Traceability of environmental conditions for maintaining

horticultural produce quality

 

 

Denyse LeBlanc¹* and Clément Vigneault²

¹Agriculture and Agri-Food Canada, Atlantic Food and Horticulture Research Centre, Université de Moncton, Moncton, New Brunswick, Canada.

² Agriculture and Agri-Food Canada, Horticulture Research and Development Centre, 430 Gouin BLVD., Saint-Jean-sur-Richelieu, Québec, Canada.

 

 

Abstract

Purpose of review: The purpose of this review is to present various monitoring systems that have been used recently or have the potential to trace environmental conditions surrounding perishable foods from the field to retail.

Findings: Numerous monitoring systems are commercially available to trace the temperature and some environmental conditions surrounding perishable foods in the supply chain. These measured parameters can be recorded with different systems in each segment of the supply chain. To obtain a complete history of the conditions surrounding a particular lot of fresh produce from field to retail display, one would need to obtain the histories recorded while the lot was in each segment of the supply chain. Although this type of pedigree will indicate whether or not a lot of fresh produce has been exposed to adverse conditions, it does not necessarily represent the temperature, the atmosphere composition or other condition of the produce itself. Systems that monitor the produce environment from field to retail can be integrated in the inventory management systems used by produce shippers, wholesalers and retailers. Portable data loggers are becoming smaller and more economical every year. When placed inside a unit of fresh produce (container, pallet, box, bag , etc.), loggers could record produce environmental conditions from packing right up to when the content of the unit is stacked in the retail display. Remote monitoring systems allow shippers to verify the condition of a lot of produce in transit, which is extremely useful for long-duration shipments. To effectively use these environmental condition histories, models need to be developed to predict the shelf-life remaining when a particular produce is exposed to specific conditions. Several researchers have tested various systems to determine their accuracy in predicting remaining shelf-life, however very few researchers have carried out this testing for fresh whole or fresh-cut produce. For example, radio frequency identification (RFID) labels that record temperatures are the ultimate traceability tool as they will be able to reconstruct the history of a produce from packing to retail display. However, the RFID labels need to have data on the time-temperature tolerance of each type of produce they must follow to be able to accurately indicate the change in microbial or sensory qualities of fresh produce that have occurred. Regardless of the type of traceability tool used (portable data logger, time-temperature integrators, RFID label, etc.), external condition tolerance data is required for all type of fruits and vegetables to optimise inventory management.

Limitations/implications: Although traceability of temperature already exists, only a few real commercial applications of tracing other environmental conditions exist. Thus, this review could not be limited to existing cases only. Scientific literature and industrial applications have been searched to highlight potential equipment used by horticulture and other industries, or through research activities and that could be used for monitoring and reporting all environmental conditions. Various companies manufacture systems that could be used to trace environmental conditions however, they may not have published articles on their systems. Therefore their system could not be reported here. This review is limited to what is available in the literature at the present time. Other systems might exist. The absence or the presence of any system should not be considered as a negative or positive comment about these systems.

Directions for future research: Enough knowledge is already available to design traceability systems for monitoring and reporting some environmental conditions of horticultural produce. However, although some technologies exist, it is clear that their full potential is not exploited nor explored. Many technologies could be applied to traceability systems for monitoring and reporting horticultural produce environmental conditions with little adaptation. Development of new types of affordable and precise sensors that could record environmental conditions for long periods and make this data available at any time is highly desirable. More research is required in this domain, but we are not starting at the very beginning so care should be taken to not reinvent procedures that are already available. Standardisation is also an important issue. Since traceability should be from the seed to the table, the compatibility between database and communication systems should be discussed on a national, if not international, basis. Individual companies should not decide to monitor and record their data based only on their own needs. Research, development and standardisation must be based on world need considerations. Great challenges exist for all those wanting to participate in the development of systems that trace the environmental conditions of horticultural produce, from the seed to the table.

 

Keywords: atmosphere; fruit; handling; monitoring systems; resonance; temperature; transportation; vegetable; vibration

 

 

Stewart Postharvest Review 2006, 3:4

Published online 01 June 2006

DOI: 10.2212/spr.2006.3.4

 

clear that this gas should be monitored everywhere it is economically possible. However, no simple and cheap method is in use at present to accomplish this task.

