Impact of material and processing equipment on establishment and persistence of pathogens associated with foodborne illness

Published on:
Author/s :

Introduction

Bacterial foodborne pathogens such as Salmonella (Hood and Zottola, 1997), Campylobacter (Nguyen et al., 2012), Arcobacter (Gibrau et al., 2017) and Listeria (Sofyan et al., 2006) have the ability to attach to processing equipment materials, and subsequently equipment contact surfaces may lead to bacterial contamination of poultry meat during processing (Giaouris et al., 2013). Therefore, poultry processing equipment must be designed, constructed and maintained to meet minimal sanitary criteria. These minimal criteria include: 1. Impermeable to water; 2. Resistant to wear and corrosion; and 3. Facilitated cleaning and sanitizing (Hubbert and Hagstad, 1991). While use of materials that meet entail these criteria have been a longterm practice by the poultry processing.

industry, recent foodborne disease outbreaks and food recalls in which the contaminant originated from the processing environment continue to emphasize the importance or preventing equipment surfaces from becoming contamination sources.

In regards to preventing processing equipment from becoming chronic sources of bacterial contaminants, there is an increasing emphasis on the sanitary design and materials used particularly in regards to decreasing or preventing bacterial attachment. The phenomenon of bacterial attachment to surfaces is complex and not fully understood. It is known that many factors including physiological state of bacterial cells and the physiochemical properties of the surfaces affect initial attachment (Goulter-Thorsen et al., 2011; Hui and Dykes, 2012; Mai and Conner, 2007; Nguyen et al., 2012). To reiterate, it is recognized that foodborne pathogens, once attached to food processing surfaces, can persist for extended periods and serve as a source of contamination in final products (Berrang et al., 2010; Berrang and Frank, 2012; Martin et al., 2011; Sakaridis et al., 2011; Spurlock and Zottola, 1991). Therefore, a better understanding of the role of processing equipment materials on attachment, establishment, and persistence of foodborne bacterial pathogens can lead to better control methods and improved food safety.

Stainless Steel

Austenitic stainless steels are the predominant materials used in a wide variety of poultry processing equipment (Spragg, 1977) because they are generally nonreactive, easily cleaned and corrosion resistant (Holah and Thorpe, 1990; Masurovsky and Jordan, 1958). Surface finish can be of great importance to the hygiene of stainless steel food contact surfaces; therefore, roughness standards have been established for stainless steel intended for food contact. (BoulangePetermann,1996). In response to increased concern over post-process contamination for ready-to-eat products, recent research has focused on the effects of stainless steel roughness and other surface properties on the initial attachment of microorganisms.

Sofyan et al. (2006) determined the attachment of Listeria monocytogenes to stainless steel 304 finished to No. 2B (mill), No. 4 (satin) and No. 8 (mirror) standards, and reported that cells attached at a greater rate to the mirror finished stainless steel as compared to the other two finishes, and more bacteria attached to the satin stainless steel vs the mill finished steel. GoulterThorsen et al. (2011) obtained similar results using Escherichia coli O157, although bacteria were more easily removed from mirror finished steel and attachment results were inconsistent on No. 4 finished stainless steel. In general, it is difficult to draw a direct correlation between surface physical properties (i.e., roughness, contact angle, etc.) and ability of bacteria to initially attach. Medilanski et al. (2002), found that bacterial attachment to stainless steel surfaces may not be related to surface roughness alone, but rather to the differences in surface topography or other factors. Attachment of Salmonella and Campylobacter to stainless steel also appears to be complex and dependent on factors beyond surface roughness (Giaouris et al., 2012; Nguyen et al., 2012).

Any disruption of a stainless steel’s food-grade finish can lead to a loss of cleanability and promote bacterial harborage sites. While stainless steel processing surfaces are typically welded during original manufacture, the weld areas are polished to a food-grade finish prior to installation (National Sanitation Foundation, 2000). This polishing is critical because welding can delete chromium from the weld zone, which causes a loss of corrosion-resistance. Without proper post-welding treatment, corrosion can occur in the weld region and corroded metal can harbor bacteria. Mai et al. (2006) reported that welding of austenitic stainless steel followed by polishing did not affect bacterial attachment; however, corrosion of welded stainless steel promoted bacterial attachment. Thus, processors who weld stainless steel for repairs and modifications should utilize welding techniques or post-welding treatments that minimize subsequent corrosion.

