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Microoganisms in fruit and vegetables - Microorganisms in fruits and vegetables

Technical information Food refrigeration and freezing Micro-organisms associated with vegetables and fruits

Micro-organisms associated with fruit and vegetables

Vegetables are usually contaminated by a variety of micro-organisms, soil-related. Prior to freezing vegetables prepared cleaning and washing, to remove dirt and debris, and trimmed and/or cut. Many blanched vegetables for the inactivation of the enzyme activity during the frozen storage, and it also affects the microbiological quality, removal of plant cells, such as infectious bacteria. Further processing and cooling of the products can recontaminate vegetables before freezing. However, frozen vegetables, are not considered as high-risk foods and rarely, food-related, because the pathogens are not able to reproduce at freezing temperatures and cooking before consumption.

Although pollution Enterobacteriaceae is commonplace, poor hygienic practices is not the only reason for this, since the members of this family are commonly associated with plants and plant materials. Forms that are often found in vegetables and can be a good indicator of quality. Lactic acid bacteria that are normally present in high numbers in the range between 101 and 105 CFU/g Sometimes, high spore loads can be found on crops that have been sprayed with insecticides containing Bacillus thuringiensis.

This bacterium is closely related to B. cereus subgroups and kills with protein crystals that are toxic to insects. Care should be taken to ensure that insecticides, medicines used for agricultural crops, not containing enterotoxin-producing of spore-forming microorganisms (Yang et al., 2003) and strains used for this purpose, should be screened for this characteristic. Because B. thuringiensis can be easily distinguished from B. cereus and microbiological criteria often include limitations on the number of B. cereus, the use of such sprays can lead to problematic situations, especially if you use sprays contain strains that can produce enterotoxin which is associated with B. cereus diarrhea syndrome.

Most fruits, which are intended to be frozen collect ripe, soas there is no possibility for maturing after they have been processed. In addition, frozen fruit is commonly consumed after thawing, without heating. Micro-organisms associated with fruits include mold, yeast, protozoa, viruses and bacteria. Fruits, vegetables, usually washed (e.g. with chlorinated water) and some particularly sensitive in handling, and easily damaged. Some raised his hand and/or sorted and, thus, susceptible to contamination by pathogenic for humans. There are various drugs that are sold for purification/decontamination of fruits and vegetables, and they have limited success in addressing microbiological contamination and/or impede their growth. Unlike vegetables, blanching vegetables in most cases apply, except for fruits used in products that are further cooking before consumption, such as the bakery. Typical micro-organisms associated with fruit before freezing are the same as those for raw materials harvesting, as well as other introduced through further processing.

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