 

Many methods for monitoring fruit ripeness based on C₂H₄ concentration have already been proposed, such as gas-chromatography (GC), infrared to visible (IR-Vis) spectroscopy and fluorescence analysis [38*]. The main disadvantage of these methods is that they are not useful for measurement in packinghouses. Moreover, most of these methods require the destruction of the samples during analysis [40]. Therefore, in fruit and vegetable preservation-ripening environments, it would be very important to develop an accurate and reliable system of sensors for on-line C₂H₄ monitoring.

 

C₂H₄ concentration could be precisely measured by GC but this technology is not convenient for monitoring over a long period. It is very costly, requires large volume and is not yet an automated process [28**].

 

Laser-based detection setups involving photo-thermal deflection and photo-acoustics seem to be much more adapted for C₂H₄ tracing [41*].

 

Tin_(IV) oxide (Sn0₂) gas sensor was experimented for monitoring C₂H₄ during fruit ripening [38*]. An error generated by RH on the sensor conductance and response towards C₂H₄ measurements were identified and quantified. An algorithm was developed to compensate for this error. The results show the applicability of this sensor for monitoring C₂H₄ in the agro-industry.

 

Monitoring vibration and impact

Moving produce impacting with a stationary object, a moving object hitting produce, or any pressure or gravity effect on a living produce can generate from light stress to abrasion, or severe bruising or cuts. Although some controlled stresses have been shown to generate a positive response from some produce [42*, 43*], it is generally recognised that uncontrolled stress should be avoided [40]. Thus, living produce must be adequately protected to maintain their good quality.

 

Researchers have been working on several projects related to measuring and simulating road conditions to study their impact on any kind of product (living or inert) and measure the impact of innovative protection systems and materials [44*–53]. More recently, many research projects have been conducted to protect lift and truck drivers against vibration generated by bad road surface conditions or road hazards [54, 55]. However, very little has been published on the development of sensors that are able to sufficiently measure precise vibration or impact and record it over a long period of time.

 

The research in this field must cover the four following steps. First, threshold impact or vibration conditions that produce any detrimental result on the quality of fresh produce must be determined. Second, the possibility of events exceeding these impact or vibration thresholds must be evaluated under various conditions including transportation methods, surface conditions and system devices; packing methods, devices and materials; protection materials and methods; and even consumer behaviour at the store level. From the results of these two first steps, an economical evaluation should be performed to justify the research and development needed to modify the necessary food systems. Finally, adequate transportation and handling methods and materials, and event measuring and recording devices for tracking the sources of eventual problems, should be developed where it is economically feasible. Examples of this four-step method are presented here.

 

Lee et al. [56] evaluated the effect of impact force on Roma tomato quality. Pretreated fruit were individually suspended and impacted by a pendulum with various angles. Fruits impacted with a force equivalent to a 400 and 600 mm drop ripened to full red colour 1–2 days faster and had 25–40% more peak ethylene and 15% more peak production than the controls. Tomatoes impacted with the force equivalent to a 200 mm drop were not significantly different from the control fruits. Impact force caused no significant differences in electrolyte leakage, total titratable acidity, pH, or total soluble solids content.

 

Dropping fruit from a geometrically increasing series of heights onto a flat steel surface using a pendulum, and counting the number of bruises observed with skin intact was also presented as a method [57*] for rapid assessment of bruise damage. A bruise factor was developed to distinguish it from other measurements of bruising. The bruise factor test requires a sample of 20 fruits and can be conducted in 30 min by an inexperienced operator.

 

During the transportation process, mechanical damage such as bruises, abrasions, cuts and punctures can occur causing a decrease in fruit grade. Tests [58*] were conducted to identify the magnitude of damage incurred by apples in bulk bins during semi-trailer transportation on a rough interstate highway. Various bulk bin designs, trailer suspension systems, and trip distances were evaluated. Damage-free apples were used in tests and accumulated damage was measured. Tested fruit positioned in the middle of each bin had similar bruise and abrasion damage levels regardless of the bin design, suspension system or trip distance. Abrasion damage on the side wall of test apples varied among bin design, suspension system and trip distance. Abrasion damage on these fruits was significantly less with the air-cushion system. Plastic bins had much less abrasion damage on the sidewall test fruit than did the hardwood and plywood bins. In this particular experience, the range of abrasion damage on the sidewall test apples was 0.6–65%.

 

Results from a 3-year cross-country transit study [59*] showed that transit vibration injury can be significantly reduced by packing Bartlett pears in polyethylene film bags. Pears packed in slitted polyethylene film bags cooled faster than in conventional tight-film packages. Slitted bags were also effective in reducing vibration injury.

