5 replies to this topic

[Boykie]

Hi All,

 

I'm currently wrestling with a problem I figured would be best put to the group.

I have 2 different types of washers used to wash Fruit, Salads, Herbs & Vegetables into our high care area.

The washers have the capacity to hold 1000 litres of water which is concentrated to an ideal of 120 parts per million of peracetic acid.

The washers run almost all day with the exception of a few hours when they go into a hygiene window.

The different groups of material can be washed on either washer, but one is better for leafy materials and the other for fruit.

Each of the material groups have different maximum batch sizes that can be washed down each of the washers.

The problem I'm wrestling with is the best way to determine the ideal points to drop the water between batches or different produce groups (or even if I should) and how long to actually run if it's a long batch of one type.

Has anyone done any similar work of this nature or do you have any resources you can point me towards?

Thanks in advance ...


 

[Charles.C]

Hi All,

 

I'm currently wrestling with a problem I figured would be best put to the group.

I have 2 different types of washers used to wash Fruit, Salads, Herbs & Vegetables into our high care area.

The washers have the capacity to hold 1000 litres of water which is concentrated to an ideal of 120 parts per million of peracetic acid.

The washers run almost all day with the exception of a few hours when they go into a hygiene window.

The different groups of material can be washed on either washer, but one is better for leafy materials and the other for fruit.

Each of the material groups have different maximum batch sizes that can be washed down each of the washers.

The problem I'm wrestling with is the best way to determine the ideal points to drop the water between batches or different produce groups (or even if I should) and how long to actually run if it's a long batch of one type.

Has anyone done any similar work of this nature or do you have any resources you can point me towards?

Thanks in advance ...


 

 

Hi Boykie,

 

I assume "drop" =  change

[Scampi]

This would be from sampling the wash water repeatedly to determine after how much of product X or hours used is there no longer and PAAleft to adequately reduce the microbial load

 

The PAA will last a lot longer than chlorine, however, the agitation factor will greatly reduce the length of time you get for each washer. Is there make up water being added constantly and if so, is it being dosed to 120 ppm?

 

So, hopefully you've been checking the ppm since inception and you simply need to input that against the #KG of product that was washed and do the math

 

If you have not been checking the ppm faithfully, that's where you should start.......once an hour for at least a week.........then do the math against what was washed

 

Obviously this will vary depending on the microbial load of the produce at any given time, but you should account for worst case scenario when deciding. I know organizations are really concerned about the cost of potable water.

 

In poultry chill tanks, I have sampled the water once per hour for a month for:

e coli

salmonella

level of PAA

Once we were able to prove that with the maximum amount of carcasses in the tank, and zero e coli and salmonella, the wash water was used for more than 1 day

 

 

So this really depends on what you find in the water

Good luck (this is going to take some time to do properly)

[Boykie]

Hi Boykie,

 

I assume "drop" =  change

 

Hi Charles,

You assume correctly ...

 

[Boykie]

This would be from sampling the wash water repeatedly to determine after how much of product X or hours used is there no longer and PAAleft to adequately reduce the microbial load - The system automatically doses PAA to maintain it's range, so it does not get to the point of there being no PAA left. There will always be PAA unless the supply runs out.

 

The PAA will last a lot longer than chlorine, however, the agitation factor will greatly reduce the length of time you get for each washer. Is there make up water being added constantly and if so, is it being dosed to 120 ppm? - Yes, there is make up water being added and it is dosed proportionally. The water is also recirculated i.e when displaced it funnels back into the re-circulating tank and is pumped back out again. 

 

So, hopefully you've been checking the ppm since inception and you simply need to input that against the #KG of product that was washed and do the math

 

If you have not been checking the ppm faithfully, that's where you should start.......once an hour for at least a week.........then do the math against what was washed. Fortunately the system does come with an internal datalogger that's set to log ppm every minute. When you say do the math, I presume you were thinking of a system that doses once and then stops and to do the math of figuring at what point the PAA concentration falls below specification? As mentioned, this system automatically keeps dosing to maintain the ppm level.

 

Obviously this will vary depending on the microbial load of the produce at any given time, but you should account for worst case scenario when deciding. I know organizations are really concerned about the cost of potable water.

 

In poultry chill tanks, I have sampled the water once per hour for a month for:

e coli

salmonella

level of PAA

Once we were able to prove that with the maximum amount of carcasses in the tank, and zero e coli and salmonella, the wash water was used for more than 1 day

 

 

So this really depends on what you find in the water

Good luck (this is going to take some time to do properly)

The other variable we'll also need to consider is 'taint'. Some fruits, vegetables or salads can leave behind a colour, taste or smell that would affect the next incoming material. A good starting heuristic then would be to change the water between different groups.

 

Thanks Scampi.

It looks to me like the next stage will be to sample the water on different groups for different lengths of time.

As I type this I've realised the other variable is simply how much sediment collects ...




 

[012117]

Hi, Boykie.

 

While my experience with rinse water were not especially with fruits, the experience is relatively the same as what Scampi said. The leading indicator is to check that the concentration is retained in the rinse water tank. Since there will be many "addition" or "dilution", if this is not checked against worst case scenario (e.g. heaviest load, load with the biggest surface area or usually material with the "dirtiest"), they it may be "concluded" that the same applies all throughout. If the frequency will be too much, a matrix may be created, again find the balance between operating and safe use.

 

Another is , if the washer is with rinser or nozzle, you may want to check if the collect dirt and debris not really block the opening of the nozzles or lessen the pressure. This may also impact the effectiveness of the washer.

 

On my experience with rinse water, PAA dissipate faster than chlorine, the concern with chlorine is you may also need to check the pH (and temp perhaps) and may require longer "contact" time to determine the residual concentration.