Postharvest Biology and Technology 45 (2007) 307–316 Modelling the acceptance period of truss tomato batches Rob E. Schouten a,∗ , Tanja P.M. Huijben a , L.M.M. Tijskens a,b , Olaf van Kooten a a Horticultural Production Chains, Wageningen University, Marijkeweg 22, 6709 PG Wageningen, The Netherlands b Group AFSG, Wageningen UR, P.O. Box 17, 6700 AA Wageningen, The Netherlands Received 28 August 2006; accepted 17 March 2007 Abstract Tomato batches are characterised by large variation in the quality attributes colour and firmness. Acceptability of tomato batches is consequently affected by the colour maturity and firmness maturity. In this paper, a model for the acceptance period (AP) is presented that describes the acceptability of tomato batches as the time that all quality attributes are considered acceptable as a function of the maturity at harvest. This model takes into account that tomatoes can first be unacceptable due to being over-ripe, then be acceptable, and then be unacceptable again, due to being over-ripe. Furthermore, the AP model takes also into account that consumers may not consume all tomatoes in a truss at the same time, some immediately and some in 3–4 days time. This is accomplished by combining the acceptance period for future and immediate consumption and taking the intersection of those two as the overall AP to indicate whether tomato batches are suited for both types of consumption. The AP model combines the effects of biological variation, varying consumer limits and the variation in the time of consumption into a practical method to assess acceptability of tomato batches at harvest. The AP model was based on three experiments. In the first and second experiment several tomato batches, differing in harvest maturity, were harvested and stored at three different temperatures. Colour and firmness was measured non-destructively and repeatedly over time so as to estimate the colour and firmness maturity at harvest for each batch. The third experiment was used to determine the consumer limits for today’s consumption and consumption over the weekend. By combining the results from all experiments it was possible to estimate the AP as a function of the maturity at harvest, storage temperature and storage duration. The AP model might be used as a tool for growers to assess the acceptability of tomato batches periodically to analyse and solve quality issues or by optimising the compliance to consumer acceptance by varying the storage temperature and transport time to the retailers. Both applications may help to increase profitability in terms of repeated purchase by consumers. © 2007 Elsevier B.V. All rights reserved. Keywords: Consumer limits; Colour; Firmness; Non-destructive; Modelling 1. Introduction Increasingly, tomato producers in The Netherlands do not sell their products at auctions, but are producing to fulfil contracts between growers and wholesale traders/markets. Such contracts are planned months to a year before the actual tomato harvest. After harvest, each step of the chain is predefined. Harvested tomatoes are transferred in a relatively short time and in con- trolled temperature conditions. In principle, this should enable the production of tomatoes with a predefined, tailor-made qual- ity to optimise the consumer’s acceptability and increase their eagerness for repeated purchase (Schepers and Van Kooten, 2006). A first step towards production of tomatoes with a pre- ∗ Corresponding author. Tel.: +31 317 483527; fax: +31 317 484709. E-mail address: Rob.Schouten@wur.nl (R.E. Schouten). defined quality is the assessment of the tomato acceptability. However, insufficient quantification of the quality at harvest, unknown consumer limits and the absence of a method to integrate quality at harvest and consumer limits prohibits the assessment of tomato acceptability. Two quality attributes of fresh tomatoes are important for consumers: colour and firmness (Tijskens and Evelo, 1994). Tomatoes are generally harvested just after they reach the breaker stage and transported at the lowest temperature that will not induce chilling injury. Depending on the quality at har- vest, the consumer limits, the storage conditions and duration in the horticultural production chain the tomatoes may be unac- ceptable for consumers due to being either unripe (insufficient colour and/or too firm) or over-ripe (too soft). One concept that takes the initial quality, consumer limits, storage temperature and duration into account is keeping quality, the time a com- modity remains acceptable. Another, related, concept is shelf 0925-5214/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.postharvbio.2007.03.012