12 Joseph H.Hulse Trends in Food Science Technology 15(2004)3-18 properties among all production runs.Specifications are name 'Enzyme linked immunosorbent assays'(ELISA). laid down by (1)international protocols,(2)govern- Automated ELISA systems are based on a dipstick ment regulatory agencies,(3)customers,secondary technology originally developed for testing pregnancy in processors and retailers;(4)processing company man- women. agers.Specifications,analyses and assessments of foods An ideal sensor must be accurate,reliably responsive, and drugs are designed to ensure safety to consumers and robust and tolerant to processing conditions,easy to effectiveness within the conditions prescribed for use. install and maintain,inexpensive in relation to product More than 8000 processed foods and 7000 approved market value.Magnetic Resonance Imaging (MRI)and drugs are commercially produced in North America and other expensive systems are economic for pharmaceu- Europe,together with unknown quantities of traditional tical but generally too expensive for most industrial foods and drugs on other continents.A comprehensive food processes. account of all recommended and tentative QC proce- On-line control systems are as much the responsibility dures would fill many CD Roms.This paper offers only of production bioengineers as of quality control bio- an overview of present trends and practices.Bioengi- chemists and microbiologists.Many on-line sensors and neers must ensure that materials of construction are probes determine a reaction or response indirectly rela- compatible with biological materials to be processed. ted to the property critical to product safety and effec- Processing equipment must be easy to clean and,where tiveness.Bioengineers must therefore comprehend the necessary,to sterilize. relation between the response recorded and the critical product property to be determined.Sensors and their On-line systems responses should be systematically checked and correlated Analyses of random samples from finished products with direct methods of determination. in a quality control laboratory is gradually being superseded by control systems that use on-line sensors, Quality control(QC)and genetically modified (GM) probes and monitors that continually assess critical organisms properties.When a defective property is identified,a The use of living organisms to synthesize pharmaceu- feed-back signal corrects the faulty processing para- ticals,the complexity of the process technologies,call meter,all on-line determinations being recorded in a for changing patterns of process and product control.In computer. addition to ensuring product safety and effectiveness, More than 100 devices determine flow rates,apparent control systems must characterize and monitor organisms viscosities and various rheological properties.Others used,cell culture conditions,reaction,recovery and pur- record temperature,pressure and RH gradients.Various ification processes.OC of biologicals produced by viruses critical properties are assessed by change in electrical microbial,plant,insect and mammalian cells is more com- conductivity or dielectric constant.Chemical sensors plicated than of pharmaceutical substances isolated from respond to changes in pH,specific ions,organic radicals medicinal plants or synthesized by chemical reactions. and impurities.Biosensors employ immobilized bac- Accurate analysis of novel proteins synthesized by teria,enzymes,antigen-antibody reactions and DNA rDNA in GM organisms is an important priority.Pro- probes.By multivariant analysis of responses to mixed gress is evident in automation of electrophoresis,amino aromatics,an electronic nose can detect desirable or acid analysis and gene sequencing.HPLC coupled with obnoxious odours mass spectrometry and immunochemistry is extending Spectroscopic on-line methods are too many and the frontiers of protein analysis.Robotics,though rela- diverse to be catalogued.Ultrasonics detect particle size tively slow,are useful for tedious activities such as iso- distribution,emulsion breakdown and various adulter- tope labelling.Of urgent need are reliable methods to ants.Near infra-red can be calibrated to determine determine picogram levels of possible oncogenic DNA moisture,protein,lipid and various other component in mammalian cell cultures. concentrations.Magnetic resonance imaging is an advanced spectroscopic method based on different The future of bioengineering magnetic properties of atomic nuclei when placed in a From the data provided by the Ernst and Young magnetic field.The field induces different energy levels regional biotechnology studies,from other publications between protons aligned with and protons aligned and discussions with biotech industry executives,it is against the field.MRI,most widely used to diagnose clearly evident that the demand for bioengineers and defects in the human body,now is applied to detect biotechnologists exceeds present and predicted supply. infections in aseptically packaged foods and drugs. One study forecasts that over the next decade industrial Being non-destructive,it offers 100%inspection of opportunities for bioengineers will rise by 80%.for critical biological materials. research and development bioscientists by ca 60%. Immunological methods attach enzyme labels to Since the mid-1970s,modern biotechnology industries antibodies to react to specific pathogens,hence the have generated more than 100 new drugs and vaccinesproperties among all production