Other Materials and Consideration for the Poultry Processing Plant

Within a poultry processing plant, there are numerous contact and non-contact surfaces to which bacteria can attach and persist. Again, these surfaces need to meet the minimum sanitary criteria stated above (Hubbert and Hagstad, 1991). Arnold and Silvers (2000) investigated attachment of mixed bacteria to variety of materials found in poultry processing, including stainless steel, conveyor belting, polyethylene and picker-finger rubber. These researchers reported that while variation in affinity was observed, bacteria attached to steel, belting and polyethylene. However, attachment of the test bacteria was inhibited by the picker-finger rubber. Veluz et al. (2012) determined the attachment of Salmonella and L. monocytogenes to materials commonly used for poultry processing conveyor belts, including polyurethane with monopolyester fabric, acetal, polypropylene-meshtop, polypropylene, stainless steel single loop, and stainless steel balance weave. For both tested bacterial cultures attachment to all tested materials was observed; however, stainless steel was more resistant to attachment as compared to the plastic materials.

While surfaces that contact poultry during processing are of primary concern for cleanability and sanitation, non-contact surfaces may also harbor foodborne pathogens. Therefore, materials employed for use in poultry processing plant structures are also of concern from a food safety standpoint. For example, cast iron has be used for floor draining for many years. Spurlock and Zottola (1991) demonstrated the ability of L. mononcytogenes to attach and form biofilms on cast iron surfaces, and concluded that floor drains could be a reservoir of this pathogen in food processing facilities. Additionally, walls, floors and ceilings can serve as sources of chronic bacterial contamination in food processing. Concrete, widely used in poultry processing environments, may be permeated with bacteria due to its microporous structure (Yang et al., 2004). Concrete floors, walls and ceilings in food processing environments typically are sealed with a waterproof treatment; however, sealants can be easily damaged or eroded over time or the concrete may crack. Exposed concrete and cracks provide bacterial harborages that can lead to chronic sources of environmental contamination of food products (Hubbert and Hagstad, 1991). Paiva et al. (2009, 2010) reported that a novel concrete sealant, a hydrosilicate catalyst in a colloid liquid base, reduced attachment of Salmonella spp. and Listeria spp. to concrete, and that the sealant prevented Salmonella spp. from penetrating into the structure of the concrete. In contrast Listeria spp. were recovered from the interior of inoculated concrete, which suggest that Listeria spp. exhibited the ability to penetrate into the microporous structure. When comparing results these researchers obtained with Salmonella spp. and Listeria spp., it appears that bacterial penetration of concrete microstructure is dependent on type of bacteria. Although the tested sealant did not prevent penetration of Listeria spp. into the concrete, it significantly reduced exterior and interior Listeria spp. when applied after bacterial inoculation. These researchers suggested that this tested concrete sealant had potential to reduce environmental Salmonella and Listeria when used in combination with other sanitation procedures.

Summary

Controlling product contamination during processing is a major food safety goal for all poultry processors. Use of hygienically designed, installed and maintained equipment is a sound strategy for helping achieve this goal. Materials used in the construction of processing plants also play a role in the establishment and persistence of environmental foodborne pathogens; therefore, the physical structure of the processing plant must be constructed in using proper materials and design. Recent research provides valuable information that poultry processors, equipment manufacturers and facility designers may use to enhance control of bacterial contaminants.


Presented at the XXV Latin American Poultry Congress in Guadalajara, Mexico.


References

ARNOLD, J. and SILVERS, S. (2000) Comparison of poultry processing equipment surfaces for susceptibility to bacterial attachment and biofilm formation. Poultry Science 79: 12151221.

BERRANG, M.E. and FRANK, J.F. (2012) Generation of airborne Listeria innocua from model floor drains. Journal of Food Protection 75: 1328-1331.

BERRANG, M.E., MEINERSMANN, R.J., FRANK, J.F. and LADELY, S.R. (2010) Colonization of a newly constructed commercial chicken further processing plant with Listeria monocytogenes. Journal of Food Protection 73: 286-291.

BOULANGE-PETERMANN, L. (1996) Processes of bioadhesion on stainless steel surfaces and cleanability: a review with special reference to the food industry. Biofouling 10: 275-300.

GIAOURIS, E., CHORIANOPOULOS, N., SKANDAMIS, P. and NYCHES, G-J. (2012) Attachment and biofilm formation by Salmonella in food processing environments, Salmonella – a dangerous foodborne pathogen. Mahmoud, B.S.M. (Ed.), ISBN 978-953307-782-6, InTech, Available from: http://intechopen.com/books

GIAOURIS, E., HEIR, E., HEBRAUD, M., CHORIANOPOULOS, N., LANGSRUD, S., MORETRO, T., HAMIMANA, O., DESVAUX, M., RENIER, S. and NYCHES, G-J. (2013) Attachment and biofilm formation by foodborne bacteria in meat processing environments: causes, implications, role of bacterial interactions and control by alternative novel methods. Meat Science 97: 298309.

GIRBAU, C., MARTINEZMALAXETXEBARRIS, I., MURUAGA, G., CARMONA, S., ALONSO, R. and FERNANDEZ-ASTORGA, A. (2017) Study of biofilm formation ability of foodborne Arcobacter butzleri under different conditions. Journal of Food Protection 80: 758-762.

