**6. Herbs, condiments and spices as food preservatives**

Safety and high-quality characteristics of food products are some of the attributes growingly demanded by consumers worldwide. Despite technological advances, either by chemical preservatives or mechanical equipment for inactivation or inhibition of microorganisms, there are still problems concerning food spoilage of biological origin. Attention is concentrated on psychrophiles, halophiles and toxigenic foodborne pathogens. Consequently, natural antimicrobial molecules are interesting tools to control microbial food contamination, in addition to their already well-known flavouring properties. The main commercial objective of adding these compounds to foodstuff is extending their shelf-life and increasing, if possible, their nutricional and organoleptic value.

As mentioned earlier, these natural antimicrobials derive from plant products and, historically, are been in use for a long time in areas as China or India. Nowadays the concentrated use of a large number of condiments/spices is mainly performed in hot climate regions. Virtually every group of food raw materials can be added with one or more plants/herbs/spices that work as food preservatives, as shown in Table 2.

Among the species used for food preservation or that have shown to produce inhibition of food contaminants we find: thyme (*Thymus eigii*), ginger (*Zingiber officinalle*), galangal (*Alpinia galanga*), turmeric (*Curcuma longa*) and fingerroot (*Boesenbergia pandurata*). Cinnamon, cloves and cumin also show antimicrobial effects against pathogens, some of which of foodborne origin, like *Staphylococcus aureus*, *Klebsiella pneumoniae*, *Pseudomonas aeruginosa*, *Escherichia coli*, *Enterococcus faecalis*, *Mycobacterium smegmatis*, *Micrococcus luteus* and even *Candida albicans*. We also find condiments as allspice, bay leaf, caraway, coriander, cassia bark and liquorice as a way to eliminate or inhibit foodborne pathogens. In particular, olive tree leaves (*Olea europaea*) shows effects against important species as *Campylobacter jejuni*, *Helicobacter pylori* and *Staphylococcus aureus*.

The molecules interviening in the antimicrobial process have been object of a specific section within this chapter, but among thje most commom we usually find α-pinene, cineole, limonene, linalool and geranyl acetate.

In terms of use for food preservation, these natural antimicrobial agents may pose problems that must be addressed, namely the existence of antagonism between different agents, degradation of organoleptic profile and the existence of toxic effects for the consumer. These issues have to be considered seriously and the solutions may be in continuing research of the health effects and mainly in finding ways to lower the sensorial perception of some spices/herbs (optimization of food formulation) or by guaranteeing food preservation by combining different methods (conventional techniques plus addition of natural antimicrobials).

Researchers must have in mind, as mentioned earlier, that different plants may have the same antimicrobial phytochemicals, although they may be in different concentrations, resulting in different MIC for the same molecule. Moreover, the same plant may have more than an antimicrobial molecule, resulting in effects that can not be easily evaluated. An

Safety and high-quality characteristics of food products are some of the attributes growingly demanded by consumers worldwide. Despite technological advances, either by chemical preservatives or mechanical equipment for inactivation or inhibition of microorganisms, there are still problems concerning food spoilage of biological origin. Attention is concentrated on psychrophiles, halophiles and toxigenic foodborne pathogens. Consequently, natural antimicrobial molecules are interesting tools to control microbial food contamination, in addition to their already well-known flavouring properties. The main commercial objective of adding these compounds to foodstuff is extending their shelf-life

As mentioned earlier, these natural antimicrobials derive from plant products and, historically, are been in use for a long time in areas as China or India. Nowadays the concentrated use of a large number of condiments/spices is mainly performed in hot climate regions. Virtually every group of food raw materials can be added with one or more

Among the species used for food preservation or that have shown to produce inhibition of food contaminants we find: thyme (*Thymus eigii*), ginger (*Zingiber officinalle*), galangal (*Alpinia galanga*), turmeric (*Curcuma longa*) and fingerroot (*Boesenbergia pandurata*). Cinnamon, cloves and cumin also show antimicrobial effects against pathogens, some of which of foodborne origin, like *Staphylococcus aureus*, *Klebsiella pneumoniae*, *Pseudomonas aeruginosa*, *Escherichia coli*, *Enterococcus faecalis*, *Mycobacterium smegmatis*, *Micrococcus luteus* and even *Candida albicans*. We also find condiments as allspice, bay leaf, caraway, coriander, cassia bark and liquorice as a way to eliminate or inhibit foodborne pathogens. In particular, olive tree leaves (*Olea europaea*) shows effects against important species as *Campylobacter* 

The molecules interviening in the antimicrobial process have been object of a specific section within this chapter, but among thje most commom we usually find α-pinene, cineole,

In terms of use for food preservation, these natural antimicrobial agents may pose problems that must be addressed, namely the existence of antagonism between different agents, degradation of organoleptic profile and the existence of toxic effects for the consumer. These issues have to be considered seriously and the solutions may be in continuing research of the health effects and mainly in finding ways to lower the sensorial perception of some spices/herbs (optimization of food formulation) or by guaranteeing food preservation by combining different methods (conventional techniques plus addition of natural

inhibition or decrease in bacterial population may be due to different mechanisms.

**6. Herbs, condiments and spices as food preservatives** 

and increasing, if possible, their nutricional and organoleptic value.

plants/herbs/spices that work as food preservatives, as shown in Table 2.

*jejuni*, *Helicobacter pylori* and *Staphylococcus aureus*.

limonene, linalool and geranyl acetate.

antimicrobials).


Table 2. List of herbs/spices/condiments or natural antimicrobial molecules used in different groups of foodstuff and their potential targets (adapted from Tajkarimi *et al*., 2010).
