penicillium oxalicum (17%), Penicillium citreoviridin (0.8%), and Fusarium verticillioides (0.8%). Following screening of selected fungal cultures, aflatoxin B₁ (0.4, 0.45 and 0.4 ppm) and fumonisin B₁ (0.7 ppm) were detected from A. flavus and F. verticillioides, respectively. Identification of mycotoxigenic fungi on freshly harvested BGN presents a potential health risk.     

Distribution of Penicillium commune isolates in cheese dairies mapped using secondary metabolite profiles, morphotypes, RAPD and AFLP fingerprinting

In an 8-year study of the diversity and distribution of Penicillium commune contaminants in two different cheese dairies, swab and air samples were taken from the production plants, the processing environment and contaminated cheeses. A total of 321 Penicillium commune isolates were characterized using morphotypes (colony morphology and colours) and secondary metabolite profiles. Based on production of secondary metabolites the P. commune isolates were classified into 6 groups. The genetic diversity of the P. commune isolates was assessed using randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP). For a sub-set of 272 P. commune isolates RAPD analysis generated 33 RAPD groups whereas AFLP profiling revealed 55 AFLP groups. This study conclusively showed that the discriminatory power of AFLP was high compared to RAPD and that AFLP fingerprinting matched morphotyping. P. commune isolates with identical profiles using all four typing techniques were interpreted as closely related isolates with a common origin and the distribution of these isolates in the processing environment indicated possible contamination points in the cheese dairies. The coating process and unpacking of cheeses with growth of P. commune seemed to cause the contamination problems. Several identical P. commune isolates remained present in the processing environment for more than 7 years in both dairies.     

Properties of Bacillus cereus and other bacilli contaminating biomaterial-based industrial processes

This paper is an overview on bacilli in industrial processes, with focus on food grade paper and paperboard production. Paperboards mainly contain sporeforming bacteria belonging to the genera Bacillus, Paenibacillus and Brevibacillus, usually found in quantities from <50 to 250 cfu g⁻¹ homogenized paperboard. Of those frequently found, Bacillus cereus group, B. licheniformis, B. subtilis and Brevibacillus brevis are important for food hygiene because of their hydrolytic activities on food components and the ability of some strains to produce food poisoning toxins or to grow at refrigerated temperatures. We found that the phenotypic properties (lecithinase activity, nitrate reduction) used in standard methods (e.g., ISO, FDA, IDF) to recognize B. cereus, were unreliable for industrial isolates. Whole cell fatty acid composition of a group of the industrial isolates deviated so much from those in a widely used commercial database that the strains were not or only poorly recognized as B. cereus. Industrial isolates, including toxigenic ones, often missed one or more of these characters, even in cases where 100% 16S rDNA identity was found with B. cereus or with B. thuringiensis. 11-Methyldodecanoic acid and trans-9-hexadecenoic acid were found without exception in over 200 industrial B. cereus group isolates and in over 30 culture collection strains. The detection of these fatty acids is a secure method for the identification of B. cereus. Negative reaction for starch hydrolysis and for BCET-RPLA test and a specific ribotype were found in all B. cereus strains producing the emetic toxin.     

Phylogenetic and spectroscopic analysis of Alicyclobacillus isolates by 16S rDNA sequencing and mid-infrared spectroscopy

Alicyclobacillus spp. are a group of thermophilic, acidophilic, spore-forming bacteria, some of which cause spoilage in commercially pasteurized fruit and vegetable juice products including apple, orange, tomato and carrot juice. In this study, we characterized seven isolates of Alicyclobacillus (14-2, KF, A-Gala 2-1, C-Fuji 6, Gala 9-2, 1016, 18-1) and a reference strain A. acidiphilus DSM 14558 by a 16S rDNA sequencing technique and Fourier transform infrared (FT-IR) spectral features. The degree of similarity between Alicyclobacillus isolates based upon phylogenetic analysis of sequence data and multivariate statistical analysis of FT-IR spectral data was determined. Results from both methods were consistent, suggesting that a combination of methods targeting both 16S rDNA and mid-infrared spectroscopic signatures may be a suitable and more accurate approach to either identify or discriminate Alicyclobacillus isolates from fruit and vegetable juice products.     

