Use of the scanning electron microscopy in the food industry - Research Paper Example

?  Use of the scanning electron microscopy in the food industry  Use of the scanning electron microscopy in the food industry Introduction Scanning electron microscopy (SEM), as well as other techniques such as energy dispersive spectroscopy (EDS) is an effective tool used for the identification and characterization of particulate contamination and foreign body contamination of food. Whether foreign body contamination occurs during processing or packaging, identification of these foreign bodies needs to be rapid and efficient in order to trace the source of contamination. The capabilities of SEM in foreign body identification make the process quite valuable to the food industry. The food industry operates in a spectrum that requires utmost cleanliness and absence of contamination. In essence, the discovery, as well as identification of foreign bodies in food compounds, is a vital activity, which contributes to overall food safety and the assurance of food quality (Smith, 1993). The incident of foreign bodies in food compounds and products can produce a number of dire consequences, which range from process down-time, to consumer complaints that negate an organization’s reputation, to expensive product recalls or litigation. This paper will examine the use of scanning electron microscopy in the food industry discussing its effectiveness in detecting and identifying foreign bodies in food compounds and products. Background In the US, the FDA keeps a close eye on product recalls and categorizes the severity of risks posed by food contaminants. For example, foreign body contamination such as through metal particles or glass fragments, warrants a Class II product recall, which refers to a situation where exposure or ingestion of violative products could cause temporary or medically reversible negative health implications (Vierk, Falci, Wolyniak & Klontz, 2002). Notably, product recalls within the food industry are not infrequent events. One of the most prominent product recalls occurred in May 2001 when at least 5,400 32oz jars of crispy sauerkraut were recalled as a result of suspected presence of glass fragments. Contamination of food products through foreign bodies, which are also hazardous allergens, for instance, peanuts warrants Class I recall characterized by the potential for dire threats to consumers’ health, probably resulting in death. Recalls related to allergen threats represent at least 36% of all recalled food products. In other countries such as the UK, nearly half of prosecutions related to food faults have been linked to contamination with foreign matter. In the UK, between 1988 and 1994, foreign matter contamination accounted for the largest grounds for defect prosecutions (Graves, Smith & Batchelor, 1998). These instances are viable indicators of the seriousness of food contamination in the food industry. Particulate contamination of food in the industry can occur from various sources. Prior to food purchase, this could include processing issues, for instance, wear particles form conveyors or breakages in the processing plants. Packaging materials, as well as interactions during the storage process, are also noteworthy sources of contamination. Notably, contamination of food products can also occur through parts of the food product, for instance, bone chips found in meat products. According to Lewis (1993) despite quality assurance measures established by food manufacturing and retail stakeholders, contamination can take place subsequent to product purchase within consumers’ homes. Deliberate contamination also occurs for purposes of sabotage or nuisance. Therefore, the detection of foreign bodies in food substances is a critical part of quality assurance and deterring adverse health occurrences in consumers. This detection relies on a variety of established techniques, which include among others X-rays, metal detection and ultrasound (H?ggstrom & Luukkala, 2001). Despite the mode of detection, whenever foreign matter is found in food, two principal questions emerge; what is it? and what is its source? There is a pressing need to find responses to these questions rapidly. The process of identifying particulate contamination could involve various techniques that range from light microscopy to specialized techniques such as SEM (Smith, 1993). This may require the expertise of food technologists, entomologists, materials scientists and biologists among others. After material identification, the next step is usually source identification where investigators draw a list of plausible contamination sources and deduce the source before analysis to narrow the process and hasten the results. Contaminant Identification All food manufacturers have quality assurance procedures, which guide the process of foreign matter detection and what occurs after such detection. The outset of these procedures typically involves optical examination documentation and macrophotography. This process provides vital information, which will ultimately determine subsequent treatment. Food manufacturers use scanning electron microscopy after light microscopy. In certain cases, the use of SEM is the first step in contaminant identification (Stasny, Albright & Graham, 1981). This is particularly because of the simplicity of sample preparation, as well as ease of interpretation inherent in SEM images. Increasing ease of accessibility to SEM instruments, for instance through University laboratory that offer investigative commercial services also places SEM in the initial stage of contaminant identification. Food manufacturers appreciate the need to understand the operation of SEM so as to prepare samples correctly and interpret results effectively. In scanning electron microscopes, beams of electrons interrelate with the samples through various ways. Because of the nature of the electron beam, the capacity and depth of an SEM is far stronger than that of a light microscope. Therefore, SEM allows for the viewing of an entire particle at the same time. Furthermore, the resolution capacity of an SEM allows for extensive magnifications of up to 1.5nm (Tatsumi, Watada & Wergin, 1991). SEM operators in the food industry have sufficient expertise to detect and identify food contaminant particles correctly. SEM is particularly vital in the food industry since it has the capacity to reveal the processing route of the product’s processing. For