Country Cured Ham as a Possible Source of Aflatoxin

Of 10 fungi isolated from a heavily molded country cured ham, 4 were identified as toxigenic strains of Aspergillus flavus.     

Acute Toxicity of Ochratoxins A and B in Chicks

Ochratoxins A and B were given to 1-day-old Babcock B-300 cockerels to evaluate acute toxic effects. Two trials with ochratoxin A gave 7-day oral median lethal dose estimates of 116 mug (3.3 mg/kg) and 135 mug (3.9 mg/kg) per chick. Chicks given daily oral doses of 100 mug of ochratoxin A died on the second day. Single subcutaneous doses of 400 mug of ochratoxin A were also lethal. The 7-day oral median lethal dose of B was estimated at 1,890 mug (54 mg/kg) per chick. Chicks given oral doses of 100 mug of ochratoxin B daily for 10 days survived. Sublethal doses of both ochratoxins A and B resulted in growth suppression which was proportional to the amount of ochratoxin given. Visceral gout was the principal gross finding. Microscopic examinations revealed acute nephrosis, hepatic degeneration or focal necrosis, and enteritis. Suppression of hematopoiesis in the bone marrow and depletion of lymphoid elements from the spleen and bursa of Fabricius were frequently seen. Both ochratoxins appeared to have similar pathological effects. This is the first report on the toxicity of ochratoxin B.     

Identification and Aflatoxin Production of Molds Isolated from Country Cured Hams

Of 562 molds isolated from country cured hams, 403 isolates were of the genus Penicillium, 121 were Aspergillus, and 36 were Cladosporium, Alternaria, and other genera.     

Production of Ochratoxins in Different Cereal Products by Aspergillus ochraceus

The effects of temperature and length of incubation on ochratoxin A production in various substrates were studied. The optimal temperature for toxin production by Aspergillus ochraceus NRRL-3174 was found to be around 28 C. Very low levels of ochratoxin A are produced in corn, rice, and wheat bran at 4 C. The optimal time for ochratoxin A production depends on the substrate, ranging from 7 to 14 days at 28 C. Ochratoxin B and dihydroisocoumaric acid, i.e., one of the hydrolysis products of ochratoxin A, were produced in rice but at levels considerably lower than ochratoxin A. No ochratoxin C was produced in rice at 28 C. When added to rice cereal or oatmeal, the toxin was found to be very stable over prolonged storage and even to autoclaving for 3 hr.     

Aflatoxin Production in Meats. II. Aged Dry Salamis and Aged Country Cured Hams

Italian-type salamis contaminated with Aspergillus flavus were more likely to develop aflatoxins during aging than were smoked Hungarian-type salamis under the same conditions. Temperatures below 15 C and humidities of less than 75% were found to prevent aflatoxin development during the aging of salami. The aging of salami for 8 weeks and the presence of curing ingredients, especially pepper and sodium nitrite, tended to reduce the amounts of aflatoxins found. Aflatoxins were produced by A. flavus and A. parasiticus on 6- to 9-month-old country cured hams during aging when the temperature approached 30 C.     

Radiation Sterilization of Prototype Military Foods: II. Cured Ham

Ten lots of diced cured ham, packed in cans, were inoculated with approximately 10(6)Clostridium botulinum spores per can. Each lot was seeded with a different strain (five type A and five type B strains). All cans were irradiated to various dose levels with Co(60). Evidence provided by swelling, toxicity, and recoverable C. botulinum with 6,350 cans demonstrated that: (i) 4.5 Mrad was more than adequate as a sterilization dose; (ii) the minimal experimental sterilizing dose (ESD) based on nonswollen nontoxic endpoints was 2.0 < ESD 相似文献   

Potential Production of Sterigmatocystin on Country-Cured Ham

In laboratory media, 10 of 16 isolates of Aspergillus versicolor from country-cured ham were capable of producing sterigmatocystin. Three of these isolates were tested and found to produce sterigmatocystin on country-cured ham after 14 days of incubation at 20 or 28 C.     

Production of Citrinin by Penicillium viridicatum on Country-Cured Ham

Seven strains of Penicillium viridicatum isolated from country-cured ham produced citrinin in potato dextrose broth and on country-cured ham. None of the strains produced detectable amounts of citrinin at 10 C. The optimal temperature range for citrinin production was 25 to 30 C.     

