Certaintype of materials should not comeinto contactwithfoodor food-related
materials.Thesematerials include,but are not limitedto (in randomorder),
those listed in Table15.1.
15.6.1 Stainless steel
Frequently,stainlesssteelsare the logicalchoice for materials of construction
for production linesin the foodindustry.For supportand cableinfrastructure,
stainlesssteelis preferredto galvanised steelor coated steelbecause the latter
two materials are moresusceptibleto corrosionfor production typeenviron-
ments. It shouldbe bornein mindthat corrosioncan occurwhendissimilar
alloysare in electrochemical contact.The typesof stainlesssteelmostcom-
monly usedare given in Table15.2.
In summary,the advantages of stainlesssteelare:
∑ excellent corrosion resistance;
∑ maintenance-free in mostcases;
∑ strongconstruction is achievedfromlow-gaugematerials;
∑ its attractive finishprovidesa stimulant for cleaning.
Its disadvantagesare:
∑ difficult to work for bothmanufacturer and user;
∑ has hightool wear;
∑ more costlymaterial thansteel.
Table15.1 Non-preferredmaterials
∑ Glass± breakable
∑ Zinc± poison
∑ Lead± poison
∑ Cadmium± poison
∑ Antimony± poison
∑ Plasticswithfree phenol± poison
∑ Plasticswithformaldehyde± poison
∑ Plasticswithplasticisers± poison
∑ Wood± porous
∑ Copper± mayreactwithcleaningfluids,etc.
∑ Brass± mayreactwithcleaningfluids,etc.
∑ Bronze± mayreactwithcleaningfluids,etc.
Table15.2 Typesof stainlesssteel
AISI304 (DINWerkstoffNo. 1.4301) Whenno chloridesare in the environment
or at moderatetemperatures(< 60 ÎC)
AISI316 (DINWerkstoffNo. 1.4401) Whenchloridesare in the environmentand
highertemperatures(> 60 ÎC)
AISI316L(DINWerkstoffNo. 1.4404)
258 Handbookof hygiene controlin the foodindustry