 

Following these types of results [59*, 58*], some researchers tended to identify vibration or impact during transportation as  the sources of many bruising problems. Bruising often occurs to packaged table stock potatoes while they are handled and transported from commercial warehouses to retail stores. The results of a study [60*] demonstrated that the Black Spot disorder was not developed during transport but Shatter Bruise was frequent and occurred predominantly due to manhandling during loading and unloading, rather than in-transit shock and vibration.

 

Moras et al. [2**] reported excellent work on consumer tendency and habits in store. They presented important results about the number of manipulations a horticultural produce is submitted to before being purchased by consumers. From these numbers it can be clearly concluded that consumer behavior is one of the important sources of potential contamination and physical stress.

 

Various studies show that vibrations produced during transport of fruits and vegetables contribute to their deterioration and could be more important in terms of quality loss than impact normally encountered during the same period. Trials were performed [61*, 62*] using table grapes, tomatoes, cherries, nectarines, pears and strawberries under various conditions of transportation over long periods. The piezoelectric accelerometers and the power spectral density (PSD) reporting method used during these trials were able to record and report the most important vibration frequency encountered over long distant transportation varying from 900–4,400 km.

 

A method for managing quality [63*] is given based on a trade-off between the cost of preventing damage and the cost associated with the reduction in quality. The authors give examples of assessing the relative amount of damage to be expected for handling newly-harvested and stored apples, and the relative energy inputs from manual and machine handling. The implications of strategies for improvement through the whole distribution network are emphasised.

 

Based on sensor technology development and testing of new handling material, reducing impact and vibration damage is possible. For example, using hardwood and recycled fibber should modify container design specifications compared with the ones for corrugated fibreboard containers since material performances are very different. A new way to accelerate the use of new material by reducing the strength requirements of containers shipped in unitised loads is presented [64**]. The rate of container deformation with top loading and the compliance of internal packing material or cushions are newly identified variables governing the compression of bottom containers. Tests performed show that over-the-road shipping vibrations encompass the natural frequencies of most unitised loads and dynamically load the bottom containers. A worst case assessment calculates the maximum load on the bottom tier, expected during truck transportation. The cushion-to-container spring ratio and the rate of increasing container spring rates with top-loading are presented as the primary variables determining dynamic loads.

Conclusions

The technologies and sensors used during the realisation of all these research projects show the potential of monitoring environmental conditions surrounding horticultural produce. Although these technologies seem ready to be used in a traceability system, much more work is still required to adapt sensors and recording devices to allow tracing and tracking of undesirable events through the food chain and develop adequate solutions.

 

 

References

Papers of interest have been highlighted as:

** Essential reading

* Marginal importance

1 

2 Tanner DJ and Amos ND. Modelling product quality changes as a result of temperature variability in shipping systems. In: Proceedings of the 21st International Congress of Refrigeration, Washington, DC 2003: Paper no. ICR0243.

3 Moras P, Llopis S and Ferrand CEL. Thermique, hygrométrie, mécanique: Les trois contraintes physiques de la distribution. Centre technique interprofessionnel des fruits et légumes. Paris, France. Infos Ctifl 2003: 192: 25–28.

4 **As fresh fruit and vegetables move through the distribution chain, spoilage increases and this leads to an important loss of value. Environmental conditions cause losses if an adequate distribution channel for that produce is not followed. Knowledge of the causes of losses and the cost associated with these losses can help identify modifications to environmental conditions needed to obtain optimal handling conditions. This article contains interesting information about consumer tendencies and habits in retail stores. The number of manipulations a horticultural produce is subjected to before being bought leads the authors to conclude that consumer behaviour is one of the important sources of potential contamination.

5 Moras P, Llopis S and Bonneviale L. Fresh fruits and vegetables behaviour towards the climatic and mechanical constraints in the distribution chain. In: Proceedings of the 21st International Congress of Refrigeration, Washington, DC 2003: Paper no. ICR0317.

6 Bøgh-Sørensen L and Löndahl G. Temperature indicators and time-temperature integrators. 3rd Informatory Note on Refrigeration and Food, International Institute of Refrigeration. Bull. IIF-IIR 2005: 85 (2005-2):4–11.

7 **This is a “must read” reference that describes in detail the use of TI and TTI. It includes a good description of their functions, design requirements, potential advantages and problems associated with their use, and a description of the operating mechanisms for three types of device that are presently commercially available.