Processing-Dependent and Clonal Contamination Patterns of Listeria monocytogenes in the Cured Ham Food Chain Revealed by Genetic Analysis

The quantitative and qualitative patterns of environmental contamination by Listeria monocytogenes were investigated in the production chain of dry-cured Parma ham. Standard arrays of surfaces were sampled in processing facilities during a single visit per plant in the three compartments of the food chain, i.e., ham production (19 plants) and postproduction, which was divided into deboning (43 plants) and slicing (25 plants) steps. The numbers of sampled surfaces were 384 in ham production, with 25 positive for L. monocytogenes, and 1,084 in postproduction, with 83 positives. Statistical analysis of the prevalence of contaminated surfaces showed that in ham production, contamination was higher at the beginning of processing and declined significantly toward the end, while in postproduction, prevalence rose toward the end of processing. Prevalence was higher in the deboning facilities than in slicing facilities and was dependent on the type of surface (floor/drainage > clothing > equipment). The qualitative pattern of contamination was investigated through an analysis of the survey isolates and a set of isolates derived from routine monitoring, including longitudinal isolations. Pulsed-field gel electrophoresis (PFGE) and whole-genome single-nucleotide polymorphism (SNP) analysis revealed a remarkable clonality of L. monocytogenes within plants, with the detection of 16 plant-specific clones out of 17 establishments with multiple isolates. Repeated detections of clonal isolates >6 months apart were also observed. Six was the maximum number of between-isolate differences in core SNPs observed within these clones. Based on the same six-SNP threshold, three clusters of clonal isolates, shared by six establishments, were also identified. The spread of L. monocytogenes within and between plants, as indicated by its clonal behavior, is a matter of concern for the hygienic management of establishments.     

Disfiguring Mucor irregularis Infection Cured by Amphotericin B and Itraconazole: A Case Report and Treatment Experience

Mycopathologia - We report a case of primary cutaneous mucormycosis caused by Mucor irregularis. A 52-year-old male farmer was presented to our hospital with a history of progressive nodule and...     

Production of cyclodepsipeptides destruxin A and B from Metarhizium anisopliae

Maltose and peptone were the best carbon and nitrogen sources for the production of destruxins from Metarhizium anisopliae. With the addition of 0.1% (w/v) beta-alanine to the basal medium, the yields of cyclodepsipeptides DA and DB were 7.2 and 279 mg/L, respectively, which was 2-fold higher than that of control experiment. Response surface methodology (RSM) was applied to optimize the compositions of maltose, peptone, beta-alanine, and glucose used in a shaker-flask cultivation of M. anisopliae for the production of DA and DB. Estimated optimal compositions for the DA production were maltose 2.58%, peptone 0.72%, beta-alanine 0.02%, and glucose 0.55%. The predicted DA yield was 18.5 mg/L. On the other hand, the optimal compositions for DB production were maltose 2.51%, peptone 0.75%, beta-alanine 0.02%, and glucose 0.43%. A maximum DB yield of 232 mg/L was predicted. These were confirmed by cultivation experiments conducted at the optimized conditions for maximum destruxins production in a shaker-flask. Furthermore, a modest high level of DA (49 mg/L) and DB (268 mg/L) yields were obtained by employing the response surface methodology optimized DB production medium in a no-baffle, stirred-tank fermentor.     

Effect of Nitrite and Nitrate on Toxin Production by Clostridium botulinum and on Nitrosamine Formation in Perishable Canned Comminuted Cured Meat

[This corrects the article on p. 357 in vol. 25.].     

