Yield and product quality together determine the productivity of a processing plant, which all depends on the condition of all the separate parts throughout the line. Regular and adequate maintenance is needed to avoid breakdown or loss of quality.
By Fabio G. Nunes , poultry processing consultant, Brazil
The poultry industry has experienced significant growth over the last decades, pressured by the ever increasing demand for chicken meat around the world. To cope with this demand, the industry has been witness to a gradual phasing out of manual labour and a concomitant phasing in of processing automation.
The growth of automation experienced by the industry has varied around the globe and differs from country to country, as well as within countries. The significant factor in the degree in which countries embraced automation is the cost of labour and its availability.
In the poultry industry maintenance work was traditionally seen as being mostly related to the preservation of the assets physical condition and assuring the operating ability of the equipment. However, given the increasing presence and importance of machinery in poultry plants, the maintenance work must be seen, and done, from a new and significant perspective.
A plant’s daily operation no longer lies solely in the hands of the plant’s labour force under the supervision of their foremen, but increasingly it relies on the functioning of the machinery. Hence production standards such as quality, yield and efficiency are directly influenced by, and reliant on, the maintenance team. The maintenance team has become a key ally in the daily effort to maximise processes and product quality, yield and efficiency.
Cleaning crates In terms of product quality, poultry processors have the biosecurity of their flocks foremost in their minds. To prevent cross-contamination among farms, it is important to clean and disinfect the plastic crates at the plant before returning them.
To achieve a satisfactory, trustworthy result plants must be able to rely on the good performance of the crate washer. Appropriate water pressure and temperature, clean recirculation filters and unobstructed washing and disinfecting spray nozzles are key elements for the successful operation of the washer and, hence, it must be periodically inspected and serviced when necessary.
Stainless steel only Regardless of the degree of automation and machinery sophistication in a plant, the most important piece of equipment is the overhead conveyor, without which no plant such as we know them, would be capable of operating. Replacing the railing with stainless steel obviates the need for its maintenance.
While costly, steel rails pay back the initial one-time investment very quickly through saved maintenance costs. No matter how good the traction chain is, sooner or later it will stretch out in response to the inherent material fatigue imposed by the daily heavy-duty mechanical stress derived from the line pulling job. When the chain’s life is over, do not think twice, but replace it immediately to keep all equipment working synchronously and, therefore, accurately and dependably.
Wheels and shackles Modern trolleys can no longer depend on cast metal parts such as the old ones did, due to the cost of manufacture and weight reasons. Therefore, their durability, and consequent need for replacement, is dictated by the expectably shorter life time of plastic wheels. Bear in mind that wore down wheels may easily cause the steel spheres to spit off onto the products, becoming a contamination risk with drastic consequences for consumers.
Worn down wheels also increase the mechanical work done by power units and gear boxes, in turn accelerating their fatigue and making them prone to collapse without previous notice. Therefore, it is highly advisable to inspect the wheels, replacing them promptly at the very first sign of fatigue.
Last but not least, shackles are the key element of any overhead conveyor. To deliver the expected result, they must be dimension-homogeneous and in good condition, given their impact on carcass quality and on the efficacy of the process. Therefore, replace missing or damaged ones readily and test them periodically to allow for smooth, homogeneous feet hanging and positioning allowing for appropriate, uniform presentation of the carcasses to every single operator or machine.
Rubbing and stunning Maintain the breast-rubbing panel in good, defect-free conditions and keep it flat and adjusted to rub the birds’ breast from the hanging station through to the entrance of the stunner’s water tub.
The height of the stunner needs to be constantly adjusted to bird height, either manually or hydraulically. Manual lifting apparatus must offer ease of access and afford comfortable, smooth operation. Therefore check it periodically for proper maintenance and lubrication and consult the operation manual provided by the equipment manufacturer for hydraulic jack maintenance.
Settings and readings The control panel, comprised of voltmeter, ammeter and frequency meter, is the stunner’s navigation dashboard, and therefore responsible for the stunning accuracy and results. Check components functioning and accuracy every day by confronting the settings on the panel against the readings made in the tub while in operation.
Should any major deviation between the settings and readings persist, replace the defective part promptly. Assure accuracy and dependability by calibrating the voltmeter, ammeter and frequency meter periodically.
Keep air flowing Scalding tanks, an almost maintenance-free piece of equipment, also needs to be cared for periodically. Replace the blowers inlets air filters periodically and keep air flowing into the tank freely and abundantly.
Pipeline and internal air pipes must be obstruction-free to optimise the rate of heat transfer between water and carcasses along the process line. The steam supply valve must be maintained according to the operation manual for dependability, and the setting thermometer calibrated for accuracy as per the manufacturer’s calibration plan.
Replacing fingers The service plucking machine should be maintained in line with the manufacturer’s recommendations, but inspect the rubber fingers, truly the machine’s core, daily. Ensuring that intact fingers perform smoothly, precisely and dependably contributes to the carcass presentation while reducing the incidence of carcass defect associated with over-adjusted machines thanks to damaged fingers.
Therefore, replacing missing, torn or wore down fingers every day becomes of paramount importance. Opting for using good quality rubber fingers is in the long term more cost-effective than choosing more economically priced rubber fingers.