8 Nicolaï BM, Bobelyn E, Hertog M, Marquenie D, Verboven P and Verlinden B. Quality manipulation and monitoring in processes: product-climate interaction, quality control. Proc. Int. Conf. Quality in Chains. Acta Horticulturae 2003: 604:265–275.

9 *This article presents some recent and exciting developments related to quality monitoring and tracing, and advanced control methods to extend the storage life and increase the quality of fresh fruits and vegetables.

10 *Opara LU. Traceability in agriculture and food supply chain: a review of basic concepts, technological implications, and future prospects. Journal of Food, Agriculture and Environment 2003: 1(1): 101–106.

11 Vigneault C and Émond JP. Reusable container for the preservation of fresh fruits and vegetables. Agriculture and Agro-Food Canada and Laval University. 1998: United States Patent no 5,727,711. 60pp.

12 **This patent presents the concept of reusable plastic containers and the characteristics of an efficient container for maintaining the quality of fresh fruit and vegetable during handling from field to consumers.

13 Woolfe ML. Temperature monitoring and measurement. In: Chilled Foods. 2nd Edition. Edited by Stringer M and Dennis C (editors). Abington, Cambridge, GB: Woodhead Publishing 2000: 99–134.

14 **This is an excellent review of temperature monitoring procedures to be used in the cold chain and types of temperature measurement devices available. The author describes which temperature to monitor (air temperature or produce temperature) in different segments of the cold chain, where to measure temperatures in each segment and what types of equipment are available to monitor temperatures.

15 Goyette B, Vigneault C, Panneton B and Raghavan GSV. Method to evaluate the average temperature at the surface of horticultural crop. Canadian Agricultural Engineering 1996: 38(4):291–295.

16 Anonymous. Télégestion – Bien gérer son installation frigorifique. Supplément Énergie Plus 2001: 260:3–6.

17 Anonymous. Télégestion et surveillance de la chaîne du froid. Supplément Énergie Plus 2001: 260:7–9.

18 Tanner DJ and Amos ND. Temperature variability during shipment of fresh produce. Proc. Postharvest Unltd. Acta Horticulturae 2003: 599:193–203.

19 *This paper presents measured data from typical container and refrigerated vessel shipments, monitored throughout voyages from Australasia to markets in Europe. Thermographic plots of the temperature distribution in stows are presented. A number of factors considered likely to have caused the variability are also proposed.

20 Giannakourou MC, Koutsoumanis K, Nychas GJE and Taoukis PS. Development and assessment of an intelligent shelf life decision system for quality optimization of the food chill chain. Journal of Food Protection 2001: 64(7):1051–1057.

21 Morris SC, Jobling JJ, Tanner DJ and Forbes-Smith MR. Prediction of storage or shelf life for cool stored fresh produce transported by reefers. Proc. Int. Conf. Quality in Chains. Acta Horticulturae 2003: 604:305–311.

22 Vass N. Tracking the weakest links in the cold chain. Frozen and Chilled Foods Europe. 2002: 56(7):23–25.

23 Smolander M, Alakomi HL, Ritvanen R, Vainionpää J and Ahvenainen R. Monitoring of the quality of modified atmosphere packaged broiler chicken cuts stored in different temperature conditions. A. Time-temperature indicators as quality-indicating tools. Food Control 2004: 5:217–229.

24 *This paper contains a very good description of the types of reactions that occur in three different types of commercially available time-temperature integrators.

25 Labuza T, Belina D and Diez F. Food safety management in the cold chain through “expiration dating”. http://www.iaph.uni-bonn.de/coldchain/downloads/Labuza_ paper.pdf

26 **The authors explain how an expiration date on a food item can be set based on a food safety parameter, eg, growth of a pathogen. The authors explain how both chemical and electronic RFID TTI can integrate this abuse and relate it to shelf-life expiration.

27 Mendoza TF, Welt BA, Otwell S, Teixeira AA, Kristonsson H and Balaban MO. Kinetic parameter estimation of time-temperature integrators intended for use with packaged fresh seafood. Journal of Food Science 2004: 69(3):90–96.

28 Anonymous. CRYOLOG TRACEO^®, the transparent ‘smart’ label to trace food quality from the factory to the fridge. Food Protection Trends 2006: 26(4):253–254.