新型包装技术——纸板封盖

<正> 配备有纸板封盖的圆柱体或非圆柱体纸筒,采用全纸板材料包装,使用方便,而且成本低,可与折叠式纸盒或组合罐相媲美。完整的双切痕纸板盖开启便利和可靠,配备有防盗拉链条或拉条。产品的提取方便快捷,并能完好地保护产品。     

The diversity and evolution of microbiota in traditional Turkish Divle Cave cheese during ripening

The microbial diversity of traditional Turkish Divle Cave cheese was evaluated in three independent batches. Using molecular techniques, twenty three bacterial species were identified in the interior and outer part of the cheese on days 60 and 120. Bacilli and Gammaproteobacteria classes were predominant during early stages of ripening and Actinobacteria at later stages. Nineteen species of filamentous fungi and five yeast species were identified and the most frequently isolated species were Penicillium polonicum, Penicillium biforme, Penicillium roqueforti, Penicillium chrysogenum and Debaryomyces hansenii. The microbiota displayed similar communities among batches, but high diversity in different parts of the cheese during ripening. Novel cheese starter cultures could be developed after the technological characterisation of the isolated strains.     

Chemical Characterization of Tomato Juice Fermented with Bifidobacteria

Abstract: The objective of this research was to characterize the chemical properties of tomato juice fermented with bifidobacterial species. Tomato juice was prepared from fresh tomatoes and heated at 100 °C prior to fermentation. Bifidobacterium breve, Bifidobacterium longum, and Bifidobacterium infantis were inoculated in tomato juice and kept at 35 to 37 °C for up to 6 h. Fructooligosaccharide (FOS) was added to tomato juice prior to fermentation. The analyses for brix, total titratable acidity (TTA), pH, color, and lycopene content were conducted to characterize tomato juices fermented with bifidobacterial species. Heat treatment of tomato juice did not cause any significant changes in brix, pH, and TTA. Only the redness of tomato juice was significantly increased, as the heating time increased to 30 min. The tomato juices fermented with B. breve and B. longum exhibited significant decreases in pH (3.51 and 3.80, respectively) and significant increases in TTA (13.50 and 12.50, respectively) (P < 0.05). B. infantis did not cause any significant change in the chemical properties of tomato juice. The addition of FOS further improved the fermentation of tomato juice by bifidobacterial species. The lycopene contents of tomato juice were significantly increased from 88 to 113 μg/g by heat treatment at 100 °C (P < 0.05), however did not exhibit any significant change after fermentation with bifidobacterial species.     

Discrimination between Bacillus and Alicyclobacillus Isolates in Apple Juice by Fourier Transform Infrared Spectroscopy and Multivariate Analysis

Alicyclobacillus is a causative agent of spoilage in pasteurized and heat‐treated apple juice products. Differentiating between this genus and the closely related Bacillus is crucially important. In this study, Fourier transform infrared spectroscopy (FT‐IR) was used to identify and discriminate between 4 Alicyclobacillus strains and 4 Bacillus isolates inoculated individually into apple juice. Loading plots over the range of 1350 and 1700 cm^?1 reflected the most distinctive biochemical features of Bacillus and Alicyclobacillus. Multivariate statistical methods (for example, principal component analysis and soft independent modeling of class analogy) were used to analyze the spectral data. Distinctive separation of spectral samples was observed. This study demonstrates that FT‐IR spectroscopy in combination with multivariate analysis could serve as a rapid and effective tool for fruit juice industry to differentiate between Bacillus and Alicyclobacillus and to distinguish between species belonging to these 2 genera.