Always sharp and clean If a company is dependent on manual labour on its evisceration line setup, then a few important maintenance aspects are of relevance. Given that dependable compressed air and vacuum supplies are of utmost importance for the operation of the vent and neck cutters, as well as the lung extractor, maintenance of both systems must have top priority.
Additionally, spare sets of venter and neck cutter blades should be available, and their use alternated daily. The blades must be kept sharp for clean, quick, and accurate cutting, which maximises yield and efficiency. Cleaning and degreasing the lung discharging pipeline weekly, will improve the extraction’s efficiency while reducing carcass contamination if the pipeline is kept clear.
The gizzard machine works best on a high-pressure water supply. Follow the manufacturer’s recommendation for optimal cleansing. For better, consistent opening and peeling results use a vidia-edged blade; a hard, durable material that dispenses with sharpening. Check pinch-off rolls bushes regularly and replace worn down ones to prevent gizzard loss. Carcasses must be frequently washed to keep them as clean and free from contaminants as possible. For best washing results, maintain proper water pressure and keep nozzles unobstructed and precisely adjusted so that the outer surface of the carcasses are fully covered.
Skilled evisceration maintenance The complex construction of the automatic evisceration machinery demands skilled maintenance work and an inventory of key spare parts to back it up. It is also important to adhere to the manufacturer’s recommendations. Together they’ll secure smooth and uninterrupted operation, and in doing so improve quality, yield and productivity while eliminating downtime and extending the costly equipment’s life.
On a daily basis, though, the demands placed on the maintenance team will be more restricted and simpler, but as important for the achievement of the operational results. Experience shows that in some companies the maintenance team is in charge of adjustment of the evisceration equipment and the on-the-go maintenance, while in some others this duty is assigned to the line operator. In the latter case, the maintenance department must coach the operators, to extract the best results possible from the working hours.
Fine-tune continuously Venting and opening machines should always be equipped with sharp blades for precise vent removal without cutting the abdominal skin, and for a lengthy, clean opening, while preventing damage to the breast, optimising evisceration, washing and cooling.
The eviscerator continuously needs to be fine-tuned to the carcasses being processed either by the machine operator or the maintenance team’s person, for optimal operation thus preventing damage to carcasses and giblets, while reducing either fall-back or fall-off of the package. This will secure a minimum 85% lung extraction along with the viscera package.
To maximise the cropper performance fins need to be adjusted properly. Too close and they are ineffective. Too open and they may fracture the ‘wish bone’, shooting bone chips into the breast meat; twisting and breaking the ribs, which increases cut-up line downgrades percentage, or even scraping off the neck tissue, reducing water pick-up. The final inspection machine depends on the recommended, stable vacuum levels, a low percentage of remaining lungs and an unclogged discharge line for best results. Adjusting the neck breaker to cut necks off level to the wing joints increases yield.
Thorough washing The inside-outside bird washer performs the thorough washing of the carcasses, preventing the contaminants adhering to the inner and outer surface of the carcass entering the chilling line. Carcasses entering the chilling line with a reduced bacterial load reduces cross-contamination, while a small organic matter load requires less chlorine, therefore increasing the availability of free chlorine and its cross-contamination inhibition capabilities. To optimise the performance of this piece of equipment a few, simple, but important actions are required:
1) Maintenance program: Adhere to the recommendations from the equipment manufacturer.
2) Water pipeline filter: The filter avoids the obstruction of the nozzles, therefore this needs to be cleaned regularly.
3) Water flow meter: To secure a consistent, trustworthy reading calibrate the flow meter as per the QA program recommendation.
4) Hydraulic hoses: A durable component of the machinery, they need only be replaced when either damaged or torn down.
5) Water leakages: Inspect the machine’s gaskets and rings to prevent water leakage and conserve water.
6) Nozzles: Irrespective of their position or function, all nozzles need to be periodically cleaned.
7) Lubrication: Periodic lubrication is required using either edible oil or grease. The practice helps to secure a smooth functioning of the machine and extends the life of the moving parts.
Guarantee perfect chilling The water chiller is a relatively simple piece of equipment, requiring simple maintenance. However, for boosting the products’ safety and for contributing significantly to the processing bottom line, it is fundamental to guarantee the smooth, perfect functioning of the entire system. Its most sensitive components are:
a. Augers: These are subject to extreme mechanical effort during the work hours, powered by electric motors and a gear box. Follow supplier recommendations for gear box maintenance and have a spare electric motor available to back up the one in operation, just in case.
b. Clean water flow meters: To cope with country regulations, immersion chillers demand a continuous supply of fresh natural and/or cold water during the work hours. The supply is monitored by water flow meters, which, like any other measuring equipment, must be periodically calibrated.
c. Air blowers: Replace, or clean, air inlets filters periodically to prevent them from clogging. Keep master air pipelines and smaller branch-off pipelines unobstructed, guaranteeing a continuous, clean, powerful air flow into water.
d. Chemical dosing pumps: Dosing pumps must be carefully maintained to secure a homogenous flow of chemicals, where authorised, into water along the shift hours. Follow manufacturer’s recommendations for their maintenance and have a standby pump set up in parallel to the operative one to guarantee the process will never go down.