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Risks for gastric cancer in relation to diet and other environmental factors are receiving renewed attention. New developments include the emerging relationship between Helicobacter pylori infection and an increased risk for gastric cancer, and positive results of chemoprevention trials in decreasing gastric cancer risk with the use of beta-carotene and vitamin E supplements. Factors that may enhance risk include consumption of nitrites, nitrates, alcohol, and highly salted, pickled, fermented, or smoked foods. Other environmental factors which may promote cancer are H. pylori infection, inappropriate food storage, metal and cement dust exposure, and cigarette smoking. High intakes of fruits and vegetables or of antioxidants, such as beta-carotene, vitamin E, and vitamin C may decrease risk.
The quantitative analysis of benzoic and sorbic acid, methyl, ethyl and propyl esters of p-hydroxybenzoic acid and saccharin in foodstuffs is described. These compounds are quantitatively extracted with disposable clean-up columns packed with Extrelut and simultaneously determined by high-performance liquid chromatography on reversed-phase columns. Complicated matrices such as cheese, cake, ketchup and chocolate were tested and recoveries were generally better than 95% in the concentration ranges normally used in the food industry.
In a structure analysis of the compounds of the genus Piper (Family Piperaceae), we identified five phenolic amides from Piper nigrum, seven compounds from P. retrofractum, and two compounds from P. baccatum. All the phenolic amides possess significant antioxidant activities that are more effective than the naturally occurring antioxidant, alpha-tocopherol. One amide, feruperine, has antioxidant activity as high as the synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Naturally occurring antioxidants, therefore, may surpass BHA and BHT in their ability to inactivate mutagens in food.
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The human environmental hazard in the last ten years is the most important problem for public health and prevention. Particularly, in agriculture, the continuous use of increased quantities of pesticides and nitroso compounds, such as fertilizers, is involved. The evaluation of exposure risk is complex because of A: --a1) the numerous categories of chemical substances used as pesticides. --a2) the different catabolic pathways that are followed by organisms for detoxification. B: the different categories of exposed people such as: --b1) industrial workers who are exposed to a single compound, in time; --b2) agricultural workers whose exposure is multiple, prolonged over time, and often, even at high doses; --b3) general population whose exposure is from residues from the food chain. C: different kinds of exposure: --c1) accidental, acute and massive, the most studied; --c2) chronic exposure, the most difficult to quantity and of which we do not have any chemical features available, nor do we have parameters or sensitive or specific exposure indexes. The complexity of exposure and the difficulty to derive adequate indexes both in rural environments and in the general population, explains why there are no existing regulation parameters regarding exposure of agricultural workers where as they exist for industrial workers (MAC and TLV). When it is not possible to evaluate the quantity of substances that are used and absorbed during the work shift, it is necessary to revert to effect index measurements. On one hand these refer to the chemical nature of the substances employed and to the knowledge regarding the catabolism that, from the compound, brings about metabolic inactivation, and on the other hand refers to metabolic modification which is easily measured with blood tests and urinalysis. For example urinary metabolites of substances assumed through various ways (DichloroDiphenyl Acetic Acid-DDA-) and DDT or modifications of enzymes activity e.g. cholinesterasis following the manipulation of phosphoric compounds or alkaline phosphatasis from dithiocarbamates. Our experimental testing found that the systematic reduction of enzymes activity in serum of workers exposed to dithiocarbamates cannot be explained exclusively considering the chelating action of dithiocarbammates. In fact the chelating of zinc, a metal which is present in the prosthetic group of alkaline phosphatasis, can be carried out placing the serum enzymes in the presence of growing concentrations of dithiocarbamates. The concentration of dithiocarbamates that is able to determine the complete inactivation of the enzymes is high, equal to 8 mg/ml.(ABSTRACT TRUNCATED AT 400 WORDS)
The combined and independent effects of sucrose, sodium chloride, potassium sorbate, and sodium benzoate on heat inactivation of conidia of Aspergillus flavus and Penicillium puberulum, ascospores of Byssochlamys nivea, and vegetative cells of Geotrichum candidum were studied. In addition, the effects of solutes and preservatives on colony formation by unheated and heated conidia of A. flavus were evaluated. Increased concentrations of sucrose were accompanied by increased tolerance to heat by A. flavus, B. nivea, and G. candidum. Low concentrations (3 and 6%) of sodium chloride protected A. flavus and G. candidum, whereas up to 12% sodium chloride protected B. nivea, but had little effect on the heat stability of P. puberulum. Potassium sorbate and sodium benzoate acted synergistically with heat to inactivate all four molds. At the same concentration, the two preservatives had varied degrees of effectiveness on molds and were influenced by the type of solute in the heating menstrua. Heated conidia of A. flavus had increased sensitivity to preservatives and reduced water activity, whether achieved by the presence of sucrose or sodium chloride, thus demonstrating heat-induced injury. At the same concentration, potassium sorbate was clearly more inhibitory than was sodium benzoate to colony formation by A. flavus, and the presence of sucrose and sodium chloride enhanced this inhibition.
Two patients with chronic idiopathic urticaria in whom remissions were achieved with dye- and preservative-elimination diet had exacerbations of their urticaria when they were challenged under double-blind, placebo-controlled conditions with butylated hydroxyanisole and butylated hydroxytoluene. After elimination of butylated hydroxyanisole and butylated hydroxytoluene from their diets, there was marked abatement of the frequency, severity, and duration of their urticaria. These antioxidants appear capable of aggravating symptoms in certain patients with chronic urticaria.
