Environmental Engineering Reference
In-Depth Information
compromises of the quality and safety of the food product that could eventually result in
scrapping.
Waste of the process itself is due to obsolete equipment, lack of adequate process control,
poor equipment maintenance, inadequate equipment size, or equipment that causes damage to
the raw material.
Excess inventory happens by similar reasons as overproduction. The main risk of excess
inventory, either of raw materials or products, is reaching their expiration date while they are
still in the warehouse or shortening the shelf life of the products once they reach the retailer.
Consequences are wasted money, energy, and raw materials. When products require refrigera-
tion, the impact of excess inventory becomes even more significant.
When a food product has not been processed correctly, chances of correction of defects by
rework are normally slim. Suspected products are either inspected—to separate the defec-
tives from the nondefectives—or disposed of, resulting in a waste of money, energy, and
resources.
Implementing lean in food manufacturing
Lean focuses on five primary elements: manufacturing flow, organization, process control,
metrics, and logistics (Feld, 2001). Each element has many specific tools to help in the
reduction of nonvalue-added activities or wastes. Overall, the most common tools used by
lean are value stream mapping, 5S, poka-yoke, kaizen event, jidoka, just-in-time, and kanban.
Value stream mapping is a graphical technique that facilitates the understanding of the flow
of materials and information as the product or service reaches the consumer. The main goal of
value stream mapping is to identify and reduce waste during the process of production of a
product or service by looking at all steps involved. Value stream mapping is used in lean to
identify nonvalue-added steps that contribute to waste and to implement lean activities
(Environmental Protection Agency [EPA], 2007).
A value stream map is fundamentally a detailed flowchart with several levels that contain
information about mass flows, manpower, energy, and duration required in each step. Each
step in the map is represented with standardized icons that help with the pictorial interpretation
of the value stream map.
5S workplace organization is one of the first methods that is normally applied in lean
manufacturing. 5S stands for sort, set in order, shine, standardized, and sustain. Often a
sixth “S,” safety, is added, becoming 6S. 5S, or 6S, is designed to improve productivity by
maintaining an organized workplace and implementing a set of visual cues, which contrib-
utes to achieving more consistent results. The idea is that by maintaining a tidy workplace,
workers are more supportive of the initiative to reduce waste (EPA, 2007), and there are less
chances for mistakes.
Poka-yoke is a concept of lean manufacturing intended to prevent mistakes or to make
mistakes obvious once they occur, thus avoiding defective products to reach customers. Poka-
yoke, or mistake-proofing, is implemented by designing processes, equipments, and methods
in a way that cannot be incorrectly operated by either operators or customers.
Kaizen event is a tool for rapid process improvement that uses other lean tools such as
value stream mapping or 5S. A kaizen event, which is a team activity designed to eliminate
waste and introduce rapid changes in a process, is normally executed in three phases: planning
and preparation, implementation, and follow up (EPA, 2007). In the planning and preparation
phase, people involved in a particular process are brought together and ask to map the process.
The points needing improvement are identified and implementation strategies are discussed.
Changes are then implemented and followed up to confirm their effectiveness.