Effect of Nitrite and Nitrate on Toxin Production by Clostridium botulinum and on Nitrosamine Formation in Perishable Canned Comminuted Cured Meat

Comminuted ham was formulated with different levels of sodium nitrite and nitrate, inoculated with Clostridium botulinum, and pasteurized to an internal temperature of 68.5 C. When added to the meat, nitrite concentrations decreased, and cooking had little effect on them. Nitrite concentrations decreased more rapidly during storage at 27 than at 7 C; however they remained rather constant at formulated levels throughout the experiment at both incubation temperatures. The level of nitrite added to the meat greatly influenced growth and toxin production of C. botulinum. The concentration of nitrite necessary to effect complete inhibition was dependent on the inoculum level. With 90 C. botulinum spores/g of meat, botulinum toxin developed in samples formulated with 150 but not with 200 mug of nitrite per g of meat. At a spore level of 5,000/g, toxin was detected in samples with 400 but not with 500 mug of nitrite per g of the product incubated at 27 C. At lower concentrations of nitrite, growth was retarded at both spore levels. No toxin developed in samples incubated at 7 C. Nitrate showed a statistically significant inhibitory effect at a given nitrite level; however, the effect was insufficient to be of practical value. Analyses for 14 volatile nitrosamines from samples made with varying levels of nitrite and nitrate were negative at a detection level of 0.01 mug of nitrite or nitrate per g of meat.     

Mucor irregularis Infection Around the Inner Canthus Cured by Amphotericin B: A Case Report and Review of Published Literatures

We report a case of primary cutaneous mucormycosis caused by Mucor irregularis. A 47-year-old farmer was presented to our clinic with the history of progressive red plaque around the inner canthus following dacryocystectomy about a year earlier. Linear, aseptate hyphae were seen by direct KOH examination and in biopsy. Fungal culture revealed light yellow filamentous colonies that were identified as Mucor irregularis by nucleotide sequencing of rRNA gene. Amphotericin B and dexamethasone were used in gradually increasing dosage. The treatment lasted 43 days, and the patient received 760 mg total amphotericin B. The patient was discharged after 2 months of treatment. The plaque became smooth, and fungal culture was negative. There was no recurrence for half a year through telephone follow-ups. A review of published studies revealed 23 cases of Mucor irregularis infection. Most cases resulted following injuries or surgical complications. Farmers and manual laborers were most at risk with males outnumbering females among patients. Amphotericin B and its liposomal preparations remain most effective treatment choices.     

Identification and Characterization of Leuconostoc carnosum, Associated with Production and Spoilage of Vacuum-Packaged, Sliced, Cooked Ham

Leuconostoc carnosum was shown to be the specific spoilage organism in vacuum-packaged, sliced, cooked ham showing spoilage during 3 weeks of shelf life. Identification of the specific spoilage organism was done by use of phenotypic data and ClaI, EcoRI, and HindIII reference strain ribopatterns. One hundred L. carnosum isolates associated with the production and spoilage of the ham were further characterized by pulsed-field gel electrophoresis (PFGE), together with some meat-associated Leuconostoc species: L. citreum, L. gelidum, L. mesenteroides subsp. dextranicum, and L. mesenteroides subsp. mesenteroides. ApaI and SmaI digests divided the industrial L. carnosum strains into 25 different PFGE types, ApaI and SmaI types being consistent. Only one specific PFGE type was associated with the spoiled packages. This type also was detected in air and raw-meat mass samples. The spoilage strain did not produce bacteriocins. Only seven isolates belonging to three different PFGE types produced bacteriocins. Similarity analysis of the industrial L. carnosum strains revealed a homogeneous cluster which could be divided into eight subclusters consisting of strains having at most three-fragment differences. The L. carnosum cluster was clearly distinguished from the other meat-associated leuconostoc clusters, with the exception of the L. carnosum type strain. Ribotyping can be very helpful in the identification of L. carnosum, but its discriminatory power is too weak for strain characterization. PFGE provides good discrimination for studies dealing with the properties of homogeneous L. carnosum strains.     

Production of very-high-amylose potato starch by inhibition of SBE A and B

High-amylose starch is in great demand by the starch industry for its unique functional properties. However, very few high-amylose crop varieties are commercially available. In this paper we describe the generation of very-high-amylose potato starch by genetic modification. We achieved this by simultaneously inhibiting two isoforms of starch branching enzyme to below 1% of the wild-type activities. Starch granule morphology and composition were noticeably altered. Normal, high-molecular-weight amylopectin was absent, whereas the amylose content was increased to levels comparable to the highest commercially available maize starches. In addition, the phosphorus content of the starch was increased more than fivefold. This unique starch, with its high amylose, low amylopectin, and high phosphorus levels, offers novel properties for food and industrial applications.