instance, available literature points to one incident in which a complainant detected the presence of a mouse in a certain food product (Lewis, 1993). Although the complainant suggested that the manufacturers had cooked the mouse with the product, an SEM was able to assess the morphology of the cooked mouse meat. The SEM investigator noted that the morphology of cooked mouse meat resulted in distinctive collagen breakdown. Upon investigation of the contaminant mouse, the investigator found that the dead mouse’s collagen was intact; therefore, the mouse was raw meaning it had not been processed with the food product (Charbonneau, 2001). Perhaps the greatest advantage of SEM in the food industry lies in its ability to analyze particles for the purposes of elemental composition while simultaneously imaging the particles through energy dispersive spectroscopy (EDS). Tatsumi, Watada and Wergin, (1991) conducted research in which they discovered the effectiveness of SEM in detecting the cause of contamination of a food substance (carrot sticks). The researchers prepared carrot sticks used sharp knives and noted that the carrots exhibited whitish, translucent appearances on the surfaces. The researchers utilized SEM to examine the emergent translucent tissue and noted that the sharp knives often shore, separated and compressed the tissues and cells of the root. Therefore, the SEM analysis showed that dehydration of the sizeable mass of exposed cells was attributable for the onset of the whitish, translucent tissue. The researchers focused on the study since the development of the whitish, translucent substance was undesirable since customers typically associate the condition with non fresh or aged carrot sticks. Charbonneau (1998) found that SEM and x-ray microanalysis are effective in the conduct of forensic investigations regarding glass and metal foreign objects in food. He argues that the method is excellent in the identification and recognition of metal foreign matter in food, for instance, dental filings, wires, metal packaging and bone, depending on the substances’ element composition. SEM is used in the food industry to determine the degree of corrosion of metallic foreign objects. SEM allows food manufacturers to assess corrosion degrees on metals in order to determine whether or not the metals were processed with the food substances and products. Charbonneau (1998) discusses case histories of unprocessed nickel-coated steel, corrosion resistant steel and processed aluminum found in food products. In one of the studies, SEM investigators used SEM to resolve a potential product-tampering issues concerning a hole defect in a paperboard package. SEM investigations were effective in finding blue fibers in the holes. These blue fibers contained brass particles emanating from ball point pens rather than syringe needles. This study is indicative of how SEM can effectively differentiate and delineate various elemental compositions to ascertain the source of contamination. For instance, through SEM, food industries can ascertain elemental compositions of glass foreign objects and distinguish between various forms of glass such as bakeware, electrical and container. The researchers found that SEM can effectively distinguish glass-like foreign matter from glass, which form foreign body contaminants in food products. Charbonneau further discusses the effectiveness of SEM in case histories concerning the discovery and identification of struvite crystals in salmon and tartar cream crystals, in grape juice. Conclusion This paper has provided a succinct examination of the use of SEM in the food industry noting that the process of SEM analysis continues to offer substantive capabilities for the food industry to ensure product quality. Food industries, these days have particles whose size ranges from micrometer to nanometer. SEM has the capacity to distinguish particles in high magnifications and resolutions thereby enabling food manufacturers and processors to detect and identify foreign matter in food products. Methodical and systematic approaches to analysis primarily offer the fastest, as well as most economic approach for the identification of foreign body contamination and other substances in food. These are iterative processes in which investigators perform tests until they concisely identify the contaminant material. In cases where the character of the complaint is exact, for instance, during court cases, contaminant identifications become quite imperative (Philips & Bertraud, 1976). When utilized in combination with conventional quality assurance techniques, SEM proves to be a powerful and immensely effective tool for the identification of particulate contamination if food. Correct identification of foreign body contamination as efficiently, accurately and economically as possible allows the integration of analytic techniques of microscopists and process knowledge of quality assurance personnel in the food industry. References Charbonneau, J. E. (1998). Investigation of foreign substances in food using scanning electron microscopy-x-ray microanalysis. Scanning, 20(4), 311-317. Charbonneau, J. E. (2001). Investigation of foreign substances in food. Scanning, 23, 51-57. Graves, M., Smith, A., & Batchelor, B. (1998). Approaches to foreign bodies’ detection in foods. Trends in Food Science and Technology, 9, 21-27. H?ggstrom, E., & Luukkala, M. (2001). Ultrasound detection and identification of foreign bodies in food products. Food Control, 12, 37-45. Lewis, D. F. (1993). A tutorial and comprehensive bibliography on the identification of foreign bodies found in food. Food Structure, 12, 365-378. Philips, J. G., & Bertraud, W. S. (1976). The identification of foreign matter in food. Food Technology New Zealand, 11(1), 42-43. Smith, W. F. (1993). Foundations of materials science and engineering (2nd ed.). New York: McGraw-Hill. Stasny, J. T., Albright, F. R., & Graham, R. (1981). Identification of foreign matter in foods. Scanning Electron Microscopy, 3, 599-610. Tatsumi, Y., Watada, A. E., & Wergin, W. P. (1991). Scanning electron microscopy of carrot stick surface to determine cause of white translucent appearance. Journal of Food Science, 56(5). Vierk, K., Falci, K., Wolyniak, C., & Klontz, K. C. (2002). Recalls of foods containing undeclared allergens reported to the US Food and Drug Administration, fiscal year 1999. Journal of Allergy and Clinical Immunology, 109(6), 1022-1026. . Read More