GOULTER-THORSEN, R.M., TARAN, E., GENTLE, I.R., GOBIUS, K.S. and DYKES, G.A. (2011) Surface roughness of stainless steel influences attachment and detachment of Escherichia coli O157. Journal of Food Protection 74: 1259-1363.

HOLAH, J.T. and THORPE, R.H. (1990) Cleanability in relation to bacterial retention on unused and abraded domestic sink materials. Journal of Applied Bacteriology 69: 599-608.

HOOD, S.K. and ZOTTOLA, E.A. (1997) Adherence to stainless steel by foodborne pathogens during growth in a model food system. International Journal of Food Microbiology 37: 145-153.

HUBBERT, W.T. and HAGSTAD, H.V. (1991) Food Safety and Quality Foods of Animal Origin, pp. 29-31 (Ames, Iowa, Iowa State University Press).

HUI, Y.W. and DYKES, G.A. (2012) Modulation of cell surface hydrophobicity and attachment of bacteria to abiotic surfaces and shrimp by Malaysian herb extracts. Journal of Food Protection 75: 1507-1511.

MAI, T.L. and CONNER, D.E. (2007) Effect of temperature and growth media on the attachment of Listeria monocytogenes to stainless steel. International Journal of Food Microbiology 120: 282-286.

MAI, T.L., SOFYAN, N.I., FERGUS, J.W., GALE, W.F. and CONNER, D.E. (2006). Attachment of Listeria monocytogenes to an austenitic stainless steel after welding and accelerated corrosion treatments. Journal of Food Protection 69: 1527-1532.

MARTIN, B., GARRIGA, M. and AYMERICH, T. (2011) Prevalence of Salmonella spp. and Listeria monocytogenes at small-scale Spanish factories producing traditional fermented sausages. Journal of Food Protection 74: 812-815.

MASUROVSKY, E.B. and JORDAN, K.W. (1958) Studies on the relative bacterial cleanability of milk contact surfaces. Journal of Dairy Science 41: 1342-1358.

MEDILANSKI, E.K., KAUFMANN, K. WICK, L.Y., WANNER, O., and HARMS, H. (2002) Influence of the surface topography of stainless steel on bacterial adhesion. Biofouling 18: 193203.

NATIONAL SANITATION FOUNDATION (2000) Hygienic requirements for the design of meat and poultry processing equipment. ANSI/NSF/3-A 14159-1-2000. NSF International, Ann Arbor, MI.

NGUYEN, V.T., FEGAN, N., TURNER, M.S. and DYKES, G.A. (2012) Role of attachment to surfaces on the prevalence and survival of Campylobacter through food systems. Journal of Food Protection 75: 195-206.

PAIVA, D.M., MACKLIN, K.S., PRICE, S.B., HESS, J.B., CONNER, D.E. and SINGH, M. (2010) Efficacy of a commercial concrete sealant against Listeria spp. a model for poultry processing facilities. Journal of Applied Poultry Research 19: 146-151.

PAIVA, D.M., SINGH, M., MACKLIN, K.S., PRICE, S.B., HESS, J.B. and CONNER, D.E. (2009) Antimicrobial activity of commercial concrete sealant against Salmonella spp. a model for poultry processing plants. International Journal of Poultry Science 8: 939-945.

SAKARIDIS, I., SOULTOS, N. IOSSIFIDOU, E., PAPA, A., AMBROSIADIS, I., and KOIDIS, P. (2011) Prevalence and antimicrobial resistance of Listeria mononcytogenes isolated in chicken slaughterhouses in northern Greece. Journal of Food Protection 74: 1017-1021.

SOFYAN, N.I., MAI, T.L., CONNER, D.E., FERGUS, J.W., and GALE, W.F. (2006) Attachment of Listeria monocytogenes to an austenitic stainless steel with three different types of surface finish. Food Protection Trends 26: 926-929.

SPRAGG, J.D. (1977) Handbook of stainless steels. New York, McGraw Hill.

SPURLOCK, A.T. and ZOTTOLA, E.A. (1991) Growth and attachment of Listeria monocytogenes to cast iron. Journal of Food Protection 54: 925-929.

VELUZ, G.A., PITCHIAH, S. and ALVARADO, C.Z. (2012) Attachment of Salmonella servovars and Listeria mononctogenes to stainless steel and plastic conveyor belts. Poultry Science 91: 2004-2010.

YANG, C.C., WANG, L.C. and WENG, T.L. (2004) Using charge passed and total chloride content to assess the effect of penetrating silane sealer on the transport properties of concrete. Materials Chemistry and Physics 85: 238244.

 
Author/s
 
remove_red_eye 209 forum 0 bar_chart Statistics share print
Share :
close
See all comments
 
   | 
Copyright © 1999-2019 Engormix - All Rights Reserved