In the industrial practice Howard mould count (Howard, 1911) is used for the estimation of mould contamination of foods. It was developed originally for the investigation of mould contamination of tomato purée. It is also used nowadays for quality control purposes for other food products as well. Recently this constitutes the basis of the acceptance of the finished products in international trade. This technique demands experts with a lot of practice and morphological proficiency. The investigation makes use of eyes and so the tiredness of the investigator can cause uncertainties.The possibility of other methods for the determination of mould contamination of tomato purée was investigated to replace the Howard method. The NIR technique — as a rapid, non-destructive, reagentless and accurate method — was anticipated as a suitable method for the mentioned purpose. Canned tomato purée had been allowed to become mouldy then the sample was blended with non-mouldy samples in different ratio, so a series of tomato purées containing known amounts of mouldy purée was prepared. Howard mould counts and ergosterol content — another mould contamination relating value — was used as reference for NIR calibration.At quantitative investigation better results were obtained using ergosterol values. The best correlation coefficient (R=0.93) and the smallest standard error of calibration (SEC=0.008 mg g−1 ergosterol) was achieved with triangular smoothing and second derivation of the spectra. At qualitative investigation Polar Qualification System (PQS) was used. Clusters between samples with low and high ergosterol levels could be separated.
Authors:D. Hadanich, J. Perédi, M. Juhász-Román, and B. Nagy
In the microflora of sunflower seeds stored in domestic stores the,
species dominate, while those of
Penicillium, Trichoderma, Stemphylium
spp. are present in lower numbers. During model tests (cca 20% seed moisture content, 25 °C, 4 weeks storage) the
species were almost completely eliminated and on the seeds mainly
species, characteristic of stores, propagated. The moulds significantly deteriorated the quality of the seed and that of the produced oil and meal (reproductive ability, germinating power, oil content, lipoxygenase enzyme activity, acid value, peroxide value, fatty acid composition, UV absorbance, colour, sensorial properties, as well as the protein content, amino acid composition, colour and the smell of the meal), but no aflatoxin production occurred. The findings offer a comprehensive picture on the multiple destructive effects of incorrect storage.
Authors:K. Tóth, K. Balogh, A. Bócsai, and M. Mézes
Forage plants may become contaminated by mycotoxins already on the cropland as a result of mould infection, the degree of which can be diminished by the use of appropriate agrotechnical methods or resistant plant cultivars. During storage, the main goal is to prevent further mould infection and mycotoxin contamination. In that period, the moisture content of feedstuffs and the mould contamination of storage spaces, which can be minimised by the use of fungicidal products, are the most critical factors. Feed manufacturing processes do not substantially decrease the mycotoxin content of feedstuffs, and the efficiency of the recommended chemical and/or heat treatment procedures is also questionable as they are expensive and may reduce the nutrient content. To minimise the adverse effects of mycotoxins on animals, the use of products capable of binding and biologically transforming mycotoxins is also recommended; however, such products have varying efficacy.
Changes in the consumption habits of the population forces food industry to produce traditional products in modern ways, sometimes not taking into account the modified safety issues. The aim of this study has been to compare hazards and critical control points for traditional and industrial cremeschnitte production. The result shows that the traditional cremeschnitte production includes two additional critical control points, cooking and moulding of egg cream basis, which is essential for safety. In addition, the results of microbial analysis pointed out that the traditional cremeschnitte is safer than the industrial one produced from dried cream powder when comparing Escherichia coli, total aerobic count, and mould contamination (P<0.05). Moreover, our controlled contamination test with E. coli of raw material shows that the traditional cremeschnitte production process reduces microbiological hazard even in the worst-case scenario. All this indicates that traditional food safety practices are not granted and should not be neglected in new production technologies.
There is a clear need for application of proper methods for measuring food quality and safety in the globalized food-webs. Numerous instrumental methods have been established in the course of the 20th century and are developing further, together with data analysis techniques, for such purposes. Among them, near-infrared and fluorescence spectroscopic methods and chemical sensor arrays called electronic noses show particular promise for rapid, non-destructive, non-invasive and cost-effective ways for assessing changes and enhancing control during processing and storage of foods. Their key advantages as analytical tools are 1) their relatively high speed of analysis, 2) the lack of a need to carry out complex sample preparation or processing, 3) their relatively low cost, and 4) their suitability for on-line monitoring or quality control. The present survey attempts to demonstrate examples from the above areas, limiting itself mainly to monitoring some quality indices which contribute to the functionality or acceptability of foods as affected by alternative processing technologies, or loss of freshness/microbial safety, or developing spoilage during storage and marketing. These instrumental methods are correlative techniques: they must be calibrated first against (traditional) reference properties, and the instrumental data are evaluated with the help of chemometric methods. Near-infrared (NIR) spectroscopy can be used in either the reflectance or the transmittance mode. NIR spectra transformed to mathematical derivatives allows subtle spectrum changes to be resolved. Selected examples from the extensive NIRS literature relate to assessment of the quality of frozen fish, predicting cooking loss of chicken patties, detecting complex physico-chemical changes of minced meat as a function of the intensity of high hydrostatic pressure treatment, comparing changes of NIR spectrometric “fingerprints” caused by gamma radiation or high pressure pasteurization of liquid egg white. Changes of NIR spectra reflect several parameters which suit the evaluation of loss of freshness, and onset of spoilage of various foods. NIR spectroscopy shows an application potential for rapid detection of bacterial or mould contamination. It may serve as a tool for detecting initial stages of mobilization processes during germination of cereal grains, or even for GMO screening. Spectrofluorometic measurements have shown potential, e.g. to monitor lipid oxidation and development of meat rancidity, to differentiate between raw and processed milks, and to monitor fish and egg freshness. Electronic noses containing chemical sensor arrays offer a rapid method for evaluation of head-space volatiles of food samples, important for characterizing quality and safety. Such gas sensors may be able to classify storage time, and determine spoilage, either earlier or at the same time as the human senses, or “sniffing out” bacterial pathogens or (toxigenic) fungal growth on certain foods. Electronic nose sensing is also a promising method for detecting quality changes of fruit- and vegetable products non-destructively. In relation to some examples to be presented in the paper, certain software developments as qualitative classification tools made by Hungarian scientists will be pointed out.
, F. & Kiss, I.
(1986a): Penészfertõzöttség kimutatása kémiai módszerrel. (Determination of mouldcontamination using chemical method.) -in:
Magyar Mikrobiológiai Társaság Nagygyűlése
, Gödöllő, Sept. 1–3. Abstract p. 8
Authors:B. Salamon, F. Zakariás, B. Csehi, G. Kiskó, and I. Dalmadi
they are very sensitive to mechanical damage and mouldcontamination. During transport, processing, and storage they easily lose their sensory qualities (colour, texture, and flavour) ( Gao et al., 2016 ). HHP processing is a good alternative to