Stability of mycotoxins during food processing Bullerman, Lloyd B.; Bianchini, Andreia
International journal of food microbiology,
10/2007, Letnik:
119, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
The mycotoxins that commonly occur in cereal grains and other products are not completely destroyed during food processing operations and can contaminate finished processed foods. The mycotoxins most ...commonly associated with cereal grains are aflatoxins, ochratoxin A, fumonisins, deoxynivalenol and zearalenone. The various food processes that may have effects on mycotoxins include sorting, trimming, cleaning, milling, brewing, cooking, baking, frying, roasting, canning, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize the highest temperatures having greatest effects. In general the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. However, roasting and extrusion processing show promise for lowering mycotoxin concentrations, though very high temperatures are needed to bring about much of a reduction in mycotoxin concentrations. Extrusion processing at temperatures greater than 150 °C are needed to give good reduction of zearalenone, moderate reduction of alfatoxins, variable to low reduction of deoxynivalenol and good reduction of fumonisins. The greatest reductions of fumonisins occur at extrusion temperatures of 160 °C or higher and in the presence of glucose. Extrusion of fumonisin contaminated corn grits with 10% added glucose resulted in 75–85% reduction in Fumonisin B
1 levels. Some fumonisin degredation products are formed during extrusion, including small amounts of hydrolyzed Fumonisin B
1 and
N-(Carboxymethyl) — Fumonisin B
1 and somewhat higher amounts of
N-(1-deoxy-
d-fructos-1-yl) Fumonisin B
1 in extruded grits containing added glucose. Feeding trial toxicity tests in rats with extruded fumonisin contaminated corn grits show some reduction in toxicity of grits extruded with glucose.
Lactic acid bacteria were isolated from four different sourdough bread cultures previously investigated for antifungal activity. A total of 116 isolates were obtained and screened for antifungal ...activity against a battery of molds. The most inhibitory isolate obtained was identified by API 50 CHL and 16s ribosomal RNA genotyping and found to be
Lactobacillus paracasei ssp
. tolerans. This isolate completely inhibited the growth of
Fusarium proliferatum M 5689, M 5991 and
Fusarium graminearum R 4053 compared to controls in a dual agar plate assay.
Sourdough starter cultures are rich sources of endogenous lactic acid bacteria. The extended shelf lives of sourdough breads are attributed to a large array of organic acids and low-molecular-weight ...metabolites produced during the fermentation process. Different species belonging to the lactic acid bacteria group of microorganisms, mainly Lactobacillus and Leuconostoc, are increasingly gaining the attention as possible means for inhibiting mold growth in animal feed and human food chains. In addition, certain lactic acid bacteria strains isolated from sourdough starters were also shown to reduce mycotoxins concentrations in contaminated products either by binding or degradation. This short review will summarize the findings in this context that pertain to lactic acid bacteria isolated specifically from sourdough starters and acquaint the reader with the most recent advancements in this bio-preservation trend.
Lactobacillus paracasei subsp. tolerans, isolated from a traditional sourdough bread culture and previously shown to have antifungal activity against Fusarium species, was tested for inhibition of ...growth of Fusarium proliferatum M 5991 and M 5689 and F. graminearum R 4053 in a liquid medium setting. This isolate completely inhibited the growth of F. proliferatum M 5689 and M 5991 and F. graminearum R 4053, whereas such growth was not inhibited in the control in a supernatant agar plate assay. When this isolate was tested using 2M medium (MRS-modified Myro media) known for supporting Fusarium growth and trichothecene production, it was found to inhibit fungal growth but promote mycotoxin production at the same time. The antifungal activity was determined to be the result of organic acids and low pH. The mechanism of the mycotoxin production promotion requires further investigation.
Aspergillus flavus and the closely related subspecies parasiticus have long been recognized as major contaminants of organic and nonorganic items. A. flavus, a common soil fungus, can infest a wide ...range of agricultural products. Some A. flavus varieties produce aflatoxins, which are carcinogenic toxins that induce liver cancer in laboratory animals. A. flavus var. flavus, A. flavus subsp. parasiticus, and A. nomius share the ability to produce aflatoxins. Identification of the A. flavus species group is mainly based on the color and macroscopic and microscopic characteristics of the fungus. A. flavus growth and aflatoxin biosynthesis depend on substrate, moisture, temperature, pH, aeration, and competing microflora. The growth of A. flavus and aflatoxin production are sometimes unavoidable. Aflatoxins are considered natural contaminants; the ideal control approach is prevention of mold growth and aflatoxin production. The detection of members of the A. flavus species group in foods and feed is generally carried out by using plate techniques such as surface spread or direct plating. Research on alternative fungal detection methods is still in its infancy. Few immunoassay techniques have been investigated in this regard. Aflatoxins are generally analyzed by chemical methods, although immunochemical methods which use antibodies are becoming common analytical tools for aflatoxins
