Food contamination and deterioration are still of concern for both consumer and the food industry, although different preservation methods are used; consumers demand healthy food free from synthetic preservatives (Chastain et al. 1982, Chen et al. 1984). Therefore, the search for effective, nontoxic, and natural sources of antimicrobial and antioxidant compounds such as spices and herbs have notably increased in recent years(Loliger 1991, Ceylan et al. 2004, Ak and Gülçin 2008).
Spices and herbs have been added to foods since ancient times not only as flavouring agents but also as preservatives through their antioxidant and antibacterial activity (Beuchat and Golden 1989, Fernández-López et al. 2003).
The international standard organization has defined the spices as vegetable products or mixtures thereof, used for flavouring and seasoning in food (International Organization for Standardization 1995). In Turkish food, spice is defined as a normal compound or mixture of natural compound that is extracted from the seeds, fruit, flower, or trunks of several plants and added to food in order to provide colour, taste, smell, or flavour (Agaoglu et al. 2007).
Previous studies demonstrated that the inhibitory effects of spices and herbs are mostly due to the volatile oils present in their composition, which have strong influences against several types of pathogens, such as compounds present in oregano, clove, cinnamon, garlic, mint, rosemary and cardamom (Angioni et al. 2004, Arqués et al. 2008). However, less antibacterial efficacy was obtained from black pepper, red pepper, chilli powder, cumin and curry powder (Holley and Patel 2005).
range of 0.05–0.1% in food systems. Nevertheless, some spices require higher concentrations. Shan et al. (2007b) demonstrated that many types of spice extracts contained high level of phenolic compounds that possessed strong antibacterial activity against some food-borne pathogen.
In meat products, previous studies have been shown that spice and herbs extracts can significantly reduce number of pathogenic and spoilage bacteria (Fernández-López et al. 2005, Karabagias et al. 2011). However, another study has reported low antimicrobial effects against pathogens in contaminated meat products (Tajkarimi et al. 2010). The effectiveness of spice extracts in meat products can be influenced by different factors such as: type and composition of the spice, amount used, type of microorganisms, composition of the food, pH value, temperature of the environment, protein, lipids, salts, and phenolic substances present in the food (International Commission on Microbiological Specifications for Foods 2005). Moreover, Burt (2004) and Lis-Balchin et al.
(2003) indicated that high fat content in food has a negative effect on the application of plant essential oils (EOs). Eugenol and coriander, clove, oregano and thyme oils displayed high effects against L. monocytogenes, Aeromonas hydrophila and spoilage bacteria in meat products, whereas mustard, cilantro, mint and sage oils were less effective or ineffective (Burt 2004) .
A study carried out by Yin and Chao (2008) demonstrated that roselle extract (Hibiscus sabdariffa L.) considerably inhibited the growth of both susceptible and antibiotic-resistant Campylobacter spp. in contaminated ground beef.
Clove and tea-tree oils controlled Escherichia coli O157:H7 on blanched
high pressure, irradiation, or packaging under a modified atmosphere can be used to control the growth of pathogenic bacteria and improve the quality of minced pork (Zhang et al. 2009).
Additionally, strong antimicrobial activity was observed from individual extracts of clove, rosemary, cassia bark and liquorice; and even a synergistic effect was achieved from the mixture of rosemary and liquorice extracts against L.
monocytogenes, E. coli, Ps. fluorescens and Lactobacillus sake. in modified atmosphere-packaged fresh pork and vacuum-packaged ham slices stored at 4ºC (Zhang et al. 2009). Recent studies regarding spice extract antimicrobial activity in meat products are summarized in Table 2.8.
On the other hand, spice and herbs extracts demonstrated a strong antioxidant property that positively influences meat quality characteristics by preventing lipid and pigment oxidation thus appears to be an alternative to synthetic additives in the meat industry (Deligeorgis and Simitzis 2010).
The vast majority of lipid oxidation is represented by deterioration of flavour, colour, texture, and nutritional value of food (Kanner 1994a). Thus, natural plant material (e.g. herbs and spices) have been used as potential antioxidants to maintain the quality of meat products (Zhang et al. 2010) (Table 2. 9).
According to Shan et al. (2005), the phytochemicals compounds including phenolic diterpenes, flavonoids, tannins and phenolic acids that present in spice and herbs composition are the potential sources of natural antioxidants.
Frankel (1998) indicated that antioxidant components work by a variety of different mechanisms, including the control of both oxidation substance (e.g.
oxygen and lipid) and prooxidants (e.g. reactive oxygen species and prooxidant metals) and the inactivation of free radicals.
McClements (2005), reported that antioxidant compounds can be divided into two groups depending on the mechanism by which they operate:
Primary antioxidants (chain-breaking antioxidant) retard lipid oxidation due to
their ability to accept free radicals, hence either retarding the initiation step or interrupting the propagation step (McClement and Decker 2000, Chaiyasit et al. 2007).
The ability of antioxidant (AH) to react with lipid radicals (peroxyl radicals (LOO•), alkoxyl radical (LO•) and free radical (L•)) as follows:
LOO• + AH → LOOH + A•
LO• + AH → LOH + A•
L• + AH → LH + A•
Antioxidant radicals (A•) are also able to participate in termination reactions with other antioxidant radicals or lipid radicals to form non radical species as follows.
LOO• + A• → LOOA LO• + A• → LOA L• + A• → LA A• + A• → AA
Secondary antioxidant retard lipid oxidation through a range of mechanism such as chelating of transition metal, oxygen scavenging and deactivation of reactive species (Reische et al. 1998, Trojakova et al. 2001).
Table 2.8: List of studies reporting the antibacterial activity of spice extracts and their application to meat products.
Meat product Spice extracts Concentration used
Target bacteria Source Minced beef Coriander and
Hyssop
0.02% v/w Enterobacteriaceae Michalczyk et al. 2012)
L. monocytogenes (Zhang et al.
2009) Ground beef Garlic, ginger,
and turmeric Beef fillets Oregano oil 0.8% L. monocytogenes (Tsigarida et
al. 2000)
Table 2.9: List of studies reporting the antioxidant activity of spice extracts (TBARS) and their application to meat products.
Meat product Spice extracts Concentration Used Raw pork batters Rosemary and
Oregano