Sodium sulphite and sodium benzoate induce in Vicia faba root meristems: (1) dose-dependent reduction in mitotic figures, (2) intact and severed anaphase bridges, (3) premature chromosome condensation heading to pycnotic nuclei, and (4) chromatin erosion in interphase nuclei. The effects are due to the anions and not due to the sodium ions. Complete recovery of mitotic figures and normal chromosome configurations were observed within the first 23-46 h of regrowth. Recovery was accompanied by severed anaphase bridges and micronuclei of various shapes. Both benzoate and sulphite inhibit DNA synthesis in Vicia faba root meristems. Sulphite was more effective than benzoate.
The occurrence of aflatoxins in market betel nut samples was studied. It was observed that several betel nut samples were infested with aflatoxin-producing fungus, Aspergillus flavus. Out of 32 samples collected from various places, 12 were positive for aflatoxin. Aflatoxin B1 was detected in all the positive samples. Other aflatoxins were also detected in some samples. Boric acid, propionic acid and potassium metabisulphite were used for the control of aflatoxin B1 on betel nuts. Propionic acid was most effective in inhibiting aflatoxin production on betel nut after intervals of 2 (62%) and 4 (85%) weeks. Controlling the occurrence of aflatoxin could safeguard the users from the health hazards of aflatoxins.
Mutants of Salmonella Enteritidis selected following exposure to the sanitizer chlorine or to the preservatives sodium nitrite, sodium benzoate or acetic acid show resistance to multiple antibiotics (tetracycline, chloramphenicol, nalidixic acid, and ciprofloxacin). Complementation experiments with a functional marR restored antibiotic susceptibility of selected mutants to levels similar to wild-type strains, suggesting that mar mutation was responsible for resistance. The multiple antibiotic resistance (mar) operon is a global regulator controlling intrinsic resistance towards structurally and functionally unrelated antibiotics and other noxious agents. Mutants selected after exposure to an inducing agent maintained elevated antibiotic resistance after serial subculture in media void of the inducing agent. Results highlight the importance of monitoring the use of antimicrobial agents to ensure that concentrations capable of inactivating target pathogens are used.
Analytical methods suitable for the detection of irradiated foods are reviewed. The detection methods are classified as physical, chemical, microbiological and biological, respectively. Reliability, robustness, sensitivity, accuracy and simplicity of each method are discussed.
Thermo-optical absorbance (TOA) detection using a KrF excimer waveguide laser for detection of benzoic acid, dehydroacetic acid and sorbic acid separated by capillary electrophoresis (CE) was studied. Detection limits were, on average, ten times better than those for on-column UV absorbance methods with CE, and two or more times better than those for UV absorbance with HPLC. The influence of increased laser power on TOA detection sensitivity was found to be strong for benzoic and dehydroacetic acids but quite weak for sorbic acid. It was discovered that photoisomerization of sorbic acid (2,4-hexadienoic acid) occurred readily in the detection volume at moderate laser powers (P(ave) = 3 mW) and increased with slow electroosmotic flows (< 6 cm/min). The TOA method described here shows improved detection sensitivity for CE analyses of compounds having only weak absorptivities (< 5% of maximum) at lambda = 248 nm, and thus demonstrates its utility for determination of a variety of analytes in a single separation.
Staphylococcus aureus was grown in a rich peptone medium which became alkaline with continued incubation. Cells were grown at 37 degrees C and in the same medium containing 1 M NaCl at 46 degrees C, a temperature at which this organism can grow only when protected by NaCl. Cells of these cultures are hereafter called 37 degrees C-cells and 46 degrees C-cells, respectively. The 37 degrees C-cells harvested when the pH was 7.1 to 7.7 had decimal reduction times (D60-value) of 1.8 to 3.1 min in 50 mM pH 7.2 Tris buffer. The D60 value of 46 degrees C-cells tested in the same way, harvested from cultures at pH 6.6 to 7.6, ranged from 5.3 to a maximum of 12.8 min. In milk, green beans, peas, or beef slurry, the D60-value of 46 degrees C-cells was about four times higher than that of 37 degrees C-cells. Length of survival after freeze-drying in skim-milk powder exposed to air was longest for the cells with the highest D-value. In freeze-dried peas and media acidified with acetic and lactic acids, 46 degrees C-cells survived longer than 37 degrees C-cells. However, the sensitivity of the two kinds of cells to potassium sorbate, sodium benzoate, and sodium propionate was essentially the same, but the 46 degrees C-cells were more resistant to butylated hydroxyanisole and sodium nitrite.
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The extensive literature on natural antimicrobial systems in animals, plants, and microorganisms is surveyed and particular systems are discussed, viz., the peroxidase systems in saliva and milk, singlet oxygen in the phagosome, cecropins and attacins in insects, complement, lysozyme and, to a limited extent, phytoalexins. The review draws attention to the cardinal role of targets on the cell envelopes of alien cells, especially bacteria, and emphasizes a possible approach to preservation based on the selection of specific agents for particular targets. The available evidence suggests that the perturbation of the homeostasis of all the organisms in the mixed flora of a food is unlikely to be achieved by one antimicrobial substance in isolation. Future studies need to consider therefore a tandem approach with two or more agents chosen because of their complementary action. Alternatively, natural system(s) and an established preservative method, either chemical or physical, warrant investigation. The extensive literature on the mechanisms whereby specialist pathogens overcome the defenses of plants and animals emphasizes the inherent dangers of selection leading to the persistent contamination of food processing areas with organisms tolerant of a particular antimicrobial system.
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