The objective of this study was to determine loss of toxicity of zearalenone in extruded cereal-based products by the MTT (tetrazolium salt) cell proliferation assay using a sensitive MCF-7 human ...breast cancer cell line and to compare the results to chemical (high-performance liquid chromatography, HPLC) and biochemical (enzyme-linked immunosorbent assay, ELISA) methods of analysis. A split−split plot design was used for the extrusion process experiments at temperatures of 150, 175, and 200 °C and screw speeds of 70 and 140 rpm. The initial zearalenone concentration in the artificially contaminated corn grits with Fusarium graminearum was found at a mean concentration of 37.88 μg/g as measured by HPLC. The percent reductions of zearalenone in the contaminated corn grits upon extrusion processing were in the ranges of 67−81, 60−72, and 66−78% as measured by HPLC, ELISA, and the MTT cell proliferation assay, respectively. The MTT cell proliferation assay results were more closely correlated with HPLC results (r = 0.96) than ELISA results (r = 0.83). The MTT cell proliferation assay was demonstrated to be a useful method for quantification of zearalenone as well as a potential toxicity screening method for contaminated extruded cereal-based products. Keywords: Zearalenone; extrusion processing; detoxification; MTT bioassay; MCF-7 cell line
The objective of this study was to determine the loss of toxicity of deoxynivalenol in extruded cereal-based products by the tetrazolium salt (MTT) bioassay using a sensitive Chinese hamster ovary ...(CHO-K1) cell line and to compare the results to chemical (high-performance liquid chromatography, HPLC) and biochemical (enzyme-linked immunosorbant assay, ELISA) methods of analysis. A split−split plot design was used for the extrusion process experiments at temperatures of 150, 175, and 200 °C and screw speeds of 70 and 140 rpm. The initial mean deoxynivalenol concentration in the corn grits artificially contaminated with Fusarium graminearum was found to be 23.5 μg/g as measured by HPLC. The percent reductions of deoxynivalenol in the contaminated corn grits upon extrusion processing ranged from 22 to 35%, from 21 to 34%, and from 21 to 37% as measured by HPLC, ELISA, and MTT bioassay, respectively. The MTT bioassay results were more closely correlated with HPLC (r = 0.90) results than with ELISA results (r = 0.78). The MTT bioassay, using a sensitive mammalian cell line, was demonstrated to be a useful method for quantification of deoxynivalenol as well as a potential toxicity screening method for contaminated extruded cereal-based products. Keywords: Deoxynivalenol; extrusion processing; detoxification; MTT bioassay; Chinese hamster ovary cell line; cytotoxicity
This study was designed to determine the efficacy of extrusion in reducing fumonisin B1 in corn flaking grits in the presence and absence of glucose. In addition, degradation products of fumonisin B1 ...during extrusion were identified and quantitated with a mass balance approach. Uncontaminated clean corn grits, grits spiked with 30 µg/g fumonisin B1, and grits fermented with Fusarium verticillioides M-2552 (40–50 µg/g fumonisin B1) were extruded in the presence and absence of glucose (10%, w/w) using a single-screw extruder. Extrusion decreased fumonisin B1 by 21–37%, whereas the same process with added glucose further decreased fumonisin B1 by 77–87%. LC−fluorescence and LC-MS showed that most fumonisin in the extruded samples without added glucose was the fumonisin B1 form, whereas the main degradation product in grits extruded with glucose was N-(deoxy-d-fructos-1-yl)fumonisin B1. The formation of hydrolyzed fumonisin B1 was not significant during extrusion. Results suggest that extrusion in the presence of glucose may reduce fumonisin B1 in corn grits significantly.
The antimicrobial activities of four long-chain food-grade polyphosphates were studied at concentrations allowed in the food industry (<5,000 ppm) in defined basal media by determining the inhibition ...of growth of three gram-negative and four gram-positive spoilage and pathogenic bacteria. Both generation time and lag phase of Escherichia coli K-12, E. coli O157:H7, and Salmonella Typhimurium were increased with all of the polyphosphates tested. Bacillus subtilis and Staphylococcus aureus were more sensitive to polyphosphates, but not in all cases, with multiphased growth. The growth of Lactobacillus plantarum was inhibited by polyphosphates at concentrations above 750 ppm, but the lag time of Listeria monocytogenes was shortened by the presence of polyphosphates. No single polyphosphate was maximally inhibitory against all bacteria. Polyphosphates with chain lengths of 12 to 15 were significantly different from those with chain lengths of 18 to 21 depending on the organism and concentrations of polyphosphate used. Overall, higher polyphosphate concentrations resulted in greater inhibition of bacterial growth.
Scope: Fumonisin B1 (FB1) is a mycotoxin found in maize and maize-based foods. It causes animal diseases and is a suspected risk factor for cancer and birth defects in humans. Extrusion cooking ...reduces FB1 concentrations in maize however toxicity caused by unknown degradation or FB1-matrix reaction products might persist. Methods and results: To test the efficacy of extrusion to reduce FB1 toxicity, Fusarium verticillioides fermented corn (= maize) grits (Batch-1= 9.7 ppm FB1; Batch-2= 50 ppm FB1) were extruded without (Batch-1E; Batch-2E) or with 10% glucose supplementation (Batch-1EG; Batch-2EG). FB1 concentrations were reduced 64% (Batch-2E) to 94% (Batch-1EG) after cooking. When the uncooked and processed grits were fed (50% w/w in rodent chow) to rats for up to 8 weeks, FB1 intakes averaged 354, 103, and 25.1 çg/kg body weight/day for Batch-1, Batch-1E and Batch-1EG and 1804, 698, and 222 çg/kg body weight/day for the Batch-2, Batch-2E and Batch-2EG, respectively. Nephrotoxicity including apoptotic lesions and elevated sphingoid base concentrations decreased in a dose-dependent manner in groups fed Batch-1, Batch-1E, Batch-2, Batch-2E, or Batch-2EG and was absent in the Batch-1EG group. Conclusion: Extrusion cooking, especially with glucose supplementation, is potentially useful to reduce FB1 concentrations and toxicity of FB1-contaminated maize.
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