Food Protection Trends - March/April 2023 - 137

antimicrobial properties can more easily be maintained in a
sanitary state. Similar to innovative sanitation technologies,
research on antifouling and antimicrobial surfaces has
mainly focused on equipment used in food processing and
manufacturing. Several reviews have been recently published
that have summarized and explained the various innovative
materials and methods and the unique challenges in food
industry applications (11, 44, 128).
Innovative antimicrobial and antifouling materials
include additives incorporated into the structural materials
themselves, modified material surfaces, or surface coatings
that have antibacterial activity (antimicrobial) or that prevent
soil and bacterial adhesion (antifouling) (4, 8, 11, 31, 40,
46-48, 56, 117, 172, 184). Chaitiemwong et al. (31) reported
enhanced L. monocytogenes reduction on wet conveyor
belt material containing antimicrobial additives compared
with wet conveyor belt material without additives. Ban et
al. (8) modified stainless steel by creating nanoscale pores
in the material surface coupled with a Teflon coating to
form a self-cleaning surface that reduced E. coli O157:H7
and Salmonella populations by 2.1 to 3.0 log CFU/cm2
,
respectively, compared with untreated or noncoated stainless
steel. Surface coatings range from permanent to temporary
(e.g., food-safe oil-based coatings) (4, 11). Awad et al. (4)
evaluated a food-safe oil-based slippery coating for stainless
steel surfaces and reported that the oil coating, which filled
surface grooves and cavities, suppressed bacterial adherence
and biofilm formation. Metal-based coatings such as
titanium, silver, copper, and zinc on food-contact surfaces
act as antimicrobials by reducing retention and enhancing
the removal of bacteria from the coated surfaces (11, 172).
Many antimicrobial coatings work in synergy with sanitizing
treatments, resulting in enhanced bactericidal effects (46,
47). Other coatings exploit material properties such as
hydrophobicity or hydrophilicity that inhibit or minimize
bacterial adhesion (56, 184). Rechargeable coatings
containing antimicrobial N-halamines (a halogenated
nitrogen compound) can renew their antimicrobial effect
by reloading from a halogen (chlorine, bromine, or iodine)
source (11). Cossu et al. (40) evaluated a novel rechargeable
antimicrobial polymer that prevents biofilm formation over
repeated exposures and helps inactivate existing biofilms
upon contact. The polymeric material is recharged with
bleach during cleaning with mechanical sonication. Although
few, if any, of these novel technologies are at a state where
they could be applied to preharvest equipment, this area may,
in the long term, yield approaches that could be valuable for
preharvest food safety.
CONCLUSION
Equipment and tools used in harvesting produce crops
can harbor and transfer human pathogens present in the
outdoor environment in which they operate. Environmental
conditions affect the risk of contamination by microbial
hazards in the produce production environment where the
equipment is operating. For example, numerous studies
have provided evidence that contamination risk is higher
when the soil is wet (i.e., after rainfall or irrigation). Use of
harvesting equipment in the field too soon after irrigation or
precipitation may increase the risk of cross-contamination.
The fast-paced, time-sensitive nature of harvesting produce
crops in an outdoor environment presents distinctive challenges
for maintaining equipment in a sanitary condition.
When food-contact and other exposed surfaces or internal
hollow areas on harvesting equipment frames and at fractures
in welded areas become contaminated, pathogens can
be transferred to harvested product. Research and development
efforts across industries are producing new, practical,
and cost-effective materials and techniques for maintaining
harvesting equipment in a sanitary state during and after use.
Equipment operators can take practical steps to minimize
cross-contamination between food-contact surfaces, areas
adjacent to food-contact surfaces, and the produce crops.
Cleaning and sanitizing equipment in a timely manner using
appropriate methods and techniques are the keys to preventing
microbial contamination of produce crops during harvesting
activities. Equipment operators should have a basic
understanding of the chemistry and mechanisms underlying
their sanitation processes and the efficacy of these treatments
against biofilms. Well-written SSOPs should provide
work crews with clear and concise instructions regarding
the methods and tools for cleaning and sanitizing harvesting
equipment. Although the FDA did not include monitoring
requirements in the Produce Safety Rule, harvesting companies
must validate equipment SSOPs and verify cleaning and
sanitation procedures as part of their food safety programs
and risk management strategies. When equipment is not
in use, the practicality of storage-covered or uncovered,
indoors or outdoors-to minimize the risk of contamination
is worth consideration.
Continued attention to equipment design and construction
and use of enhanced hygienic practices are also fundamental
to the produce industry's commitment to provide
consumers with safe, nutritious products. Applied research
on the efficacy of harvest equipment sanitation (e.g., with
various chemicals, for various dwell times, and under various
environmental conditions) will be valuable for establishing
cleaning and sanitation performance criteria and identifying
situations in which harvest equipment sanitation differs substantially
from findings for sanitation in other environments
(e.g., packinghouses and processing facilities).
March/April Food Protection Trends 137
Food Protection Trends - March/April 2023

Table of Contents for the Digital Edition of Food Protection Trends - March/April 2023
