Agriculture Reference
In-Depth Information
Despite continued efforts are devoted to control crop and food pathogens,
microbiological safety threats prevail, and therefore, the investigation for methods
to detect and control harmful microorganisms is constant. The most common
preservation strategies applied in the food industry involve chemical or physical
techniques. Several strategies have been used to extend the shelf life of vegetables
and food, including heat treatments, infrared or microwave irradiation, using
modified atmospheres during packaging, by adding chemical preservatives (e.g.,
sorbic, benzoic, and propionic acids), or emerging technologies such as pulsed
electric field and high-pressure processing (Sun
2005
). However, these methods
only decrease microbial infections and often fail to completely eliminate microbial
contaminants. Also, some fungi and bacteria are able to adapt to the presence of
certain preservatives (Davidson and Harrison
2002
). In addition, current consumer
trends are increasingly demanding high-quality fresh vegetable products with
extended shelf life and foods that are free of chemical pesticides. This last feature
is an important aspect to consider when discussing the need for new preservation
methods to inhibit the growth of undesirable contaminating microorganisms and is
motivating the food industry toward a focus on natural preservation approaches
(Cabral et al.
2013
; Zheng et al.
2013
). Biopreservation technologies are being
favored to improve the safety, the nutrition value, and the organoleptic properties,
in response to consumer demands. The fermentation by lactic acid bacteria has been
used in food production to antagonize spoilage contaminants and is increasing in
popularity due to their ability to enhance either the product quality or its nutritional
profile (Gerez et al.
2013
; Oliveira et al.
2014
). In this context, the use of
nanostructures for more efficient delivery of natural antimicrobials constitutes a
real alternative to combat microbial spoilage and pathogenic microorganisms in
crops and foods (Malheiros et al.
2010a
; Gomes et al.
2011
).
6.3 Nanostructures for Antimicrobial Delivery
Nanobiotechnology may represent a new paradigm in the development of nano-
structured materials for antimicrobial delivery in agricultural sciences. A rising
number of peer-reviewed publications are available on the investigation of
nanopesticides, mainly devoted to insecticides (about 55 %) followed by fungicides
(about 30 %). This greater proportion of insecticidal formulations may be associ-
ated with the limited water solubility of many conventional insecticides and with
the possibility of using alternative ingredients that are less harmful to nontarget
organisms and to the environment (Kah and Hofmann
2014
). Some major
nanostructures related to antimicrobial delivery and examples of agriculture and
food applications are presented in the sequence.