29 Kogure H, Kawasaki S, Nakajima K, Sakai N, Futase K, Inatsu Y, Bari ML, Isshiki K and Kawamoto S. Development of a novel microbial sensor with Baker’s yeast cells for monitoring temperature control during cold food chain. Journal of Food Protection 2005: 68(1):182–186.

30 Welt BA, Sage DS and Berger KL. Performance specification of time-temperature integrators designed to protect against botulism in refrigerated fresh foods. Journal of Food Science 2003: 68(1):2–9.

31 Giannakourou MC and Taoukis PS. Systematic application of time temperature integrators as tools for control of frozen vegetable quality. Journal of Food Science 2002: 67(6):2221–2227.

32 Giannakourou MC and Taoukis PS. Application of a TTI-based distribution management system for quality optimization of frozen vegetables at the consumer end. Journal of Food Science 2003: 68(1):201–209.

33 *Singh RP. An evaluation of time temperature indicator labels used to track cut lettuce quality in the cold chain. http://www.vitsab.com/PDF/V509.pdf

34 Anonymous. Ooshop.com, le cybermarché de Carrefour, adopte la puce Fresh-Check. Revue Générale du Froid & du Conditionnement d’Air 2006: 1060:17.

35 Anonymous. Agroalimentaire et distribution croient aux étiquettes intelligentes. Revue Générale du Froid & du Conditionnement d’Air 2006: 1060:12–13.

36 Moras P and Bonneviale L. Les espaces de vente dans les GMS: Une affaire de climat! Infos – Ctifl 2001: 177:31–35.

37 **Kader AA (ed). Postharvest technology of horticultural crops. 3^rd edition. Cooperative Extension of University of California, Division of Agriculture and Natural Resources, University of California, Davis, CA. Publ. no. 3311. 2002.

38 Goyette B, Vigneault C and Raghavan GSV. Effect of argon on gas chromatographic analysis for controlled atmosphere storage. Transaction of the ASAE 1994: 37(4): 1221–1224.

39 Linke M and Geyer M. Determination of flow conditions close to the produce. In: Artés F, Gil MI and Conesa MA (eds). Refrigeration Science and Technology Proceeding: Improving postharvest technologies of fruits, vegetables and ornamentals. International Institute of Refrigeration. Murcia, Spain 2000:19–21 October, 1: 180–186.

40 *This research tries to maintain the quality of perishable horticultural produce by analysing and improving the environmental conditions close to the produce in postharvest. A non-destructive method to determine the flow conditions against and around the produce is presented.

41 Lukasse LJS, Sanders MG and de Kramer JE. Automatic produce quality monitoring in reefer containers. International Conference on Quality in Chains. An Integrated View on Fruit and Vegetable Quality. Acta Horticulturae 2003: 604:313–322.

42 Howell RH, Pascua R, Wooles L and Goebel S. Spatial and temporal variation of relative humidity and temperature in supermarkets. 20^th International Congress of Refrigeration, International Institute of Refrigeration, Sydney, Australia 1999: (5): Paper 110: 7pp.

43 *It is necessary to know the typical store RH in order to evaluate the energy savings produced by reducing store RH. Eight supermarkets in the Tampa, Florida area were monitored for twelve seven-day periods between November 1997 and October 1998. Various categories of supermarkets were included and five different areas within each store were monitored. Result of the study and data analyses are presented.

44 Brecht JK, Chau KV, Fonseca SC, Oliveira FAR, Silva FM, Nunes MCN and Bender RJ. Maintaining optimal atmosphere conditions for fruits and vegetables throughout the postharvest handling chain. Postharvest Biology and Technology 2003: 27: 87–101.

45 *CA and MA optimal conditions for fresh produce vary with the specie, the maturity, and the duration of the storage. Thus, individual batches of produce are generally maintained at various temperatures during the transportation, storage and retail display. The potential for using different atmospheric conditions for mangoes and strawberries is presented based on the storage length, temperature and transporting conditions.

46 Smyth AB, Talasila PC and Cameron AC. An ethanol biosensor can detect low-oxygen injury in modified atmosphere packages of fresh-cut produce. Postharvest Biology and Technology 1999: 15: 127–134.

47 **A commercial biosensor is presented as a simple technique to detect low-O₂ injury.

48 Markarian NR, Vigneault C, Gariépy Y and Rennie T. Design of an advanced control software for controlled atmosphere storage. Computers and Electronics in Agriculture 2003: 39 (2003):23–37.