runs. Specifications are laid down by (1) international protocols, (2) govern￾ment regulatory agencies, (3) customers, secondary processors and retailers; (4) processing company man￾agers. Specifications, analyses and assessments of foods and drugs are designed to ensure safety to consumers and effectiveness within the conditions prescribed for use. More than 8000 processed foods and 7000 approved drugs are commercially produced in North America and Europe, together with unknown quantities of traditional foods and drugs on other continents. A comprehensive account of all recommended and tentative QC proce￾dures would fill many CD Roms. This paper offers only an overview of present trends and practices. Bioengi￾neers must ensure that materials of construction are compatible with biological materials to be processed. Processing equipment must be easy to clean and, where necessary, to sterilize. On-line systems Analyses of random samples from finished products in a quality control laboratory is gradually being superseded by control systems that use on-line sensors, probes and monitors that continually assess critical properties. When a defective property is identified, a feed-back signal corrects the faulty processing para￾meter, all on-line determinations being recorded in a computer. More than 100 devices determine flow rates, apparent viscosities and various rheological properties. Others record temperature, pressure and RH gradients. Various critical properties are assessed by change in electrical conductivity or dielectric constant. Chemical sensors respond to changes in pH, specific ions, organic radicals and impurities. Biosensors employ immobilized bac￾teria, enzymes, antigen-antibody reactions and DNA probes. By multivariant analysis of responses to mixed aromatics, an electronic nose can detect desirable or obnoxious odours. Spectroscopic on-line methods are too many and diverse to be catalogued. Ultrasonics detect particle size distribution, emulsion breakdown and various adulter￾ants. Near infra-red can be calibrated to determine moisture, protein, lipid and various other component concentrations. Magnetic resonance imaging is an advanced spectroscopic method based on different magnetic properties of atomic nuclei when placed in a magnetic field. The field induces different energy levels between protons aligned with and protons aligned against the field. MRI, most widely used to diagnose defects in the human body, now is applied to detect infections in aseptically packaged foods and drugs. Being non-destructive, it offers 100% inspection of critical biological materials. Immunological methods attach enzyme labels to antibodies to react to specific pathogens, hence the name ‘Enzyme linked immunosorbent assays’ (ELISA). Automated ELISA systems are based on a dipstick technology originally developed for testing pregnancy in women. An ideal sensor must be accurate, reliably responsive, robust and tolerant to processing conditions, easy to install and maintain, inexpensive in relation to product market value. Magnetic Resonance Imaging (MRI) and other expensive systems are economic for pharmaceu￾tical but generally too expensive for most industrial food processes. On-line control systems are as much the responsibility of production bioengineers as of quality control bio￾chemists and microbiologists. Many on-line sensors and probes determine a reaction or response indirectly rela￾ted to the property critical to product safety and effec￾tiveness. Bioengineers must therefore comprehend the relation between the response recorded and the critical product property to be determined. Sensors and their responses should be systematically checked and correlated with direct methods of determination. Quality control (QC) and genetically modified (GM) organisms The use of living organisms to synthesize pharmaceu￾ticals, the complexity of the process technologies, call for changing patterns of process and product control. In addition to ensuring product safety and effectiveness, control systems must characterize and monitor organisms used, cell culture conditions, reaction, recovery and pur￾ification processes. QC of biologicals produced by viruses, microbial, plant, insect and mammalian cells is more com￾plicated than of pharmaceutical substances isolated from medicinal plants or synthesized by chemical reactions. Accurate analysis of novel proteins synthesized by rDNA in GM organisms is an important priority. Pro￾gress is evident in automation of electrophoresis, amino acid analysis and gene sequencing. HPLC coupled with mass spectrometry and immunochemistry is extending the frontiers of protein analysis. Robotics, though rela￾tively slow, are useful for tedious activities such as iso￾tope labelling. Of urgent need are reliable methods to determine picogram levels of possible oncogenic DNA in mammalian cell cultures. The future of bioengineering From the data provided by the Ernst and Young regional biotechnology studies, from other publications and discussions with biotech industry executives, it is clearly evident that the demand for bioengineers and biotechnologists exceeds present and predicted supply. One study forecasts that over the next decade industrial opportunities for bioengineers will rise by 80%, for research and development bioscientists by ca 60%. Since the mid-1970s, modern biotechnology industries have generated more than 100 new drugs and vaccines. 12 Joseph H. Hulse / Trends in Food Science & Technology 15 (2004) 3–18