In baking industry, bread occupies a unique position both in production and utilization as compared to other bakery products. The ingredients of bread are supportive to growth of microorganisms and multiplication at different stages of bread production, slicing and wrapping. The main types of microbial spoilage of bread are moldiness and ropiness which are troublesome for bakers. Ropiness won’t be studied due to the fact that it is caused by bacterial organism which unfortunately is not a fungal organism and as a result, not in the scope of study for this research work. Mold growth often begins within a loaf of sliced bread, where more moisture is available than at the surface, especially in the crease (Liaqat, 1988). 

Food safety is a known problem worldwide, affecting hundreds of millions of people that suffer from contaminated food. World Health Organization (WHO) defines this issue as “one of the most widespread health problems and a major cause of the reduction in economic productivity (WHO, 2007).

Nowadays, consumers are continuously concerned with the growing number of illness caused by some pathogenic and spoilage microorganisms in food and also for the safety of foods containing synthetic preservatives. Thus, it shows a growing interest about the replacement of synthetic preservatives with natural, effective and nontoxic antimicrobial compounds. There is growing interest in using natural antimicrobial compounds, such as extracts and essential oils (EOs) of species and herbs, for food conservation. The effect of plant extracts on microorganisms have been studied by a large number of researchers in different parts of the world (Kumar et al., 2006; Mathabe et al., 2006) and the use of a variety of plant extracts and phytochemicals, both with known antimicrobial properties, can be of great significance in therapeutic treatments. Many plants have been used because of their antimicrobial properties, which are due to compounds synthesized in the secondary metabolism of the plant. These products are known by their active substances, such as, the phenolic compounds which are part of the essential oils, as well as in tannin (Nascimento et al., 2000).

Since, bread is an important part of our daily diet; therefore, ways and means should be explored to increase its shelf life. The shelf life of bread can be increased by improving the hygienic conditions of mixing and baking premises and ensuring sterilized environment. To enhance the shelf life of bread, several chemical antimicrobial agents have been employed but they are considered responsible for many carcinogenic and teratogenic attributes and residual toxicity. Due to these reasons, consumers tend to be doubtful of chemical additives and thus the demand for natural preservatives has been intensified (Skandamis et al., 2001).

 Essential oils are volatile oily liquids obtained from different plant parts and widely used as food flavors (Burt, 2004). They are variable mixtures of essential terpenoids, especially monoterpenes (C10) and sesquiterpenes (C15), although diterpenes (C20) may also be present, and of a variety a low molecular weight aliphatic hydrocarbons, acids, alcohol, aldehydes, phenolic compounds, acyclic esters, or lactones (Rota et al., 2004). The composition, structure, as well as functional groups of the oils play an important role in determining their antimicrobial activity. It has been demonstrated that the essential oils exercises their antimicrobial activity by causing structural and functional damages to the microbial cell membrane. It is also indicated that the optimum range of hydrophobicity is involved in the toxicity of the essential oils (Goni et al., 2009).

Essential oils from spices and herbs are the most promising natural antimicrobials, because they do not cause microbial resistance due to the diversity of mechanisms of action. They have a Generally Recognized Asafe (GRAs) status given by the United States Food and Drug Administration (Food and Drug Administration, USA, 2011), meaning that they are generally recognized and safe for human consumption without limitations on intake and commonly accepted by consumers.