49 Shiina T, Sase S and Ijiri T. Modeling gas transport through non-hermetic packaging materials. ASAE St-Joseph, Mi 1993: Paper No 93–6510. 10pp.

50 Rudolphij JW and Wang H. The realisation of prescribed climatic conditions in refrigerated containers for flower bulbs. 19^th International Congress of Refrigeration, International Institute of Refrigeration, The Hague, Netherlands 1995: (2): Paper 110: 596–603.

51 *This project aimed to advise on new directions for ventilation requirements for flower bulb transportation or to advise on the use of other systems for the removal of produced ethylene.

52 Giberti A, Carotta MC, Guidi V, Malagù C, Martinelli G, Piga M and Mendemiati B. Monitoring the ethylene for agro-alimentary applications and compensation of humidity effects. Sensor and Actuators B: Chemical 2004. (103): 272–276.

53 *This paper presents the utilisation of a Sn0₂ gas sensor for monitoring ethylene during fruit ripening period.

54 Hoyer L. Investigations of the ethylene build-up during transport of pot plants in controlled temperature trucks. Postharvest Biology and Technology 1995: (5): 101–108.

55 **Ethylene levels were monitored during pot plant transport in two trucks during 70 delivery trips. Samples were collected frequently. Important results are presented.

56 Barrett D, Somogyi L and Ramaswamy H (eds). Processing Fruits, Science and Technology. 2nd edition. CRC Press 2004: 841pp.

57 de Vries HSM, Harren FJM and Reuss J. In situ, real-time monitoring of wound-induced ethylene in cherry tomatoes by two infrared laser-driven systems. Postharvest Biology and Technology 1995: 6: 275–285.

58 *Laser-based detection setups involving photo-thermal deflection and photo-acoustics are shown to be useful to monitor ethylene release during ripening cherry tomatoes mechanically wounded.

59 Charles MT, Kalantari S, Corcuff R and Arul J. Postharvest quality and sensory evaluation of UV-treated tomato fruit. Acta Horticulturae 2005: 682:537–540.

60 *Utilisation of stress as a mean to increase food quality and induced resistance to treated horticultural produce is presented. In this particular case, UV was used for inducing the disease resistance on tomato but many other sources of stress could have positive effects.

61 Mercier J, Roussel D, Charles MT and Arul J. Systemic and local responses associated with UV- and pathogen-induced resistance to Botrytis cinerea in stored carrot. Phytopathology 2000: 90 (9): 981–986.

62 *This reference presents the same subject as reference [42] but using carrots instead of tomatoes.

63 Armstrong PA, Timm EJ, Schulte NL and Brown GK. Apple Bruising in Bulk Bins During Road Transport. ASAE, St-Joseph, MI 1991: Paper No. 91–1020: 12pp.

64 *Apple damages occurring during transportation were studied relative to three bulk bin types and two truck suspension types on typical secondary roads. Apple resonated at frequencies from 5 to 14 Hz, with some dependence on the stiffness of the bin bottom.

65 Bartsch JA, McLaughlin NB and Pitt RE. A computerized control and data acquisition system for a universal testing machine. Journal of Texture Studies 1987: 17: 315–330.

66 Bentini M, Guarnieri A and Manfredi E. Theoretical experimental analysis of fruit breaking during harvesting, handling and transport of industry tomatoes. Rivista-di-Ingegneria-Agraria 1992: 23(2): 116–126.

67 Fisher D, Craig WL, Watada AE, Douglas W and Ashby BH. Simulated in-transit vibration damage to packaged fresh market grapes and strawberries. Applied Engineering in Agriculture 1992: 8(3): 363–366.

68 Jones CS, Holt JE and Schoorl D. A model to predict damage to horticultural produce during transport. Journal of Agricultural Engineering Research 1991: 50: 259–272.

69 Rao BKN, Jones B and Ashley C. Laboratory simulation of vibratory road surface inputs. Journal of Sound and Vibration 1975: 4l (l):73–84.

70 Sargent SA, Brecht JK and Zoellner JJ. Instrumented sphere impact analyses of tomato and bell pepper packing lines. Applied Engineering in Agriculture 1992: 8(1): 76–83.

71 Singh A and Singh Y. Low range vibrations measuring & recording instrumentation systems. Agricultural Review 1991: 12(3): 115–120.

72 Singh A and Singh Y. Effect of Vibrations during transportation on the quality of tomatoes. Agricultural Mechanization in Asia, Africa and Latin-America 1992: 23(2): 70–72.

