Hello Sandra.,
Hello Sandra.,
Though you cook your jam past 100 Degree Centigrade ,the important step is filling into bottles to prevent Mold growth. Most yeasts and Molds are heat-sensitive and destroyed by heat treatments at temperatures of 140-160°F (60-71°C) and if the products get filled below this temperature in bottles there is the possibility of Mold growth. Are you adding any preservatives to your jams.
Normally filling should be carried out above 85 degrees centigrade to prevent bacteria and Mold growth .So it is good to monitor your batch the filling temperature every 15 mts or so and the last bottle should have a filling temperature above 85 degrees.
(Check periodically by removing one bottle from line and inserting a digital thermometer in the centre of jar to check the temp and record in your log sheet along with batch/lot no).
Lemon juice can be added but pH of the product should be around 3.5 for proper setting of jam.
Normally Molds enter the system through contaminated bottles or through your envirornment or through your raw materials.
Hence it is essential to keep your plant under hygienic and GMP condition.
Sometimes raw materials can also be the source of Mold contamination. Hence ask for certificate of analysis of microbiological tests for your raw materials (particularly mold count)
And sterilise your filling jars before filling and inspect for dust and filth.
It is also important to use potable water with low count in Processing , and all Machinaries before and after filling should be properly sanitised and swabs taken to control Microbes.
Also take periodic microbial counts (particularly mold count)from the processing areas to maintain plant in good hygienic conditions and humidity levels of processing and filling areas should be between 30-50%.
Air is an impotant factor for mold growth and when bottles are filled above 85 degrees centigrade air in the head space is filled with steam and creates vacuum in side the bottles.
There should be Maintainence of vacuum in filled bottles and check for vacuum in filled bottles at 25-30 degrees centigrade ,if vacuum gets lost bottles will be exposed to air and spoilage will begun shortly.
If you are facing mold growth problem in filled jars,then you can go for sterilisation at 100 degrees centigrade by immersion of filled bottles in boiling water bath immediately after filling of bottles so that the water is few inches above the filled bottles and processing times as per the attached sheet (centre temp of the jam should be 85 degrees) . Tightness of lids is important otherwise seepage of water in bottles will spoil the batch of jam.
Also you have to contact your pectin manufacturer whether the pectin (quality control) will withstand such temperature without deterioration of the product ( jam not setting properly/Partially liquefied) and then decide for sterilisation or you can carry out the trial batch.
Check periodically your jam bottles for microbiological parameters (Tpc,yeast and mold count etc)