Beneficial Role of Microorganisms in Food Industry

微生物play an important role in food industry. As already discussed in the earlier articleContributions of Microbiology in Food Industry它们用于生产各种食品，也负责食物腐败，从而导致中毒和疾病。

Microbial contamination of food products takes places usually on the way from the field to the processing plant, or during processing, storage, transport and distribution or before consumption.

微生物生长和食物腐败

Different food products provide different growth conditions for microorganisms. Microbial growth is controlled by intrinsic factors like nutrients, pH, moisture content, the physical structure of the food and/or extrinsic factors like temperature, relative humidity, gases (CO2, O2).

因此，微生物在外部和内部因素提供的最佳条件下生长，并导致食品的腐败和降解导致酸，臭味或真菌可覆盖的质量。

食物中的微生物生长也会引起颜色变化的可见变化，粉末状生长的沉积，食物表面上的效力等。食物的微生物污染可能发生在食品生产过程中的任何一点：生长，收获，运输，储存，或最终准备。

Spoilage also can occur if foods are not stored properly. Meat and dairy products are rich in protein and fat serves as an ideal environment for microbial spoilage resulting in proteolysis and putrefaction of the food products. Vegetables and fruits have a much lower protein and fat content and undergo a different kind of spoilage.

食品工业中微生物的用途

Currently, more than 3500 traditionally fermented foods exist in the world. They are of animal or vegetable origin and are part of our daily life. Alcoholic drinks are not the only fermented drinks; cocoa beans, coffee grains and tea leaves are fermented after harvest in order to develop their typical flavour profiles.

Bacteria

细菌是最大的单细胞微生物组。医学上重要的细菌的形状分类为Cocci或球形细胞;杆菌或圆柱形或杆状细胞;和螺旋或弯曲的形式。导致细菌的病原或疾病通常是克否化，然而，已知三个革兰氏阳性棒导致食物中毒：Clostridium botulinum,C. perfringens,and Bacillus cereus

Some of the other most common bacteria causing food spoilage, infections and disease areAcinetobacter, Aeromonas, Escherichia, Proteus, Alcaligenes, Flavobacterium, Pseudomonas, Arcobacter, Salmonella, Lactococcus, Serratia, Campylobacter, Shigella, Citrobacter, Listeria, Staphylococcus, Micrococcus, Corynebacterium, Vibrio Enterobacter, Paenibacillus, Weissella, Enterococcus, Yersinia

Different strains of bacteria are also used in production of various food and dairy products. Strains of Streptococcus,Lactobacillus Bifidobacterium那Erwiniaetc. are used in the production of fermented food and dairy products.Streptococcus thermophilus一种ndLactobacillusbulgaricus.一种re used to produce yogurt.

Agriculture Food and Analytical Bacteriology

分析微生物学是一种研究，应用和使用微生物作为用于定量测定某些化合物的试剂。这些程序基于特定微生物对其环境的反应。

如果微生物与对某种化学实体的可测量反应反应并产生合适的结果，则可以根据食品培养，发酵或保存的要求，设计了用于定量估计物质的分析方法。

Molds:

Molds are multicellular filamentous fungi whose growth on foods is usually readily recognized by their fuzzy or cottony appearance. They are mainly responsible for food spoilage at room temperature 25- 30oC and low pH, and have minimum moisture requirement.

模具th时可迅速在谷物和玉米生长ese products are stored under moist conditions. Molds require free oxygen for growth and hence grow on the surface of contaminated food.

Molds also find their use in manufacturing of different foods and food products. They are used in ripening of various types of food products as cheese (e.g. Roquefort,Camembert).

模具也被生长为饲料和食物，用来生产成分，例如用于制作软饮料中使用的面包或柠檬酸的淀粉酶等酶。

Molds are major contributors in the ripening of many oriental foods. A species of嗜睡，用于摇动葡萄生产葡萄酒。使用模具的乳酸发酵导致独特的芬兰发酵牛奶，称为Viili。

Yeasts:

Yeasts have the ability to ferment sugars to ethanol and carbon-dioxide and hence they are extensively in food industry. The most commonly used yeast, the baker’s yeast is grown industrially.

Saccharomyces carlsbergensis最常用于大多数啤酒的发酵。其他重要的酵母菌株是Brettanomyces, Schizosaccharomyce,, Candida, Cryptococcus, Debaryomyces, Zygosaccharomyces, Hanseniaspora, Saccharomyces

Factors Affecting Growth of Microorganisms

To understand theuses of microorganisms in the food industry，必须了解如何使用微生物，因为它们在各种条件和环境中倾向于不同地反应。

• 通过修剪，洗涤，加热，酸洗去除或摧毁它们。
• Adding chemicals like acid or alcohol or by encouraging competition to form organisms.
• 最大限度地减少来自生食或未加工的食品，人员，设备和环境的污染。
• 通过清洁和消毒设备（容器等）来最小化微生物生长。
• 调整储存pH，光穿透，温度和其他环境因子。

虽然影响增长的这些因素中的每一个都可以分开发生，但它可能本质上同时发生。当一个以上的病症有些不适用于微生物生长时，它们的抑制作用是累积的。

要点要记住

• Bacteria, molds and yeast are the most important microorganisms that cause food spoilage and also find the maximum exploitation in production of food and food products.
• 不同的细菌和真菌菌株用于发酵乳制品，用于生产各种培养的奶制品。细菌和真菌都用于这些奶酪生产过程。
• Lactic acid bacteria are used for coagulation of milk that can be processed to yield a wide variety of cheeses, including soft unripened, soft ripened, semisoft, hard, and very hard types.
• 微生物such asLactobacillus and Bifidobacterium一种re used as in food and health industry.
• Spirulina,一种cyanobacterium,一种lso is a popular food source sold in specialty stores.
• 模具用于腐烂的葡萄繁殖n of different varieties of wines.
• Mushrooms（agaricusbisporus）一种re one of the most important fungi used as a food source.
• Alcoholic beverages as beer are produced by fermentation of cereals and grains using different strains of yeasts.