Eukaryotic microorganism: Molds

Molds are eukaryotic microorganisms in the kingdom of fungi that grow as multicellular filaments called hyphae, collectively called a mycelium. Hyphae are cylindrical, thread-like structures 2-1 μm in diameter and up to several centimeters. Molds are often seen as fuzzy or fluffy masses on bread and other food products, especially acidic products.

The molds often assume vivid colors from the pigments they produce in spores for reproductive purposes. Molds are the second most common microbial contaminants in the clean room, and under certain circumstances they can become a serious threat. Their nutritional requirements are generally simpler than those of bacteria and they can grow in the absence of significant amounts of moisture.

They resemble microscopic roots and like roots can anchor to ground or tissue, penetrate it and branch and grow unnoticed underneath it. People are most familiar with molds because of their association with food spoilage and the deterioration of materials and equipment through mildew and dry rot.

Aspergillus and Penicillium species tend to be saprophytic and often attack commodities, such as cereal grains and nuts while in storage, although some aspergili can invade in the field. Fusarium species may be plant pathogenic as well as saprophytic types.

Eukaryotic microorganism: Molds

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Mycotoxins in food

Many cereal and other crops are susceptible to fungal attack either in the field or during storage.

The contamination of food and animal feeds with mycotoxins is a worldwide problem, while mycotoxins occurs more frequently under tropical conditions as a result of environment conditions in the field coupled with improper harvesting and bad storage.

Many mycotoxins were initially identified after they had caused a variety of subacute health problems in livestock as well as humans, with many target organs and system affected.

The FAO has estimated that up to 25% of the world’s food crops are significantly contaminated with mycotoxins and that the food losses amount to one billion tons per year.

Fungal infection and subsequently mycotoxins formation can occur in the field, during harvesting or during storage period and processing.

To prevent mycotoxins from entering the food production chain, controls should preferably be applied at the raw materials stage.
Mycotoxins in food

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Bacterial contamination of beef meat

The primary contamination of the meat surface of healthy animals is decisively influenced by the abattoir environment and the condition of the animal.

Varying levels of both Gram-positive and Gram-negative bacteria constitute the initial microbial population.

Bacterial presence is limited almost exclusively to the exterior surface of carcasses unless the surface has been penetrated by utensils allowing transport of bacteria to interior muscle tissues.

The hides of cattle are loaded with bacteria. The intestinal tract of cattle is also loaded with bacteria. Bacteria from intestinal tract may come in contact with the carcass surface if the intestinal tract is rupture during evisceration.

Also, feces during slaughter and rumen contents spilled through the esophagus may additional sources of contamination.

The important spoilage bacteria of fresh meat include Pseudomonas, Acinetobacter/Moraxella, Aeromonas, Alteromonas putrefaciens, Lactobacillus and Brochothrix thermosphacta.

The major end products of metabolism of common meat spoilage organisms are sulfides, amines, acetic acid, lactic acid, isovaleric acid, isobutyric acid, esters and nitriles.
Bacterial contamination of beef meat

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