73 Vergano PJ, Testing RF and Newall WC Jr. Peach bruising: Susceptibility to impact, vibration, and compression abuse. Transactions of the ASAE 1991: 34(5): 2110–2116.

74 Cann AP, Salmoni AW and Eger TR. Predictors of whole-body vibration exposure experienced by highway transport truck operators. Ergonomics 2004: 47(13):1432–1453.

75 Tsujimura H, Taoda K and Nishiyama K. Evaluation of forklift trucks operated in dockyards for reducing exposure to whole-body vibration. Sangyo Eiseigaku Zasshi (Japan) 2005: 47(2):55–66.

76 Lee EB, Adrian D and Sargent SA. Impact thresholds to maximize postharvest quality of Roma-type tomato. Proceeding of Florida State Horticulture Society 2004: 1 (17):373–377.

77 Pang DW, Studman CJ, Banks NH and Baas PH. Rapid assessment of the susceptibility of apples to bruising. Journal of Agricultural Engineering Research 1996. 64: 37–48.

78 *Dropping fruit from a geometrically increasing series of heights onto a flat steel surface using a pendulum, and counting the number of bruises observed with skin intact is presented as a new method for rapid assessment of bruise damage. A bruise factor is developed to distinguish it from other measurements of bruising.

79 Timm EJ, Brown GK and Armstrong PR. Apple damage in bulk bins during semi-trailer transport. Applied Engineering in Agriculture 1996: 12(3): 369–377.

80 *During the transportation process, mechanical damage such as bruises abrasions cuts and punctures can occur causing a decrease in fruit grade. Tests were conducted to identify the magnitude of damage incurred by apples in bulk bins during semi-trailer transportation on a rough interstate highway.

81 Slaughter DC, Thompson JF and Hinsch RT. Packaging Bartlett pears in polyethylene film bags to reduce vibration injury in transit. Transactions of the ASAE 1998: 41(1): 107–114.

82 *Results from a three-year cross-country transit study showed that transit vibration injury can be significantly reduced by packing Bartlett pears in polyethylene film bags.

83 Turczyn MT, Grant SW, Ashby BH and Wheaton FW. Potato shatter bruising during laboratory handling and transport simulation. Transactions of the ASAE 1986: 29(4): 1171–1175.

84 *Bruising often occurs to packaged table stock potatoes while they are handled and transported to commercial warehouses. The most common type is shatter bruising, which is a break or crack in the potato skin. This study was conducted to verify previous research result about two types of bruising theoretically incurring during transport, namely shatter bruise and blackspot. No blackspot developed during transport; however, shatter bruise was frequent and occurred predominantly due to manhandling during loading and unloading, rather than in-transit shock and vibration.

85 Hinsch RT, Thompson JF and Slaughter DC. Les vibrations plus préjudiciables que les chocs? Effet des vibrations sur la qualité des fruits et légumes emballés, pendant le transport. Revue générale du froid 1994: December 46–50.

86 *Various studies show that vibrations produced during transport of fruits and vegetables contribute to their deterioration and could be more important in terms of quality loss than impact normally encountered during the same period. The trials were performed using table grapes, tomatoes and strawberries under various conditions of transportation.

87 Hinsch RT, Slaughter DC, Craig WL and Thompson JF. Vibration of fresh fruits and vegetables during refrigerated truck transport. Transactions of the ASAE 1993: 36(4): 1039–1042.

88 *Fresh fruits and vegetables experience losses caused by mechanical injuries produced during transportation from farm to market. In cross-country tests with cherries, nectarines, and pears in semi-trailers equipped with steel-spring suspension systems, highest PSD levels were found at about 3.5 Hz. Other frequencies with high PSD levels were 9, 18, and 25 Hz. Similar results were found in tests with fresh tomatoes.

89 Schoorl D and Holt JE. Fresh fruit and vegetable distribution - management of quality. Scientia Horticulturae 1982: 17: 1–8.

90 *Distribution is an integral part of horticulture and it needs to be effectively managed. For fresh fruits and vegetables the management of distribution must be based on the management of quality. This requires an understanding of the nature of distribution, of its components, the produce, the packaging, the environment and the transit time, and of the interactions between these components.

91 **Urbanik TJ. Vibration loading mechanism of unitized corrugated containers with cushion and non-load-bearing containers. Shock and Vibration Bulletin 1984: 54(3):111–121.